A look at how to accurately quantify your cardiovascular fitness in order to optimize endurance sports or your cardiovascular health. Is VO2Max the gold standard? Are the metrics in the current “fitness trackers” useful for this goal?

In this episode we look at different ways to track fitness. Previously we have talked about VO2 max and Heart Rate Variability (HRV), along with the trackers (ex. Fitbits) which are used to quantify such physical activity markers.

This episode highlights difficulties and advances in translating physical activity data into meaningful information. We seek to understand what tracking fitness actually tells you about how fit you are? How is your fitness evolving due to training and other changes you are possibly making to your lifestyle? Ultimately, can we usefully quantify cardiovascular fitness yet?

Aiming to accurately capture this, our guest has developed his own approach to analyzing fitness and this is the main topic of this episode.

There is an opportunity.. to quantify what the fitness levels [are] that you can have. You can have feedback… from a health point of view, to see if exercise is having any impact.
– Marco Altini

Our guest is Marco Altini, a PhD Data scientist and entrepreneur working in the middle of the quantified self area. He has spent a lot of time working on heart rate, HRV, fitness, and physical activity analysis via wearable sensors.

Marco has published over 25 papers on the topic. He has a popular HRV4Training app, which is available on the iTunes store. I have used this app myself for over-training monitoring. So he has really done a lot of work in just this specific space.

If you’re in the quantified self community you probably know Marco already because a lot of his posts are widely circulated as these are normally rigorous and interesting. Today he heads up Data Science Activities at Bloom Technologies, where he is using technology and data to help women have healthier pregnancies. We also touch on that.

The episode highlights, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

What You’ll Learn

  • Marco’s research interests and the science behind personalized fitness (3:49).
  • Interpreting accelerometer, heart rate, or calorie meter device data (8:31).
  • Modeling physical activities and normalizing body data to accurately determine energy expenditure (9:54).
  • Using the VO2 max test as a marker for quantifying cardiorespiratory fitness (15:49).
  • The VO2 max test in tracking for performance or health benefits of exercise (19:24).
  • Interpreting VO2 max test results and the drawbacks of normalizing (25:13).
  • Using technology for normalizing results and improving accuracy of quantified fitness (25:54).
  • How to track individual fitness changes (30:23).
  • How Marco’s StayFit app works and distinguishing features from other similar apps (30:38).
  • Key points of analyzing energy expenditure as a fitness marker (33:44).
  • Because fitness improves over long periods, accurate tracking should aim at long – term benchmarks (37:14).
  • The complexity of the relationship between HRV and quantifying fitness levels (38:45).
  • How Marco tweaked his app to adapt measuring heart rate in overall fitness equations (42:28).
  • Normalizing fitness metrics and allowing for un-biased comparison between people (43:26).
  • The importance of context when considering what normalized fitness metrics actually mean for an individual’s results (44:12).
  • Comparing the advantages and limitations of tracking HRV vs. heart rate as fitness biomarkers (46:37).
  • Tracking HRV and fitness parameters in order to prevent pregnancy complications – a Bloom Technologies project (48:22) .
  • Discussing near-future market products and collaborations with major clinical research centers (51:54).
  • How to obtain more information on the topics of this episode (52:50).
  • How best to connect with our guest (53:36).
  • Marco’s recommendations for learning about cardio fitness (53:52).
  • Marco’s approach to tracking his body data on routine basis (54:34).
  • Caveats and useful insight into tracking HRV as a cardiovascular fitness parameter (55:45).
  • Marco’s number one recommendation for improving health, performance, and longevity (57:41).

Thank Marco Altini on Twitter for this interview.
Click Here to let him know you enjoyed the show!

Marco Altini (PhD), Bloom Technologies

Fitness Apps developed by Marco

  • HRV4Training: This app is useful for preventing over-training by measuring HRV and providing personalized feedback on your physical condition. Learn more on their website.
  • StayFit: This app from Marco is based on a novel method for quantifying cardio fitness, known as the Fitness Index developed by Marco Altini. Some of the research backing this up was just recently (after this interview took place) published in the Artificial Intelligence Journal here.
    Note: StayFit is not available on the Apple Store any longer. Marco has integrated the Fitness Index into his main app HRV4Training.

Tools & Tactics


  • Lypo-Spheric Vitamin CLiposome Encapsulated Vitamin C for Maximum Bioavailability; 0.2 fl oz. – 30 Packets | 1,000 mg Vitamin C Per Packet. Damien suggests taking this supplement in response to particularly low HRV test scores. As such, it can be used to prevent potential colds in a timely manner.



  • Maximal Oxygen Consumption (VO2 max): This marker reflects the ability of your circulatory-respiratory system to provide oxygen to your muscles for sustaining exercise. Research has confirmed that low cardiovascular fitness is associated with higher disease risk, including heart disease. A running VO2 max test is more indicative of cardiovascular fitness compared to a biking test which does not require you to carry your entire weight forward. We have previously discussed this marker in the context of wearable devices which estimate VO2 max with Troy Angrignon in Episode 24.
  • Heart Rate Variability (HRV): HRV is the measure of the change in the heart’s rhythm, measured as variations in para/sympathetic stimulation to the heart muscles. HRV is not an ideal marker for tracking fitness improvements because of day to day variability in results. Previously we covered HRV in the context of optimizing training in Episode 1 with Andrew Flatt, longevity in Episode 20 with Dr. Joon Yun. and using HRV to reduce stress in Episode 35 with Richard Gevirtz.
  • Heart Rate: The speed of the heartbeat – measured in beats per minute (bpm). Lower heart rate is associated with stronger cardiovascular ability. Marco recommends tracking resting or active heart rate for tracking overall cardiovascular fitness. Heart rate increases by 10-20 bpm during pregnancy – an important factor to consider when quantifying fitness or risk for pregnancy complications.

Lab Tests, Devices and Apps

  • Basis Peak: A watch functioning as a fitness and sleep tracker.
  • Moves: An exercise tracking app which can detect the type of exercise being performed.
  • FitBit: This company offers wearable devices which include cardiovascular fitness tracking. The FitBit Surge is a fitness watch that offers GPS tracking, heart rate monitor, all-day tracking, and sleep tracking. The FitBit Charge monitors physical activity and sleep quality.
  • Runkeeper: An app which tracks running, walking, cycling, workout, pace and weight and which also lets you manually enter the activity you are performing.
  • MyHeart Counts: A personalized tool that can help you measure daily activity, fitness, and cardiovascular risk developed at Stanford University.
  • Steps: A pedometer and activity tracker app with measures how far you walk and how many steps you take.

Other People, Books & Resources


Full Interview Transcript

Click Here to Read Transcript
[03:49][Damien Blenkinsopp]: Now Marco, thanks so much for joining us on the show today.

[Marco Altini]: Thank you, my pleasure.

[Damien Blenkinsopp]: So I wanted to get first into a story about where you are at, and how you got into measuring fitness and looking at that specifically. What’s your background, and what’s your interest in this area?

[Marco Altini]: So basically I’ve been doing a PhD all around using wearable sensors to monitor energy expenditure. Well, let’s more say on their machine [04:12 check ‘machine landing’] aspects, so integrating multiple data streams [04:16 unclear] to accurate measurements of physical activity. Which is normally what we focus on is energy expenditure. So basically the intensity of the activity.

And taking a step back, let’s say most of the research in the field focused on the component of energy expenditure, which is due to physical activity, right? So body movement, because energy expenditure is actually composed of three elements. So we have diet induced thermogenesis, which is the energy expenditure we expend due to digestion, for example. And that’s something we consider as a sort of standard component, about 10 percent.

Then we have our basal metabolic rate, which is basically the calories we burn at rest. So if we take a bit of a simplistic view, this is what we would consume if we were not doing any activity. We lie in bed all day, and we still consume actually most of our energy which is due to this component. And then the third component is physical activity energy expenditure, which is the calories we burn when we move or exercise.

So by working a lot around this component and trying to estimate this more accurately using accelerometer and heart rate data, then I started focusing on aspects like personalization. Because when you use physiological data like heart rate to estimate energy expenditure you basically rely on parameters which are very well correlated with energy expenditure at the individual level. So for a single person, because of course heart rate is directly connected to oxygen uptake, which is also what we measure when we want to get the reference for energy expenditure.

At the same time there are individual differences between people so you need to try to understand how to model this difference between people in a way that your energy expenditure estimate coming from heart rate is accurate. And while working around this, basically you’ll get the work on what is the problem of basically normalizing heart rate between individuals, which is directly connected to fitness.

Because everyone tends to know that lower heart rate means better fitness. This is true at rest but even during exercise, which is, as a matter of fact, the principle behind, for example, sub-maximal fitness tests.

So, people are brought to the gym and they do an exercise to a certain intensity, and then based on what their heart rate you get, basically a surrogate of their fitness level. And all of that came back as something that you need to account for also when you measure energy expenditure because the whole reason behind normalization is that our metabolic response to exercise is not affected by fitness.

So just as an example to clear this up, if we think about, let’s say two individuals which are the same in terms of age, body weight, body mass, pretty much the same anthropometric characteristics. Then when they do a certain activity, they consume the same energy. So it’s the same kilocalories per minute because that’s mainly driven by the type of activity and the body mass.

However, these two individuals could be having a very different fitness level. So let’s say that one is very fit and while doing this activity their heart rate is very low, and the other one is very unfit and the heart rate is much higher. Then if you use heart rate to estimate the energy expenditure, you would be over or under estimating for one of these people.

[Damien Blenkinsopp]: So the one with the fast heart rate is over estimating?

[Marco Altini]: Yes. If you have a higher heart rate and then you don’t take into account that there is a difference in fitness, then you will assume this person is consuming more energy because the heart rate is higher with respect to the average, let’s say.

But that’s not the case because actually metabolism is not affected by fitness and there have been quite a few studies looking both at rest and during exercise, and given basal metabolic rate the component of energy expenditure.

[08:31] [Damien Blenkinsopp]: So what we’re saying is there are a lot of devices out there right now which are attempting to assess how many calories you’re burning in addition to the steps. So when you’re looking at that, actually, it’s a bit more complicated than the standards currently use, right?

[Marco Altini]: Yeah, exactly. Especially manufactures which are using, providing sensors with heart rate. They like to claim that just because there is heart rate they will be more accurate. And let’s say that using heart rate certainly is already a step forward compared to accelerometers because you can, with minimal effort already take into account energy expenditure for many activities which don’t involve body movement. Right?

For example with accelerometers we have limitations even just biking, because you might have the accelerometer in a place where it doesn’t move when you do these activities. So by using heart rate you can solve, partially, these issues. Because of course your heart rate will increase.

It doesn’t matter if you don’t move if you are doing exercise which is intense and of course requires your heart to pump more oxygen to your muscles. At the same time, due to the fact that the relation with heart rate is very personal, then you need to be able to make an extra step and model that if you want your system to be accurate during intense physical exercise.

[09:54][Damien Blenkinsopp]: Great. So in terms of the tech out there currently, would it be safe to say that a lot of it’s either overestimating or underestimating based on these restrictions or are there devices or apps out there which have tackled this problem?

[Marco Altini]: So I think what we are starting to see a bit more is, for example in the context of even just monitors using, for example movement or steps, some of them are introducing something more around context. Which is important because when you use accelerometers this first instance were probably already in the late 70s, for sure in the early 80s.

The researchers started to develop the first equations to link accelerometer output and movement to energy expenditure. however some of the imitations there are that, for example, the relation between the accelerometer output and energy expenditure changes depending on the activity. So if you are walking or running there’s a different relation. If you are at rest, of course, there is no movement, and all of that.

Recently we started seeing even commercial devices which are able to detect activities. For example, I think the Basis watch is detecting a couple of activities. Even apps like the Moves app can detect activities.

So in general I would assume even though they don’t disclose the methods they use to estimate energy expenditure, I would assume the ones that are able to detect the activity, then what they do they use this table, it’s called the compendium of physical activities. Basically it’s a table where you have almost all possible activities you can think of, and for each of them there is a value of energy expenditure normalized by body weight that people are supposed to be expending while doing that activity.

So these devices are probably mapping the activity they recognize to this level of energy expenditure. This method [11:53 unclear] like four or five years ago, to be much better than using accelerometers without context. But it’s even better than combining heart rate and accelerometers, if you don’t take extra measures like modeling context or normalizing heart rate.

So just putting together accelerometers and heart rate is not able to outperform methods where you use only accelerometer data. But with a bit more of machine learning to be able to recognize what activity is being performed, and then map that to an energy expenditure level.

[Damien Blenkinsopp]: Right. It sounds like if you have the heart rate, and you have the anthropometric data ñ what’s your weight and age and so on — and if you have the accelerometer data showing the movement, and you have an algorithm which categorizes what kind of activity it is based on the accelerometer, what’s that showing.

Which, I know isn’t always correct, based on my experience. So sometimes, for instance, I was wearing the Basis and it would say I’m on a bike where I never got on a bike. So it isn’t quite perfect yet, but we’ll assume that’s getting better. And maybe it’s already better.

Then what they’re doing is they’re looking at the activity and they’re saying, ìWell for this type of activity this heart rate is standard for this kind of fitness, and this heart rate is standard for this kind of fitness.î Is that how it works? Or is it a more basic thing right now?

[Marco Altini]: I think step zero would be simply to map it to known values, regardless of your heart rate. Let’s say, an app without heart rate, like the Moves app. So you just have the activity type, and you map that energy expenditure. Yes, like the average energy expenditure for that activity for a person.

So you are walking, and of course you can walk at many different speeds, so maybe that’s not known by the app. But still you would assume that for the average walking speed for the average person, you would consume this many calories. And when you detect walking you just map it to that and then based on other characteristics you input, like your body weight, you scale that by your body size, basically.

And then if you do a bit of more advanced work, let’s say, and you want to develop your own model for a specific activity. Let’s say you have the Basis, and at Basis they have a couple more physiological parameters together with movement, then it could develop there on regression models by collecting reference data.

So normally we do that with indirect calorie measure. So that’s a device which is a physical mouthpiece, where you breathe and it’s measuring O2 and CO2 counts. So, you compare the O2 and CO2 in body sheets, and that’s basically energy expenditure. So by having people performing different activities wearing the Basis watch, while you measure these reference calorie meter data, then you can see how all these valuables change depending on the activity.

And then you can map, let’s say heart rate changes and movement changes, the energy expenditure for a specific activity. I don’t know if they are doing that, because that would require to do all the tests with a calorie meter. I would assume, considering that they have all that physiological data that they did also this kind of development. While maybe all the other devices which are simply accelerometers, they might have simply used the values from the compendium of physical activity.

Basically the compendium of physical activity is what you use also when you, let’s say you use an app for tracking your workout, like Runkeeper, that let’s you also manually enter the activity. So maybe one day you didn’t have your phone and you want to enter it manually, then it will also estimate your energy expenditure. And that’s basically just a lookup from this table. And then it’s just scaled by your body size and for the amount of time you did the exercise.

[15:49][Damien Blenkinsopp]: Okay great. So what we’re talking about here is physical activity level, right? These are different version of it. There’s energy expenditure, and there’s Steps, which is currently what’s on the market. All these devices are looking at quantifying our physical activity level.

I guess the question is is that what people really want in terms of the end game? Because you’ve got this app out which is trying to get at something which you feel is a bit closer to the end goal of what you want to measure.

[Marco Altini]: Yes, so while I was doing research here on energy expenditure and the more I looked close to the whole personalization story, basically I was thinking what is a way to quantify not only what activity you do, right, the amount of exercise, the Steps, but also what the impact of this activity on your health, if there is any.

So this is a process in which we try to move from quantifying physical behavior to quantifying physical activity related health markers. And one of these markers, which is probably the most important one, is cardiorespiratory fitness.

[Damien Blenkinsopp]: That’s kind of well-known. That’s been the standard for a long time, in terms of quantifying fitness. But it’s only been done in laboratory contexts, as I understand it.

[Marco Altini]: Exactly. So far, as you say, it’s been really, I think 20 or 30 years that we know for sure that all these studies show that low level of cardiorespiratory fitness is indicative of higher risk of getting different sort of diseases. And even in general of just what is called [17:24 check – all cause mortitus], so you’re just most likely to live less if you have a low level of fitness.

And what is interesting here is that it is true even when it’s basically controlled by physical activity or body size. So it means that it doesn’t matter even if you are obese or if you have less levels of activity, but as long as your cardiorespiratory fitness is higher, you tend to be protected with respect of these other issues.

And indeed we know that. The research community at least is well aware of the importance of cardiorespiratory fitness, but in the general population I think we still lack awareness of this. Mainly because, as you say, there are basically no tools. So the way this is measured is in laboratory conditions. The reference is called VO2 max test.

And while VO2 is the oxygen volume and this is called VO2 max basically because the way the test works is that you get people either to do a treadmill test or a biking test in which they bike around until exhaustion. So you increase the intensity of the exercise every 5 minutes or so. And basically there is a point in which an individual is still able to keep it going at that intensity, just a bit before you drop. And then your oxygen sort of plateaus, and that’s your VO2 max.

[Damien Blenkinsopp]: What does that signify? Is that the moment when you switch to anaerobic, or what does it signify physiologically?

[Marco Altini]: Well, there is really the moment in which you cannot take any oxygen anymore. You need to stop. You cannot take any more intense activity, so that’s the max oxygen you can take.

[Damien Blenkinsopp]: Right. So it’s like your maximum ability to metabolize…

[Marco Altini]: It’s the ability of your circulatory-respiratory system to provide oxygen to your muscles for sustaining exercise.

[Damien Blenkinsopp]: Great, great.

[19:24] So showing that efficiency and when people are looking at that list, let’s talk a little bit about the decisions.

Typically when you have these meters when people are using these activity tracking meters for, whether it’s biking and running and so on, typically they want to improve something. They either want to lose weight, sometimes, or they want to improve their fitness. Or they want to improve their health.

So you’ve talked a little just there about cardiorespiratory fitness, we say that that has a protective effect against heart disease, which is one of the biggest killers. And also, if our cardio fitness is better, is more efficient, then we’re probably going to be able to run further, and run faster.

We’re going to be able to perform better, which is also something that we want. Whereas the Steps and the energy expenditure is hard to understand how that reflects either of those two cases, kind of like the use cases: health or better performance.

And with Steps and energy expenditure, you can tell that you’ve done more in terms of quantity but you can’t really tell if it’s going to give you more performance or you’ve actually got health benefits.

[Marco Altini]: Yeah.

So I think there is an opportunity in trying to quantify what is the fitness levels that you can have. You can have feedback for the ones that are interested just from a health point of view, to see if exercise is having any impact. You can have, actually even for professionals it would be, they do the VO2 max test and they know their actual cardiorespiratory fitness level, but still you cannot do that that often and it takes time.

[Damien Blenkinsopp]: It’s expensive, I think it’s like 300 dollars or something. Because I looked up, when I was in the US recently I was going to do one in San Diego and they had a gym that was actually providing it. Sometimes you can go to laboratory health centers or sometimes some advanced gyms will have the equipment to do this.

[Marco Altini]: Yes. I think there are a few limitations around the VO2 max test, apart from the cost.

Certainly you need some medical supervision and you need, again, the calorie meter to measure the oxygen. It requires a level of infrastructure. And apart from that, I think sometimes it’s even tricky to interpret the result. Because VO2 max is normally reported normalized by body weight. So you need to provide people with an easier way to understand their fitness level.

So you have these tables where basically different levels are divided by gender and by age. So if you are a person of a certain age and you’re male, and then you have your VO2 max result and it would soon [21:53 unclear]. Okay?

But however, these tables are not organized by body weight. Only by gender and age, since the results are normalized. However, the exercise type you use to acquire the VO2 max data is not part of those tables. And that has a great influence on oxygen consumption.

Because even just when you normally measure energy expenditure, even if you’re doing an activity which is weight bearing, you literally carry your weight around, like when you walk around, then the link between oxygen consumption and body weight is much stronger compared to when you just bike. Especially for stationary biking in the gym your energy expenditure is much more similar to the one of a person which is of different body size compared to you. While if you would be walking or running there would be a much bigger difference, because it’s a different impact of body weight.

Even, like in one of my recent studies through my PhD I measured VO2 max on a group of 60-70 people, and for example there I had a subject which was unfit; so all the parameters that we measured seemed to show that his fitness level was quite poor. He had very high heart rate at rest, very high heart rate during all exercises, he couldn’t finished some of the protocols. During the free living part also, his physical activity level was very low.

And the VO2 max test [23:25 unclear audio] it turned a result that he was the most unfit person as well. However, if we go to normalize the VO2 max, so we divide by body weight, this guy became the second most fit of the entire data set just because he’s very thin.

And that’s actually the result normalized by body weight, is what you normally get. Because it’s common practice to report it that way. But at that point, how do you interpret it?

[Damien Blenkinsopp]: So it’s a bit tricky to make it. So VO2 max is the gold standard in terms of measuring this.

[Marco Altini]: Exactly, but it has its own limitations. Yeah.

[Damien Blenkinsopp]: If someone was to go and take that test, what would you suggest they make sure, like to check they get a result that’s useful for them. Is there anything they can look out for or ask for?

[Marco Altini]: So in my opinion at this point, I tend to think that maybe a running test would be a better way to do it, because the relation with body weight is a bit more clear than compared to the biking test. However, normally a biking test is done also because of safety reasons. It’s a bit easier to do a maximal test on a bike; it’s a bit more of a controlled situation.

However, when you then go to normalize by body weight, the fact that your body weight doesn’t have the same impact because you’re biking and you’re not carrying your weight around, then you’re [going] to have this weird results like we did where the normalized VO2 max basically makes an unfit person the most fit person. That’s one of the reasons why I prefer to use VO2 max data non-normalized. So I use the value of oxygen consumption they reach, and that’s it. I don’t normalize it by body weight.

[25:13][Damien Blenkinsopp]: Okay. So, are there benchmarks for that? If they get a specific score back they can assume they’re relatively fit?

[Marco Altini]: Yeah, but the problem with that [25:22 unclear] is then you don’t have this [25:23 unclear] they’re not aware of, that there are these tables for matching it to something like, [25:29 unclear], like fitness is poor or average or good. These tables are all normalized by body weight. So that’s sort of a problem.

[Damien Blenkinsopp]: So what you’re saying is if you were to do this twice, you could get your relative fitness without normalization, right? If I took a test today and I took another test in 6 months.

[Marco Altini]: Exactly. You could calculate longitudinally. That’s no problem, maybe it’s more difficult to compare with other people.

[25:54][Damien Blenkinsopp]: Right. So is there any way we can get around the issue of normalization so that it works for us?

[Marco Altini]: There are some maximal tests which are not all bad.

So basically, some maximal tests, the way they work is that of course they want to predict VO2 max, and they rely on the fact that we know, as I was saying before, that the heart rate changes based on fitness.

So instead of doing a maximal test and measuring oxygen consumption until exhaustion, you do tests at a predefined speed. For example you run at a certain speed, you bike at a certain intensity, and then you measure your heart rate. And that goes into an equation that was developed before using referenced to VO2 max, which basically predicts your VO2 max based on your sub-maximal heart rate, and a bunch of other parameters like it measures your age and body weight and all these other parameters.

And the simplest of this test I actually did on [26:57 unclear audio] to measure heart rate, for example. I think something interesting is that we’re seeing now is also to bring awareness to people with [27:09-27:12 unclear audio] and we got this out from Stanford which is called MyHeart Counts, I believe.

So they measure, they ask you a lot of things and get a lot of reference points and your lifestyle and what you do. And then they track, using the phone, your activity. But since the study is all about cardiovascular health, they ask you to do this fitness test, which is one of the most commonly used because of its simplicity, I would say, where you just have to walk for six minutes.

And you have to time it, and you have to check the distance basically. So the longer the distance you go in six minutes, the more fit you are. And again, here you don’t need physiological data, and this might be probably a better test for people which are not in optimal health conditions.

But I think it’s good because the app is also targeting healthy users. So it’s a good indication that fitness should be of interest for the general population. And there is an effort here to raise awareness.

This being said, I think the potential of current technology is much higher. So you can do much better than that. And you can overcome also the limitations you had, because until now you had to either do a VO2 max test, which is expensive and has all the limitations you discussed, or even if you want to do a sub-maximal test you need still to go to a gym, you need to do an exercise at an exact intensity and then do your math to get what your VO2 max would be.

But right now, since we have phones with all sorts of sensors, and then we have wearable sensors and we have heart rate monitors and all of that, and then we have other reasons that can really automatically understand if you’re walking or running or what is your speed. You don’t even need a treadmill anymore to understand the context around the activity you’re doing.

So, some of the work we’ve been doing recently as part of our research is indeed to give people just a phone and a wearable sensor and don’t ask them to do any specific activity. They just live their life for two weeks while wearing the sensor.

And then all the other reasons we automatically understand: which location they are and what kind of activity they’re doing; if they’re walking, then then what is their speed. And then, basically you put your heart rate in a specific heart rate continuously. And by knowing that, since your heart rate still will be affected by your activity and your fitness, and you also rate the activity because you know the context. And then you can estimate the fitness level basically without requiring any test anymore.

So I think that’s quite interesting because you can finally get to something that is useable by everyone and doesn’t require any specific tests. And again, if you want to monitor them longitudinally, you don’t need to do a test every month. Because you just wear the sensor and it’s sort of being continuously updated just by wearing it.

[30:23][Damien Blenkinsopp]: So when you say longitudinally, that means testing ourselves in time, and seeing if we’ve got an improvement or decline over time.

[Marco Altini]: Exactly.

[Damien Blenkinsopp]: See if what we’re doing is actually working or not.

[Marco Altini]: Yeah. To see if there is basically changes at the individual level.

[30:38][Damien Blenkinsopp]: So this is basically what your StayFit app does?

[Marco Altini]: So basically with this app, I tried to make something where you don’t even need the sensor anymore. So [30:48 unclear] yields a research prototypes. Basically it’s a necklace, you wear it and there is, essentially you get full SG. And then we [30:56 unclear] heart rate. Then there is an accelerometer which we use for activity recognition and walking speed. Then with the phone we use GPS to understand location of that.

However, even if now you have some trackers that do heart rate like the latest FitBit or the Basis, we don’t have access as developers to all of their raw data that you would need to develop algorithms on top of these devices. So what I was thinking is, well of course if you have heart rate data during all of these activities, your fitness estimate can be more accurate.

But, at the same time heart rate at rest has been shown to be linked to fitness. So the lower heart rate at rest the higher fitness. This was the case in many studies, even interventions about physical activity trying to increase physical activity, often show that they were also able to reduce heart rate at rest.

So what I did with this app was to combine the two aspects. So using just the phone you can get activity level based on the step count, which is on the phone, and this data is transformed in energy expenditure, and your physical activity level. And then you combine heart rate. And again since you need context, the way the app is used is by taking a short test in the morning, similar to what the HRV apps do.

[Damien Blenkinsopp]: So, just to clarify, that means when you wake up in the morning you take a reading before you do anything else.

[Marco Altini]: Yeah, exactly. So that’s the easiest way to isolate context without having to go through much trouble. You just, you wake up, you take your test, that’s at least the moment we are the least affected by all other parameters and stressors.

And then you get your heart rate at rest, which goes in the system together with a bunch of other parameters to get you an estimate of fitness. And what the app is actually estimating is basically your sub-maximal heart rate, which is then transformed to a number between zero and 100.

But the whole point here is that since sub-maximal tests basically measure your heart rate at a certain intensity, because that’s what then goes into the formula to estimate the VO2 max. But if you consider that your age, and gender, and body weight will stay pretty much the same if you do two tests in a short period of time, then the actual measure of fitness is just sub-maximal heart rate.

So your VO2 max will be different only if your sub-maximal heart rate is different. So, here I removed the VO2 max step and estimate directly their sub-maximal heart rate. Which is a proxy to fitness, basically.

[33:44][Damien Blenkinsopp]: Great. And how have you seen this work out? Because you’ve been using this app for a while, and I guess you’ve gathered some user data now as well?

[Marco Altini]: Yeah, I did. Not that much, I must say. So I cannot really make any analysis yet, especially because I don’t have a reference point either.

It’s more of an individual tool that you might want to use to track your fitness, but I don’t know the VO2 max of the people using it. So maybe it’s something for future versions would be to try to add some other reference points so that I can do some further analysis like I did with HRV apps.

[Damien Blenkinsopp]: Great. So in your own case, how long have you been using the app, and have you noticed any differences in your fitness? For example, your running time, because I know you’re a runner and you developed it primary because of that interest.

So have you noticed or seen differences in your fitness level, in terms of your efficiency and your performance, and seen those correlate within the app, or has it not?

[Marco Altini]: So I used it for about two months. Something interesting I think is around the metrics that I used. So for example, I used the physical activity level as a measure of activity. So the physical activity level is a normalized version of energy expenditure.

So if you’re telling me your energy expenditure today is 4000 kilocalories, I can’t really infer anything, because if you’re severely obese that may be just your energy expenditure at rest when you do an activity, right. At the other end, if you’re a thin person and a small person, then it means that you’re being very active.

So, the total energy expenditure is difficult to interpret without knowing who are we talking about. And the physical activity level is the energy expenditure divided by the basal metabolic rate, so the component result is your metabolism at rest.

In this case you would get a value which is representative of how much you move. So if you don’t move at all it’s one, and if you move a lot it really doesn’t get much beyond two. So that’s a good indication of physical activity.

And it’s based on energy expenditure, which I think is important because sometimes, for example, I could see in my data is that I went for a trip and I did a lot of hiking, which is a lot of activity but at the same time it’s not really cardio activity or activity that I believe would improve my fitness level. It’s not like when you go running you know the intervals on track.

It’s movement but I would assume my fitness stayed more or less constant those days, right? And if I look at Steps, I see that I’ve been much more active than my average, because you walk all day and it’s much more steps than when you go training. So if my fitness was just based on my activity, I would get theoretically more fit when walking on holiday.

However, since we use energy expenditure, the normalized energy expenditure, the physical activity level, that was pretty much the same as it was when I was here and I was training. Because the activity when I train here is much more intense and consumes much more energy than when you’re just walking. So I think that’s a valuable point of using physical activity level as energy expenditure to track fitness instead of just movement or steps.

[37:14][Damien Blenkinsopp]: Okay. So for your hiking and so on, did you see your fitness level change in the app? Because it gives an index of one to 100.

[Marco Altini]: Yeah, exactly. So it stayed pretty much the same.

[Damien Blenkinsopp]: Right. So you saw basically that that case was shown in the results. Did you do anything where you saw your performance improve in your app and you correlated it to basically better times, or other things that seemed to be improving?

[Marco Altini]: For now I just saw it dropping, which is not good. So, yeah. I guess my condition is not ideal.

But I think it is interesting to track over long time. I tracked for two months, and I don’t race that often. Maybe for a professional person it would be more interesting because their life is training. For me it’s more of a hobby.

But I think looking after a year or so, then you can track it. You can look at data with respect to maybe the half marathons you did and the times you did, and then you get all these reference points, then it could be interesting.

So, you know I’ve been doing some work around HRV for example, and there it’s very valuable on a daily basis. Because there were points that you measure basically those points of this test, which can be training, and you get basically daily advice on how to train, and if your body is ready for another intense training. On the other hand this one tracks a parameter which changes much more slowly. Fitness doesn’t change fast.

[38:45][Damien Blenkinsopp]: Right.

So this one strikes me as it would be more useful to understand the effectiveness of your program. Like, the protocols you’re using to increase your fitness, for the longer term? So a lot of people will follow a set program for a while, especially if you’re a professional athlete you’ll have a set workout and timing and everything.

So you can kind of evaluate the performance of that, and if it’s increasing in the fitness one. But as you said, because a lot of people are using the HRV today. We’ve looked at the HRV in the context of stress, of longevity, and also of course the training in terms of recovery, which you just mentioned.

So, I could imagine that some people might look a HRV and be thinking, “Oh, my HRV is higher so I’m fitter.” Right? Because we’re also looking over time rather than the day to day, looking at the trend. Would you say that’s the case? Or do you think that’s not an accurate way to look at HRV?

[Marco Altini]: I think HRV is great as a day to day tool for recording and a proxy to personal activity and it is true that even at the [39:47 unclear – professional] level, let’s say athletes tend to have higher HRV, and really sedentary people tend to have lower HRV.

But, the link between HRV and fitness is, let’s say far from being clear. Meaning that there have been many studies, and some of them found some link between HRV and fitness, meaning higher HRV higher fitness, but many many studies found no relation there. Especially when doing interventions.

So, you know, longitudinal studies where you take people through a training program and then you measure their HRV at the beginning and at the end. And many of these studies found that heart rate changed and it was lower, but they couldn’t find any change in HRV, so it might be that there is a stronger genetic component there.

And also physiologically speaking, with heart rate you train, so you train your heart which then would be basically able to pump more blood. The volume changes, increases per beat, and that’s why your heart rate also decreases. The more fit you get, you train your heart muscle, which is going to be able to pump more blood and oxygen to the muscles, and then your heart rate as a consequence also decreases.

However this link, in terms of HRV, I don’t think it’s clear. So in general, even in this study I was mentioning before where I had all these people doing VO2 max test and doing also all the free living recordings, that was not a longevity study, so we just got a snapshot of these people. But there we can see clearly there is a very strong relation between heart rate and their fitness level.

And this was true for heart rate at rest, heart rate while they were sleeping, heart rate during activities. So you always see this relation which becomes stronger, of course, for more intense activities, but is there already at rest. While with HRV we couldn’t see any link with VO2 max, even at rest or sleeping or anything. So, I think in general HRV might not be the ideal tool to monitor fitness level.

[Damien Blenkinsopp]: In terms of cardio fitness?

[Marco Altini]: Yes, in terms of cardiorespiratory fitness. And basically as a proxy to VO2 max, heart rate at rest seems to be a much better parameter.

[42:28][Damien Blenkinsopp]: Right. If someone is just looking at their resting heart rate, that’s also a standard in athletics and so on, people could watch that. And then you’ve basically built up a bit more on that, through your fitness index.

[Marco Altini]: Yeah. So I basically used that one and the energy expenditure normalized value together with some adaptation due to age, so that basically the value doesn’t depend on age.

So if your other fitness index tries to predict is just maximal heart rate, basically it tries to predict, for example, what would be your heart rate if you were running, even though you’re now resting and you do these activities in your life. And then that your sub-maximal heart rate and your maximal heart rate are basically depending on your age as well, right. So it will decrease over time.

And so I applied some corrections there to allow people of different ages to get values that they could compare.

[43:26][Damien Blenkinsopp]: Right, right.

So it’s all about normalization, right? Getting normalization right so that you can use it, which would mean that you can compare it against different people. Right?

So just before this call, I was saying hey my score is 60, what it is it like? Does that mean I’m fit or not, compared to you, you’re 70 and I’m like, damn I’m less fit than you. Right? So that kind of context, which is literally what people like to do, right?

[Marco Altini]: Yeah, I think so.

[Damien Blenkinsopp]: People want to be a bit competitive about this, and you know it’s part of team sports and so on. And people are into this stuff.

[Marco Altini]: Exactly. Because for every time if you look at VO2 max, for example, then it’s basically impossible to compare unless you have a person who is basically your age, your gender, and your body weight and possibly also your body fat. Then you can compare. Because otherwise there are too many parameters there.

[44:12][Damien Blenkinsopp]: So I wanted to use this as bit of a demonstration on what’s important in a biomarker if it’s going to be useful to us.

So one of the things you brought up, which is key here, is normalization so we can compare it to other people. There are different devices out there, but sometimes we can’t compare against other people effectively, because as you say it hasn’t been normalized. That’s one part.

What other things do you feel are important? Like if you just think of a biomarker, what would you be looking for to make it effective and useful to make decisions around?

[Marco Altini]: I think in general, it’s important that we always contextualize these things and this whole thing goes together with normalization. Normalizing parameters means also understanding in which context you were measured. So that’s something important.

Try to know everything around it and take care of taking measurements in isomeric conditions, because otherwise it’s easy to make the wrong conclusions just because some other factors are influencing what we are measuring.

[Damien Blenkinsopp]: It’s important to get some benchmarks.

[Marco Altini]: Yeah.

[Damien Blenkinsopp]: So we can understand the implications for our goals. So I’d like to see in the future if you have more data with your fitness app to see if you can compare the range of readings for different users, and things like that.

[Marco Altini]: I think in general, when we make these tools and we release them, for me it’s very interesting to look and take it step by step.

First you try to look at some relations that have been proven already in research, for example with heart rate variability apps, I let the people give me some reference points. So basically they can annotate not only when they train, what’s the intensity of their training and in the next lessons they will be able to add some more text around sleep, and all of that.

And that’s interesting because afterward because then, again, you can put the whole heart rate variability story in context with respect to how they trained and all of that. And then you know from some studies in literature, on maybe 100 people, that there is an important relation between HRV and training.

But then you can just scale that at the level of 1000 people and you start to find all of these relations. And then you can start exploring maybe a new one. So I think that’s quite powerful.

[46:37][Damien Blenkinsopp]: So another thing about this measure and measures that tend to be more useful is its stability. We’ve often come back to this in our podcast in different episodes, with different markers, whether it’s laboratory testing or whatever.

If a marker is moving around a lot ñ HRV is kind of moving around a lot, which can make it more difficult to use sometimes.

So, often you’ll see a pattern where one day it’s up and a little bit down the next day. It’s always kind of a jagged reading, so you have to kind of take an average of the last three days and things like that to get a stable reading on where your recovery is. Of course where there are the extremes and it really drops, then you’re like, “Okay this is a recovery day.”

But the thing about these biomarkers in general is it does help if they’re more stable and they’re moving along more steadily over time so you can make decisions on a more even basis. Because we’re not making decisions hour by hour in these cases where it’s fitness and health. It’s more like what am I doing this week versus next week, and so on.

[Marco Altini]: Yeah, the two cases also something with HRV, I think it’s very powerful because of that, because it can react that way to some stressors. But at the same time, it makes it very difficult to interpret sometimes. Because even consecutive tests can have very different values.

So that makes it quite difficult sometimes. But yeah. With heart rate, that’s a bit less the case. So indeed that’s one other reason why heart rate at rest is better for the cardiorespiratory fitness estimate, because it’s more of a stable parameter like cardiorespiratory fitness is. While HRV is very good as a parameter which you can use to understand how you’re reacting to certain stressors.

[48:22][Damien Blenkinsopp]: Yeah, that’s great. So different contexts. So I also know that you’re now working with data to help mothers with pregnancy.

[Marco Altini]: True.

[Damien Blenkinsopp]: So I wanted to touch on that and see what you’re doing there, because it’s an interesting area.

[Marco Altini]: Yeah. Well basically I’m working at the start-up at Bloom Technologies, where we are working on different aspects and the goal is to better understand pregnancy complications, by monitoring longitudinally different physiological parameters.

Since many of these complications, like for example pre-term birth, or gestational hypertension or gestational diabetes, are poorly understand, let’s say. And even in the developed world, even in the US, the percentage of pre-term birth is more than 11 percent and the whole medical community is, let’s say a bit struggling around how to try to bring this epidemic down.

So what we are doing there is to try to add some parameters to what we are measuring today. For example, uterine activity or even heart rate variability over time. And all we discuss now basically becomes important again because during pregnancy there are even more challenges because all these parameters change also because of pregnancy.

For example, heart rate increases by, let’s say, 10-20 beats during pregnancy because of course their heart needs to work harder because it needs to provide also for the fetus while it’s growing. So you have the additional context of knowing at which stage you are of the pregnancy, and trying to understand how all these parameters change.

So what we hope there is to be able to use this physiological data contextualized longitudinally over time, and try to get a better understanding of what is the impact, for example, of uterine activity and physiological stress, physical activity in all of these complications together with the variables which are already known to be affecting pregnancy.

[Damien Blenkinsopp]: So it strikes me this could be pretty interesting, because you might be able to alert someone to an issue over pregnancy. What kind of outcomes do you expect once this work is completed? What kind of goals would you have?

[Marco Altini]: So I think the first part would be to try to understand better what parameters are influencing some of these complications. And then for some of them there are interventions.

If you consider hypertension or diabetes, you can reduce activity or [51:02 unclear] and you need to know to be a bit more under control. Others are more complicated, for example pre-term birth; there is really no intervention there.

So still by understanding better what are the pathways there, and what is causing the issue, you could then after the second step try to see what is possible to do in terms of, for example, behavioral changes.

It is, for example, known that high stress has an influence on some pre-term birth rate, and on pregnancy outcomes in general. So if you can measure physiological stress, you could also have an intervention around some mediation practice or whatever it is that could lower stress, and then try to reduce complications around pregnancy with these kind of feedback loops.

[51:54][Damien Blenkinsopp]: Great, great, thank you.

I’m guessing it’s quite a ways off in terms of bringing something to market or things like that.

[Marco Altini]: Yeah we hope to have a product by the end of the year, around contractions. But again, let’s say more limited but at the same time that would allow us to collect data and work with hospitals and doctors to start to explore a bit more around this using also the power of having consumers with the device.

And consumer inserted data and data sets can grow much faster than with regular clinical studies while still providing clinically accurate data. So, we’ll be looking into that with some collaborations also here, for example with UCSF in San Francisco where they have a pre-term birth initiative that we are collaborating with.

[Damien Blenkinsopp]: Great, great thanks.

[52:50] So, where should someone look first to learn more about the topics we’ve talked about, VO2 max, or are there any presentations on cardio fitness or anything like that you know of, or maybe a book, that if someone was interested in this to get a better idea of this they could look up?

[Marco Altini]: There are some good resources, maybe I’ll just provide you some links. More on the physiological aspects. I think in general I’m happy to see the whole thing moving forward with this Stanford study.

So even just the website of this study, the MyHeart Counts study would be a good starting point to understand better these things. Because indeed we target as well healthy people. So giving a look at this up, it would be a good starting point for your cardiovascular health.

[Damien Blenkinsopp]: Great, we’ll put those in the show notes then.

[53:36] What are the best ways for people to connect with you, and to learn more about what you’re up to?

[Marco Altini]: I would say through my website. I try to keep it updated. Normally I’m very active. So if they just drop me a line or an email or something, I’ll get back to them for sure.

[53:52][Damien Blenkinsopp]: Is there anyone besides yourself you’d recommend to learn about cardio fitness and these area we’ve been talking about today?

[Marco Altini]: From the HRV stories, for sure all the people you had already on your show are great experts. For the fitness, I would need to think about it, because the research I’m doing, being a researcher now it means it’s going to take some time before it’s out. So I’m sure there are a couple of other groups that are doing great work there, but I haven’t seen much yet.

[Damien Blenkinsopp]: Okay. Well we’ll be linking to your stuff in the show notes of course, so people can check that out.

[Marco Altini]: Maybe I’ll think of something and I’ll get back to you on that.

[Damien Blenkinsopp]: Great, thanks.

[54:34] I’d also like to learn a bit more about your personal approach to body data. Do you track any metrics or biomarkers for your body on a routine basis, whether they be labs, and so on.

I know currently you’re using your own fitness index, correct? What are you doing in your life, or what have you been doing over the last year?

[Marco Altini]: So basically I’ve much of a maker approach. I use this stuff all the time when I make it because I want to try things first and it helps me understand the limitations a lot and where things can improve. So I’ve been using HRV for a long [time] because I have these apps around HRV and now I’m using also these ones about fitness.

In general, the only things I really track are my trainings. So I like to track that and see improvements there. And that’s why I also work around these variables which are connected to activity and fitness, and try to basically close the feedback loop, like with HRV, that gives you advice, and fitness that tries to quantify what your basically current level, what performance can you achieve.

[Damien Blenkinsopp]: Great, great thanks.

[55:45] Have you got any insights, like from the data you’ve collected, have you got an insights about your biology? Have you made any changes to behavior, or taken some kind of actions?

[Marco Altini]: No. I haven’t yet. It’s not that I didn’t get any insights, but I think it’s important to track first for very long periods. Meaning a year at least before you can start making changes.

Because so many other parameters affect our physiology and performance, especially if I consider training there are months where everything looks the same. Like maybe I haven’t traveled much, and I kept my diet the same, and my stress at work is pretty much the same. And I think I haven’t over-trained, but still there are some weeks where you don’t perform very well.

So it would be sometimes easy to make the wrong conclusions if you tend to make too many changes. So I think it’s good to track for very long periods, even HRV, to get all the values you see. And then you look afterward how your training had an impact and all of that. And then you try to make adjustments.

Maybe around HRV I am making adjustments, like I tend to follow now what I see there. You find something very interesting things, like sometimes you can spot you are sick before you actually realize you are sick. You do your test in bed because your HRV is like…hugely affected by that, for example like even just a fever or something.

Maybe in the morning you don’t just feel particularly well, but it seems just a regular day. And then your HRV is terribly low, and then the day after you’re sick. And that’s quite interesting to see.

[Damien Blenkinsopp]: I definitely rely on it. I’ve seen that a number of times. If it really drops, then I’m like, “Uh oh.î I’m going to get some vitamins, liposomal vitamin C and stuff like that to try and void the crash the next day. Or minimize it a bit. So I think it is pretty useful like that.

[Marco Altini]: Yeah, it’s quite interesting.

[57:41][Damien Blenkinsopp]: Okay, so what would you number one recommendation for someone trying to use data to make better decisions about their health or performance or longevity?

[Marco Altini]: Be consistent. Don’t expect short term miracles but keep doing it, keep tracking. Try to understand at your personal individual level what is affecting these variables and then slowly start to make changes and bring to mind how these changes affect the rest. Let it be, I don’t know, performance or whatever variable that matters to you.

[Damien Blenkinsopp]: Yeah, I think you make a great point because as you were saying, there are so many different variables which we can’t keep track of. Especially in our busy lifestyles today. Whether it’s travel, a different location, different food, different sleep conditions, or maybe just different supplements and other things if we’re experimenting things. There are a lot of different variables that can influence it. So that makes a lot of sense.

So Marco thank you so much for your time today. It’s been a great chat.

[Marco Altini]: Thank you Damien.

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An in-depth look at using heart rate variability biofeedback with slow breathing to reduce stress, enhance athletic performance and provide therapeutic support for some chronic health issues.

Heart rate variability biofeedback is being used primarily to reset the nervous system and thus as an antidote to different types of stressors. These include modern-day chronic stress, aka the all-time-on syndrome, or infections or other problems in our lives.

In this episode we compare the use of breathing techniques to other tools like meditation to improve HRV (Heart Rate Variability), and the use of biofeedback to optimize the benefits.

Biofeedback enables us to learn what yogis historically spent decades learning in a matter of weeks. And the applications are multiple. It can be applied to improving athletic performance, productivity, health issues such as headaches, irritable bowel syndrome, insomnia, asthma, inflammation and on and on.

It turns out that everybody has their own unique pace, where breathing in and breathing out at that pace produces the biggest peaks and valleys, the exact right phase angle between respiration and heart rate, and when you go into that particular rhythm, it seems to have tremendously beneficial effects. Again, we often see this as a brand new idea that’s 2500 years old because this is exactly what these yogis were doing.
– Richard Gevirtz

For the HRV biofeedback topic our guest is Professor Richard Gevirtz, PhD, professor of health psychology at Alliant International University. He has been working in HRV biofeedback for nearly 30 years and he’s published over 40 papers on biofeedback during that time in areas such as mind-body feedback, stress disorders, clinical protocols for the biofeedback, anxiety disorders and autonomic control. This was a great interview; I thoroughly enjoyed it. I hope you enjoy it too.

The episode highlights, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

What You’ll Learn

  • The early days of biofeedback – key discoveries in conscious control over autonomic functions of the body (6:12).
  • How the science on the benefits and mechanisms of various yogi techniques needs to improve – to produce more quality studies and reliable data (11:05).
  • The degree of complexity in HRV biofeedback and the applicability of various beat-to-beat analysis in studying mechanisms of stress response (14:19).
  • Optimizing breathing and heart rate rhythms has beneficial effects on the cardiovascular system (19:26).
  • Why standard metrics do not apply for slow breathing, because this category is a low frequency range of approximately 4-7 breaths per minute (26:54).
  • Overviewing the ups and downs of available beat-by-beat biofeedback devices (32:25).
  • An average training session aimed at determining optimal breathing frequency during slow breathing. How to optimize measuring equipment and make people feel comfortable during the HRV tracking exercise (42:31).
  • Performance benefits of practicing breathing exercises, with examples in sports and music (46:33).
  • For optimal results, during practicing slow breathing you should be non-judgmental and self-observant at the same time (50:09).
  • How the brain and heart integrate physiological feedback in the body and how this system is negatively affected by anxiety and stress (52:35).
  • Positive effects on gastrointestinal health in kids with inflammatory bowel disorders, who practice slow breathing techniques (57:55).
  • In most studies on depression, improvements in HRV biofeedback are accompanied with beneficial effects (1:00:01).
  • Slow breathing training helps for anxiety and urge – control, by inhibiting stress response centers in the brain (1:03:52).
  • Data on cortisol (the stress hormone) indicates beneficial effects of slow breathing practice in fighting stress (1:04:30).
  • When practicing meditative slow breathing, it is important to measure EEG waves in low frequency ranges – in order to clearly demonstrate beneficial effects on heart performance (1:05:16).
  • Gratitude and compassion mindfulness exercises are broadly related to HRV performance, but optimizing slow breathing is a practicable and improvable skill to be learned and trained (1:08:47).
  • In the future, the team and Prof. Richard will continue to research outcomes of HRV studies, physiological mechanisms of slow breathing, and standardizing yoga breathing practices by beneficial effects (1:10:48).
  • How to best obtain information of Prof. Richard’s research and career (1:14:27).
  • People and lines of research related to Prof. Richard’s interests. Additional practical advice on integrating HRV biofeedback with your performance goals (1:14:27).

Prof. Richard Gevirtz

Tools & Tactics


  • HRV Breathing: Modern science is increasingly focused on beneficial effects of meditation and slow or diaphragmatic breathing techniques – practiced at the pace of 4-7 breaths per minute. During slow breathing, heart rate and breathing rhythms synchronize – in a way that produces resonance in the autonomic nervous system. This concept is known as a meditators’s peak. The unique slow breathing pace at which it occurs in different individuals (for most people between 5.5 – 6 breaths per minute) can be determined using HRV biofeedback tracking tools. When tracking Low Frequency (LF) HRV ranges (see below), the meditators’s peak occurs as a single spike of great magnitude (in graphical form) and is followed by smooth overlaps between the peaks and valleys of waves representing breathing and LF HRV rhythms.
    Over time, slow breathing exercises produce flexibility in the autonomic nervous system. Essentially, practicing breathing at a specific, disciplined, rate synchronizes respiratory and cardiac systems to increase resilience to physical or psychological stress, improve autonomic balance, and sharpen mental clarity. These tools can be used to fight against stress related medical conditions such as Irritable Bowel Syndrome (IBS), hypertension, depression etc.
  • Acceptance and Commitment Therapy (ACT): Prof. Gevirtz has successfully applied this psychological therapy in his practice. A recent scientific review of all available research on ACT concluded that it is more effective than placebo, or standard treatment, in dealing with anxiety disorders, depression, and addiction.



  • Heart Rate Variability (HRV): HRV is the measure of the change in the heart’s rhythm over time based on changes between sympathetic and parasympathetic activation. HRV was previously covered in the context of managing stress using HRV in Episode 6 with Ronda Collier, in using hormesis to improve HRV in Episode 8 with Todd Becker, and in using HRV as a biomarker for longevity in Episode 20 with Dr. Joon Yun.
  • Time-Domain HRV

  • Standard Deviation of Normal to Normal R-wave Beat (SDNN): The most statistically simple measure of HRV – simply measuring beat-to-beat variability.
  • Root Mean Square of the Successive Differences (RMSSD): A measure used to calculate HRV that has proven to be reliable and is used in a lot of research studies. An integral measure that seems to be a little bit more dominated by the parasympathetic nervous system, compared to SDNN.
  • Frequency-Domain HRV

  • HRV may be broken into frequency components that compose the overall variability. Low Frequency (LF) is association with sympathetic activation; High Frequency (HF) is associated with parasympathetic activation. Frequencies of different rhythms can be detected over time in the heart rate. How much any of the frequencies is present in overall variability is indicative of heart performance and factors which influence this performance. For example stress is associated with high LF with respect to HF (high LF/HF ratio).

Lab Tests, Devices and Apps

    Biofeedback Devices

  • HeartMath: The company has developed products for tracking HRV. Devices include emwave2 and Prof. Gervitz’s preferred device – Inner Balance for iOS.
  • My Brain Solutions: The company offers products which track HRV including MyCalmBeat.
  • Muse: The Brain Sensing Headband: This device provides brain feedback data and allows users to determine when they are in a fully meditative state.
  • Breathing Timing Apps

  • MyCalmBeat App: Over 30 brain exercises for training slow breathing and improving HRV in managing stress.
  • Breathe2Relax: This is a portable stress management tool which provides instructions and practice exercises for using slow breathing techniques and managing stress.
  • Breath-Sync Music CD Suite: The suite includes six CDs with slow-breathing music, each at a different rate (from 4.5 to 7.0 breaths per minute).
  • Multi-Channel HRV Biofeedback

  • NeXus-4 by Mind Media: This instrument can be used to simultaneously track various biofeedback signals coming from photoplethysmogram (PPG) sensors. These sensors optically determine heart rate by illuminating the skin with the light from a light-emitting diode (LED) and then measuring the amount of light transferred to an opposite end of a finger – clipped sensor. Changes in light are indicative of changes in blood flow – which result from changes in hearth beat rhythm.
  • Stress Control Suite by Thought Technology: This software integrates information from multiple sensors relevant for tracking HRV and autonomic nervous system functionality. The Stress Control Suite works with the ProComp2, a physiological monitoring device which can be plugged to Temperature Sensors and Skin Conductance Sensors.
  • Multiple Channel ECG reader by J&J Engineering: This product connects to a computer and is able to monitor ECG, skin conductance, temperature, and respiration rates, at the same time. Price: $1,995.
  • HRV Analysis Software

  • Kubios HRV

Other People, Books & Resources


  • Peter J. Lang, PhD: A research scientist who was one of the founders in the field of psychophysiology (linking psychological phenomena with physical states of the body).
  • Our guest, Prof. Gevirtz, collaborated with Marks Schwartz PhD, Paul Lehrer PhD and with Dr. Stephen Porges during the early days of biofeedback.
  • Dr. Robert Freedman: Because of his interests in Raynaud’s disease, Dr. Freedman experimented with biofeedback as a way for people to learn to control blood flow in cold areas of the body – as a therapeutic means.
  • Neal Elgar Miller: An American experimental psychologist whose studies showed that animals and people could control all kinds of autonomic functions. Numerous studies of his have not been able to be replicated, leading to controversy. Regardless, Neal E. Miller’s legacy stems form inspiring future and current researchers to dig deeper into psychophysiology and behavioral studies.
  • Dr. Elmer Green has traveled to India and done extensive research on the physiology of yogis. He discovered that, through meditation and slow – breathing techniques, yogis could control a range of autonomic phenomena. Notably one yogi could warm one ear and then switch to warming the other, at will.
  • Laura Schmalzl PhD: Prof. Gevirtz recommends a recently published scientific review article by Laura Schmalzl on the topic of neurophysiological and neurocognitive mechanisms underlying the effects of yoga-based practices.
  • Dr. Ary L. Goldberger: A beat-to-beat heart rate is characterized by many different oscillators that are contributing to a healthy pattern. Dr. Goldberger is a pioneer of analyzing complex patterns in cardiology and in detecting how these vary in different heart diseases.
  • Lionel Messi: A world famous football player, currently playing for FC Barcelona. His coaches optimize his training using the gold-standard for HRV tracking – every morning in bed, right after waking up.
  • Prof. John Gruzelier: A researcher who makes use of brainwave feedback and slow-breathing techniques to bring benefits for recitals and dance performers.
  • Prof. Mihaly Csikszentmihalyi: A leading researcher in the psychology of flow (aka. optimal experience).
  • Tim Harkness: A club psychologist for FC Chelsea. His approach includes positive psychology, cognitive perception training, and psychophysiology.
  • Evgeny Vaschillo PhD: A Russian cosmonaut physiologist who started studying hearth rhythms in the very low frequency range – at approximately 3 breaths per minute.
  • Dr. Luciano Bernardi: At Italian cardiologist arguing that music offers beneficial effects in managing cardiovascular disease. Our guest shares the story of how Dr. Bernardi traveled to mountains in Bangalore accompanied by twelve yogi. He discovered the yogis’ slow breathing techniques had significantly increased their baro reflex (the ability to withstand high altitude without experiencing symptoms of altitude sickness).
  • Mark Stern: One of Prof. Gevirtz’s students who students who created a video to explain the basics of HRV Biofeedback and its Applicability.
  • Inna Khazan PhD is a clinical psychologist using mindfulness and biofeedback in her therapy. Prof. Gevirtz recommends her book on combining mindfulness with biofeedback (see below).
  • Dr. Kevin J Tracey: A neurosergant who is the president and CEO of the Feinstein Institute for Medical Research. His research focuses on inflammation and how neurons control the immune system.
  • Rollin McCraty PhD: Executive Vice President and Director of Research for the company HeartMath.


  • Western Association of Biofeedback and Neuroscience: Formerly called the Biofeedback Society of California, was founded in 1974 and is the oldest and largest state neurofeedback biofeedback society.
  • Association for Applied Psychophysiology and Biofeedback (AAPB): AAPB’s mission is to advance knowledge about applied psychophysiology and biofeedback, to improve health through research, education and practice.
  • Mayo Clinic: Mayo Clinic is a nonprofit medical practice and medical research group based in Rochester, Minnesota.
  • The Wingate Institute: An interdisciplinary research unit focusing primarily on biofeedback and psychophysiology of gastrointestinal diseases. Notably, their research has shown that slow breathing exercises protects patients from lowered esophagial pain thresholds, thus lowering the conscious perception of pain.


Full Interview Transcript

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[DAMIEN BLENKINSOPP]: Richard, thank you so much for joining us today.

[RICHARD GEVIRTZ]: Glad to be here.

[DAMIEN BLENKINSOPP]: I wanted to get a quick background behind what you do. How did you learn to do what you do, these studies and this area; how did you first get into it and learn to do it?
[RICHARD GEVIRTZ]: Well I started as an undergraduate studying with a famous psychophysiologist named Peter Lang, who was one of the founders of the field of psychophysiology, which is basically different from neurophysiology because we’re looking at physiological measures indicating psychological parameters. In those days we were measuring heart rate, but not beat-by-beat heart rate, just average heart rate, and muscle tension, temperature and respiration.

Then I went to grad school and got waylaid a little bit into another topic, but eventually I came back to psychophysiology and began working. I was in Minnesota at the time and I was near the Mayo Clinic, and I ended up working with a guy who’s been a lifelong friend, Marks Schwartz, at Mayo Clinic and doing biofeedback. It was the beginning days of biofeedback.

In those days we were doing just muscle tension and temperature and breathing, not even heart rate in those days. That was interesting; we were doing work on chronic pain mostly, and then relaxation techniques with finger temperature. I did that for a number of years but became a little unhappy with it because it seemed very limiting.

I had a background in heart rate, and as the technology got better, we realized that we could measure heart rate in a much more sophisticated way. Actually, in the beginning, I was collaborating with Paul Lehrer, my colleague at Rutgers University, and we were fascinated by this. Also we were good friends with Stephen Porges, who is this Polyvagal Theory guy. We were fascinated by this idea that the action wasn’t in the sympathetic nervous system as much as in the parasympathetic nervous system for day-to-day stress. That went against everything we had been doing up till then, which was really calming down the sympathetic nervous system.

So, as the technology built, and we realized it was really an incredible amount of information in the beat-by-beat heart rate, he and I began developing this idea of looking at beat-by-beat heart rate and feeding it back to people.

At the same time, in cardiology, the measurement of the beat-to-beat heart rate was growing rapidly, and so we benefitted a lot from all of the cardiology research showing a healthy heart as a very complex, somewhat chaotic-looking pattern to them, and that represented mostly the parasympathetic nervous system.
(0:06:12)[DAMIEN BLENKINSOPP]: Great. To take a step back a bit, what is biofeedback and what are the benefits that you’re seeking through using that?

[RICHARD GEVIRTZ]: Biofeedback, in general, is feeding back physiological information to a client or a subject and having them try to modify their physiology based on what they see, based on either wiggly lines on a screen or some analogue – a rocket ship going up or a train moving, or some other visual or other signal.

In the early days, what we were doing was teaching people to relax their muscles more profoundly than they might be able to do naturally, and we did that by feeding back information from voluntary muscle activity from electromyographs. Then we used finger temperature because it turned out that by learning to warm your hands, you could shut down the sympathetic nervous system. The sympathetic activity produces vasoconstriction. As you learn to vasodilate, it generally accompanies relaxation.

[DAMIEN BLENKINSOPP]: People would focus on their hands?

[RICHARD GEVIRTZ]: Yeah, they would focus on mental techniques to warm their hands.

[DAMIEN BLENKINSOPP]: It’s interesting.

[RICHARD GEVIRTZ]: And it turned out that they could both cool and warm their hands at will. A colleague of ours, Bob Freedman, in Detroit, was interested in Raynaud’s disease, so he was starting to look at biofeedback as a way that people could learn to warm their hands, even without getting relaxed they could learn to vasodilate. He studied the mechanisms of that and actually found fairly detailed mechanisms of how people could warm and cool their hands with different mechanisms. But they could definitely do it; medical students, even while playing a game of bridge, they could warm or cool their hands when a signal told them to do it at, will. Not a lot, but to some degree.

Everybody was fascinated by the plasticity idea that people could really control these supposedly non-controllable autonomic phenomena. So actually the original impetus was Neil Miller’s studies in ’69 that showed that animals and people could control all kinds of autonomic functions, although most of that has not been able to be replicated, interestingly enough. But it’s a famous study in ’69 and we knew Neil Miller. He was a great pioneer in his field. So even though it hasn’t been replicated, it’s still got us all thinking about control of autonomic phenomena.

At the same time, a colleague, Elmer Green, went to India and studied yogis, and showed that yogis have remarkable control of autonomic function. Though he didn’t exactly know how they did it at the time, they certainly could do all kinds of things. They could warm one hand and not the other hand, they could warm one ear and not the other ear, and they could do a trick that looked like they were stopping their heart, which is actually just a muscle tension that hid the ECG.

[DAMIEN BLENKINSOPP]: So the ECG wouldn’t pick it up because of the way they were beating their heart?

[RICHARD GEVIRTZ]: Yeah. It looks like they’re actually stopping their hearts – they weren’t. But it’s still pretty amazing. And they also had great control over heart rate and they could control heart rate, so it looked like maybe people could learn to control heart rate, and that was our first foray into that idea.

[DAMIEN BLENKINSOPP]: Did you ever look into how the yogis had learnt that? Was it meditation or mindful?

[RICHARD GEVIRTZ]: Purely meditation, yeah. It was various kinds of yogic meditation with a lot of breaths, a lot of pranayama.

[DAMIEN BLENKINSOPP]: Was this like the fire breathing, the fast breathing and things like that?

[RICHARD GEVIRTZ]: All kinds of breathing techniques: fast breathing, nasal, alternation with nasal breathing, slow breathing, but the thing we eventually discovered was if we asked the yogis to do what they do to get calm and centered, whatever language we could use for that, they always did the same thing. They always breathed very slowly, somewhere between four and a half and seven breaths a minute – whatever breath rate they chose, they always used exactly the same breath rate, within a half a breath, and they could do it even during distraction.

One of our colleagues had this one yogi who had put skewers through his tongue and through his arm and his neck, and still maintained this exact breath rate through the whole thing.

[DAMIEN BLENKINSOPP]: Wow. Was he making new holes in himself with those?

[RICHARD GEVIRTZ]: Yeah, little tiny holes, but he could prevent bleeding. It wasn’t a fake because I was right there next to him and I felt those skewers and I saw him do it. I think he learned certain places to put them that didn’t bleed and would quickly close up again, but they could do this without any outward sign of pain, without any physiology changing, is just remarkable.

We realized that there was some potential for control and that set us off on this pathway.
(0:11:05)[DAMIEN BLENKINSOPP]: I actually used a machine where they look at the blood flow in your forehead. I don’t know if you’ve seen that it’s a biofeedback mechanism – you can play this little computer game and it will go in the right direction when you’re increasing the blood flow.

[RICHARD GEVIRTZ]: Yeah. The question about that technique is whether it’s really just measuring forehead and dura blood flow, maybe peripheral blood flow, or is it really going deeper into the brain to measure cortical blood flow, and I think that’s still to be decided. The claims are that you’re getting the first centimeter of the cortex – I don’t think that has been shown, myself. But something varies, there’s no doubt about it, and people can learn to control it.

Blood flow was one of those techniques that yogis could control. Remarkably sometime there was one yogi who could make one ear get very warm and the other ear stay the same and then he’d switch ears. How he did that, he could never tell us. He just willed it. But that’s pretty remarkable. Physiologically, you’re not supposed to be able to do that. There’s no evolutionary reason why we should be able to control an autonomic function like blood flow, so somehow the brain could learn to do this through some remarkable meditative techniques.

[DAMIEN BLENKINSOPP]: This is pretty spectacular. I’d read a lot of the yogi books and some of the books on the science of yoga, and I wanted to try it but I wasn’t sure there were actual benefits and I didn’t know what the benefits were, and it went through all the history and stuff – quite interesting to see that some of that matches up, that’s spurred on your interest in the area.

[RICHARD GEVIRTZ]: Right. Actually we’re trying to encourage better science, because they think they know it all and they can cure everything, and I think the chances are that they are definitely on to some very remarkable things, but others probably not.

[DAMIEN BLENKINSOPP]: Yeah, because it’s interesting because it’s split into different types of yoga and all of this, and which came from the actual practices. I understand that some people injure their lower backs and things like that, so there are some parts which are seen as not good and other parts, which as you say, could be good. So there’s a way to go to figure that out.

[RICHARD GEVIRTZ]: It’s very tricky for science because they don’t have standardized methods. We just got a paper from a group about a kind of a yoga called reflective exercise. It’s got some Indian name and it’s claiming fantastic results with athletes. Here it’s just a completely different one – they use reverse diaphragmatic breathing – and with all kinds of claims, with really not much science behind it.

I’m an associate editor of the journal Applied Psychophysiology and Biofeedback and we try to encourage people to send us some good scientific papers. We would love to see what the mechanisms are. There is just a recent paper coming out in Frontiers, looking at the neurophysiological mechanisms of yoga – a pretty extensive review by a woman named Schmalzl. There’s lots to be learned, that’s for sure, but I think it’s an area that will be studied more frequently.
(0:14:19)[DAMIEN BLENKINSOPP]: Great. Thanks for the reference on that paper, too. That will be interesting to read.

So you’ve been focused on the heart rate variability biofeedback for a while. What is that in comparison to the other stuff we’ve been talking about?

[RICHARD GEVIRTZ]: Firstly, the important point for the listeners is that heart rate variability measurement is completely different than heart rate variability biofeedback. The measurement is a very big field, very dominant in parts of cardiology, and the underlying idea is that healthy hearts have tremendous complexity in their patterns of beat-to-beat activity – and you have to actually look at a beat-to-beat to see this. If you go to the gym and do your average heart rate, that doesn’t pick it up at all.

A beat-to-beat healthy heart rate is characterized by great amounts of complexity – many different oscillators that are contributing to the pattern. For some heart disease things, you need a non-linear message to look at these really complex patterns. Ary Goldberger is pioneering this in cardiology and has amazing results with different heart disease, in terms of seeing how it varies.

The measurement is of interest to us because we do measurements on people with different disorders. The disorders we are interested in are more psychophysiological or stress-related disorders and they do show up with poor heart rate variability quite often.

[DAMIEN BLENKINSOPP]: Are we talking about RMSSD here?

[RICHARD GEVIRTZ]: Yes. There are three classes of measurement. One is called time domain measures, which are fairly simple, they just look at the beat-to-beat variability. The most common one is SDNN, standard deviation of the normal to normal R-wave beat. A little more sophisticated and one of the same type is called RMSSD, root mean square of successive differences. The difference between the two is that the second is an integral measure that seems to be a little bit more dominated by the parasympathetic nervous system. SDNN is simply all forms of variability, it’s just the standard deviation of beat-to-beat differences.

It’s quite simple really. You just get a column of interbeat intervals in milliseconds and take the standard deviation. That’s still very widely used and is a powerful epidemiological measure. RMSSD is a little bit more sophisticated because it picks up a little bit more of the parasympathetic nervous system.

Then there are frequency domain measures, a second class of measures, and that’s where you look at what the frequencies are of different rhythms over time in the heart rate. It gets a bit more complex then. So you have to print out a sequence of beat-to-beat heart rates and then look at the frequency characteristics of them, and those frequency characteristics then can be sorted by how much of each frequency. The advantage to that is that in one realm, what’s called high frequency power, is a pretty good analogue to the vagal tone.

The tenth cranial nerve is the vagus nerve, which is the parasympathetic nerve that controls heart patterns. At rest, it’s the dominant source of heart patterns. By being able to measure the amount of vagal tone, we can look at things that are of interest to us, especially psychophysiological disorders or anxiety disorders, depression, because those things are all diminished in those disorders.

[DAMIEN BLENKINSOPP]: So better vagal tone is better, more control?

[RICHARD GEVIRTZ]: Exactly, yes, good vagal tone is, in general. A rebound vagal tone, like in asthma, which is too much vagal tone and it shuts down the airways, but that’s just a poor amount of flexibility in the autonomic nervous system.

The goal is very flexible, resilient, autonomic nervous system; not necessarily more tone overall. We do see less vagal tone, however, in a number of disorders.

[DAMIEN BLENKINSOPP]: I think another scenario where high vagal tone may not be a good thing is adrenal fatigue – we’ve discussed it on the show before.

[RICHARD GEVIRTZ]: Yeah, that could be, and as I say, asthma, if you get a sympathetic surge followed by a giant parasympathetic rebound, it shuts down the airways and that’s not healthy. There are some situations like that. Some kinds of stress are vagal stress. For instance, if you show somebody a video of a fake shop accident, where the shop teacher is putting a piece of wood through a circular saw and we see him just about to saw off his finger, people rate that as very stressful, but they don’t get a sympathetic surge, they get a parasympathetic surge from that.


[RICHARD GEVIRTZ]: Similarly for a vasovagal response, people faint when they see blood or needles; that’s a parasympathetic response, not a sympathetic response. So the system is adaptive to what’s important. The vagal system is trying to preserve blood and shut things down, but that can be a stressful response too, so we don’t want you to just think stress is sympathetic.

(0:19:26)[DAMIEN BLENKINSOPP]: Right. In terms of the heart rate variability mechanism you’re looking at, which approach have you been using?

[RICHARD GEVIRTZ]: The measurements we use are the same as everyone else. I’ll tell you an anecdote – it’s a fun anecdote. Paul Lehrer went to Russia; went to visit his son who works for the state department, and there met some people doing some of this heart rate stuff. They had kids breathing very slowly and improving their vagal tone in front of computers in St. Petersburg. He couldn’t understand why that would work because it seemed like it would kill them if they had asthma. These are all asthmatic kids – but they were getting better.

He tried to understand that better and eventually that led him to a guy named Evgeny Vaschillo, who was the cosmonaut physiologist. He was observing heart rates and respiration rates in the cosmonauts. By some chance, one of the cosmonauts was a bit of a meditator and every day in space he would suddenly see these patterns of heart rate that were completely unusual. Big peaks and valleys, very slow big peaks of waves and valleys. Again, he called up and thought the guy was dying or something, and he said, “No I’m just meditating.” So, luckily he was also an engineer and a physiologist and he began studying these patterns.

At the same time, we were doing the same thing, but we didn’t quite understand it. But he helped us understand that at certain slow breathing rates there is a resonance produced in the cardiovascular system, between several different oscillatory systems. The main one is called respiratory sinus arrhythmia. It’s like a brake accelerator and every time you breathe in, the brake goes off; when you breathe out, the brake goes on. If you think about it, it makes sense: the brake goes off, heart rate speeds up; when the brake goes on, heart rate slows down.

Why wouldn’t you want heart rate to be speeding up when you have oxygen available for gas exchange, and then when you’re breathing out, there’s no oxygen available? Actually it saves you something like 350 million heartbeats over a lifetime. This rhythm is called respiratory sinus arrhythmia, RSA, and it’s a normal pattern that we can see in a normal resting heart rate. But when you breathe somewhere between four and a half and seven breaths a minute, that pattern becomes greatly exaggerated.

What Vaschillo figured out, and we’ve built on, was that at those rates, you’re getting the phase angle between the baroreceptor, the blood pressure rhythm in your body, and the breathing rhythm in your body at exactly a 180 degree phase angle. What’s happening is you’re breathing in and heart rate is going up, then it’s going up even further because blood pressure is at the exact right angle for blood pressure to go down to make heart rate go up; and then when you breath out, the opposite happens in the other direction. So, these unexplainable shifts in the cosmonaut, where it was going from 65 beats a minute to 95 beats a minute in each rest cycle – giant peaks and valleys.

[DAMIEN BLENKINSOPP]: So you can’t get that by – people would think based on the description you gave – I breathe in and it goes up? So I can’t take a really, really big breath, hold it for 20 seconds and breath out, and get a higher peak and trough.

[RICHARD GEVIRTZ]: No because the timing isn’t right. It’s like a metronome, and you have to push on both ends of that metronome to make those big peaks and valleys. You’ve got to get exactly the right pace to do that.

There is an artifact in there. When you breathe more deeply, you do produce an artificial pressure that does affect the heart a little bit. It’s not really the one we’re interested in. We’re interested in what happens during restful breathing at certain paces. That’s where the benefits seem to come. In fact, the danger of really deep breathing is people hyperventilate and then that has negative effects on them. So we really try to prevent hyperventilation at all costs.

It turns out that everybody has their own unique pace, where breathing in and breathing out at that pace produces the biggest peaks and valleys, the exact right phase angle between respiration and heart rate, and when you go into that particular rhythm, it seems to have tremendously beneficial effects. Again, we often see this as a brand new idea that’s 2500 years old because this is exactly what these yogis were doing.

These yogis have remarkable cardiovascular systems. None of them are hypertensive – we’ve never found one that’s hypertensive. If you take them to high altitude, none of them get altitude sick. A colleague Luciano Bernardi, a cardiologist in Italy – it’s a funny story – he went to Bangalore and found twelve yogis and got them to agree to go up to high altitude. The first thing he found out is that yogis are prima donnas, they wanted to be pampered. He thought they were going to be really stoic and not care what material – no, they wanted a certain kind of cot, a certain kind of food. So as they drove up to the Himalayas, the Italian crew was all getting altitude sick, having a tough time, and these guys are just complaining about the food!

We realized that what they’re doing is they’re strengthening the baro reflex tremendously, by 30 percent. Practicing every day, you strengthen this reflex in the cardiovascular system that has really powerful benefits for cardiovascular health, and that’s why they all have fantastic cardiovascular health because they breathe tons of time at these slow breath rates. They also do other breathing techniques too, but they do – do this as well.

[DAMIEN BLENKINSOPP]: Are there any studies on heart disease, cardiac issues in yogis?

[RICHARD GEVIRTZ]: These yogis don’t have heart disease, but of course they’re also vegetarians, who knows.

[DAMIEN BLENKINSOPP]: Right, there are other co-factors.

[RICHARD GEVIRTZ]: Yeah, lots of factors, but it’s unknown in these people that do this. There is a lot of evidence now in cardiac rehab that people that get a lot of vagal stimulation – nowadays the big money is in vagal nerve stimulators – that’s healing to the heart. There’s a study at Cleveland Clinic where they’re using the HRV biofeedback instead of left ventricular assist devices for people who are getting a transplant, and when they harvest the heart for the transplant, the old heart is much healthier than they would have expected. It’s well known that vagal input to the heart repolarizes the cells and is healing to the heart and overloading sympathetic system is very detrimental to the heart.

[DAMIEN BLENKINSOPP]: I don’t know if you have done studies, but we tend to be higher sympathetic basis? Everyone talks about it but I was just wondering about the studies and if we’ve actually looked at that?

[RICHARD GEVIRTZ]: The more chronically stressed your life is, the more sympathetic dominance there is. That generally plays out in poor cardiovascular health. The veterans coming back from the Gulf Wars have horrible looking cardiovascular systems. They look like they’re 70 years old – and they’re going through 18 months of chronic stress – and that’s really bad for your heart. So there are efforts underway to try to teach them techniques to prevent that.

(0:26:54)[DAMIEN BLENKINSOPP]: Coming back to the metrics you’re using.

[RICHARD GEVIRTZ]: The metrics don’t apply anymore when you’re doing slow breathing, that’s a hard thing for people to understand. So when you’re breathing normally, you want most of the activity to be in the high frequency – between 12 and 20 cycles per minute. That’s what’s called high frequency HRV. But when you’re breathing slowly, you’re purposefully moving out of that, into a lower frequency range. At rest, a low frequency range is indicative of poor vagal tone and high sympathetic activity, but when you’re breathing slowly, you’re artificially moving into that period of time during that slow breathing.

It’s like any kind of exercise. If you measure someone’s physiology when they’re exercising physically, they look like they’re quite sick during the exercise – their heart rates are flying high, they’re sweating – but, of course, we know that when they stop, then everything gets more resilient and more fit. The same thing is true for the autonomic nerve system. This is a kind of exercise for the autonomic nervous system. On a regular basis, you produce quite a lot of resilience, flexibility and health in that system.

The metrics fall apart completely when we do the biofeedback. We have to completely ignore them and start looking at a different sort of metric then. So then what we want is actually all the activity in the low frequency range, which is in the four to seven range. The activity we look at, there’s one known as meditator’s peak in that range – it’s a single peak of great magnitude in that low frequency range. If that was your normal breathing, that would be a sign of ill health, but during this slow breathing, it’s a sign of accomplishment, of being able to do the technique.

[DAMIEN BLENKINSOPP]: So it’s a specific frequency? Basically, nearly all of your heart beats are within this specific frequency range?

[RICHARD GEVIRTZ]: It’s exactly where you’re breathing. Let’s say you’re breathing in five breaths a minute, then it will be a little less than 0.1 Hz. If you’re breathing in at six breaths a minute, it will be exactly 0.1 Hz. If you’re breathing in seven, it will be a little bit higher than that, or something in-between those. That’s exactly what you see – breaths dominate that peak and then you want that peak to be the exclusive peak in the heart rate, and as high as it can be, during slow breathing.

[DAMIEN BLENKINSOPP]: Does it matter exactly where it is?

[RICHARD GEVIRTZ]: Yeah, for each person it matters because they have to find their resonance frequency. What heart math calls the point of coherence, we call resonance frequency. We think coherence is not exactly the right word because it means two things going together. It is two things aligning together – breath and heart rate – but they don’t measure breath, so we think really what you are doing is producing true physical resonance in the system between the baroreceptors and the breathing rhythms, and that’s where the big benefits come during that slow breathing.

[DAMIEN BLENKINSOPP]: Is it different for different people?

[RICHARD GEVIRTZ]: Yeah. We get some people at four and a half breaths a minute, that’s where their peak is; some at five; some at five and a half; some at six; some at six and a half; some at seven. We’ve done various studies to see where the frequencies are. They tend to be in the five and a half to six range for most people. Smaller people tend to have a little bit higher frequencies, very tall people have lower ones – it’s like a violin versus a cello, with different resonances. That’s not a perfect relationship.

What we do in the biofeedback is we test at every breathing frequency. With the other systems, what you do is just trial and error to try and find something that produces the most coherence. We actually systematically don’t do that; we systematically go through in some order. I like to start at seven and we do a few minutes of breathing at seven, then six and a half, then six. At some point, the pattern falls apart – it’s too slow – so we go back up another half beat until we find somewhere within a half a beat of the proper frequency for that person.

[DAMIEN BLENKINSOPP]: Where they’re getting their highest peak and trough?

[RICHARD GEVIRTZ]: Exactly, and the phase angles are correct, and it’s also the one with the smoothest heart rate patterns. That does show up – at our school they’re using a seismograph just to look at the pulse beats, but I think it does hold up that the smoothest, biggest peak-valley differences is usually where it will be.

[DAMIEN BLENKINSOPP]: Does that work with smooth breathing as well?

[RICHARD GEVIRTZ]: Yes, and we try to teach diaphragmatic breathing – smooth, restful, diaphragmatic breathing works better. If you overdo it, you hyperventilate and then you lose the effect. If you can breathe with your diaphragm, it’s much easier to breathe more slowly if you actually get your diaphragm in the action.

[DAMIEN BLENKINSOPP]: I think some people would know the heart math device, the M wave, already, in a sense, because that’s very consumer focused. With that one you have a score – basically, you get to 11, 16, if you’re getting higher. So mapping that to what you’re saying is the higher the S-score just the higher the peak and the trough.

[RICHARD GEVIRTZ]: Yes, well, what they do is actually measure the frequencies and then they take the low frequency that’s in the range of their breathing divided by all the other frequencies, so it’s just a percentage of activity in the low frequency range, which correlates very highly to the peak-trough difference as well.
(0:32:25)[DAMIEN BLENKINSOPP]: I see. If we compare that to what you do, do you use a specific device or devices?

[RICHARD GEVIRTZ]: Yeah, so we use one of many different biofeedback devices. The advantage we have is we measure four channels usually or five: we measure heart rate beat-to-beat, based on EKG not a PPG. So you can either do it based on a pulse – the problem with a pulse is that you have to decide when the pulse starts and stops – versus an R-wave of an ECG, which is a very distinct event to start and stop the clock. If possible, it’s good to use an ECG, which we do. So we use beat-to-beat heart rate, we use respiration – we have strain gauges for respiration. We look at finger temperature and skin conductance – that’s sweatiness on the palms of your hands. All of those are useful indices for what’s happening.

If you can, the devices that just use the single channel heart rate – the emWave, MyCalmBeat, a number of other ones that are out now–are fine, they work, but it’s certainly not as good an information as if you’re using devices that have the four channels.

[DAMIEN BLENKINSOPP]: Right. So you’re using clinical machines?

[RICHARD GEVIRTZ]: Right. But some of those clinical devices are getting down into the 600-700 dollar range now. The ones we use range from about 3000 dollars to about 11,000 dollars.

[DAMIEN BLENKINSOPP]: Very clinical!

[RICHARD GEVIRTZ]: That’s not for consumers. But, there are a number of devices now that are coming out that are going to be with those four channels, that will be ECG, that will be in the 600-700 dollar range. But for everyday people, the emWave device that really works well is the Inner Balance, the one that runs off an iPhone. It’s a beautifully designed device and you can have it on an iPhone and it’s tremendous to manage.

[DAMIEN BLENKINSOPP]: Yeah, because it’s convenient.

[RICHARD GEVIRTZ]: It works well but you’ve got to be sitting in front of a PC, which is a big difference, but it’s cheap and it works well.

[DAMIEN BLENKINSOPP]: I’ve had both the emWave and the Inner Balance – is it Inner Balance or the Inner Sense?

[RICHARD GEVIRTZ]: The Inner Balance is a Hearth Math device; it’s the one that goes on the iPhone. The other Heart Math ones either run on a PC or they have a handheld stand alone.

[DAMIEN BLENKINSOPP]: I find it so much more convenient, I basically keep it in my jacket pocket. I’ll be on a train or anywhere where I’ve got a bit of free time and I’ll just pop it on.

[RICHARD GEVIRTZ]: Right, absolutely. There are also some free apps. What we do usually is we don’t advise people to buy those devices because we find their resonance frequency with our instruments and then we give them one of three or four different ways of practicing at that pace.

MyCalmBeat has a free app for pacing. There’s another one we like called Breathe2Relax – these are free apps – or there’s a musical pacer, that does cost some money but it’s very nice, called Breathe Sync. It has five different musical tracks at your particular pace, so we have a separate CD for each person. We let people choose the ones they want, whatever is the most convenient. It’s really important that it’s something they can practice with.

[DAMIEN BLENKINSOPP]: So this isn’t biofeedback – this is once you have done the biofeedback, you’re just giving them the timer?

[RICHARD GEVIRTZ]: Exactly. And some people just count. I can do it now – I’ve done it enough that I can get exactly to my resonance frequency pace just by counting.

[DAMIEN BLENKINSOPP]: And then you become like a yogi basically, you’ve just learned a lot quicker to do it.

[RICHARD GEVIRTZ]: Yeah, I learned to do it but I don’t do it hours a day so I’m not quite like a yogi. I do it ten minutes a day.

[DAMIEN BLENKINSOPP]: Is there any danger of overdoing this, like if you did too much of it?

[RICHARD GEVIRTZ]: Not that we know of. Some people do get anxious when they try to do it, but usually that only takes a bit of practice until they get out of that. As far as we know, there doesn’t seem to be any ill effects of this, but people have worried about it and perhaps overstimulating the parasympathetic system. But it doesn’t really do that – it just gets you better balance in the system.

[DAMIEN BLENKINSOPP]: Right. Because when you said it was like exercise, like hormesis in a way, right? I’m just wondering as we can overdo exercise.

[RICHARD GEVIRTZ]: Well, the yogis are the ones who overdo it. They breathe many hours a day and they don’t seem to be in bad shape from it. I don’t know. There’s tens of thousands of the emWave devices that have been used and I’m sure some people must overuse them, but I know of no reports of any really ill effects of it. There might be but I don’t know.

[DAMIEN BLENKINSOPP]: It sounds like a very simple approach you have, just covering a slightly low and a slightly high and then just finding the optimum by moving around by testing. One of those devices – the 600-700 dollar ones – are there any names of those that are coming out?

[RICHARD GEVIRTZ]: The two companies that make them, they’re not quite out yet, they’re coming soon, one is J&J Engineering, which has a new device coming out in that range that will do those four channels, but it’s not a portable device – it’s a PC device. The other company is called Thought Technology, that’s a big biofeedback company. They’ve got a little device that’s coming out that’s a fingertip PPG, just a pulse amplitude but it also measures temperature and skin conductance, and it bluetooths it to a tablet. Then it has an accelerometer so you can put it on your chest and it will also give you the breaths measurement. So those two are in that range of price and they’re coming out fairly soon. I think one is out but not with all the channels yet, so I’m not sure where they are exactly.

The other company that doesn’t have a cheaper one yet is called Nexus, a Dutch software package. Thought Technology and Nexus have very expensive systems, but they do many more things than that – they do all kinds of bells and whistles.

J&J is a bit cheaper, it doesn’t have as many bells and whistles, but they also have a 3000 dollar device that measures many channels as well, but it doesn’t have as many displays, so probably for the consumer, none of these are of interest.

I’d say right now, the consumer device that is far and away the best for portability, is Inner Balance from Heart Math. They’ve mastered some things that nobody else has mastered. That system seems to work extremely well. I have yet to find someone that doesn’t get an adequate pulse from their earlobe, whereas we used to get a lot of problems with pulses and not everybody could get a good pulse.

[DAMIEN BLENKINSOPP]: The only problem I’ve ever had with – I think it was the emWave – was I was living in Spain – very, very bright sunlight – and if I was in the sun, it wasn’t working. I had to be in some kind of shade. That’s the only thing I ever came up with.

[RICHARD GEVIRTZ]: That’s true for any of the PPG devices. I haven’t ever really tried it in a really bright sunlight. So those are the devices, but we’re not sure that people need to spend the money on those things if they can figure out what their pace is and then just practice on a regular basis. Twenty minutes a day is ideal but people will practice ten minutes a day.

[DAMIEN BLENKINSOPP]: What are other ways? If I don’t want to buy the device, do some physicians have these kits or some other kind of specialist, so I could basically go for a session? I don’t know how long it takes to do this, an hour or something, and they would figure out my perfect?

[RICHARD GEVIRTZ]: Yeah, there’s a guy near you in St. Albans at the Open University who does it. There are people around who do this. We do a lot of trainings with people all over the world. I was just in Rome training people from all over Europe, so there are a lot of people who do this. And probably even more people who aren’t very well trained but who have the emWave devices who probably give close to enough to be quite beneficial.

[DAMIEN BLENKINSOPP]: For you, would it be worthwhile one session even if you’ve been doing emWave? Would it be worthwhile doing one session? It depends how extreme we are about these things.

[RICHARD GEVIRTZ]: Well you know what, it’s very convincing when you see it on the screen. So even if you were able to get exactly the right pace yourself, seeing the actual physiology change is amazingly persuasive.

With our clinical clients, we take a baseline at normal breath rates and then show it to them again after they’re done with the training, and they get emotional. They’re seeing that their physiology really has changed; their baseline physiology has changed dramatically over the course of six or seven weeks of training. That’s one big advantage of it.

[DAMIEN BLENKINSOPP]: And, of course, you’re cross-referencing lots of different data, so you’re seeing the change across the whole body. Is there ever a case where you see the change in just the EKG and you don’t see it in the other areas? Are you cross-referencing that data or is it more just to make sure?

[RICHARD GEVIRTZ]: We do cross-reference it with fingertip temperature and skin conductance. Sometimes we don’t get those, that’s true. Sometimes they don’t click and that may just be they’re being nervous in the session or something while we’re measuring them. And some people get very small changes in heart rate variability, especially older people. It’s actually a very small quantitative change, but they seem to get the same clinical benefits.

As we get older, those peaks and valleys definitely go down. Even if you’re quite fit – I’m a bicyclist, I ride 110 miles a week. I’ve been monitoring mine for twenty years – it’s going down despite my best efforts.

[DAMIEN BLENKINSOPP]: Even with all the training. So you’re not able to get the same peaks anymore?

[RICHARD GEVIRTZ]: Right. It used to be 15 – the value of the peak for me, 16. Now it’s 11, it just little by little by little it goes down. But, the good news is that in terms of the clinical benefits, it doesn’t seem to matter, as long as you’re training at that right frequency, you seem to gain the clinical benefits of it. It doesn’t necessarily mean you’ll live forever, but it seems to help with a lot of parameters.

[DAMIEN BLENKINSOPP]: So that’s similar to RMSSD, which declines over age as well.

[RICHARD GEVIRTZ]: Exactly, and that’s exactly why it does. Any of those indices would be measuring somewhat the same thing.
(0:42:31)[DAMIEN BLENKINSOPP]: So you spoke about people doing this for a number of training sessions. For someone wanting to do this, how long would it take? What’s the typical protocol you’d put them through to learn when you take them on?

[RICHARD GEVIRTZ]: We need one session to make sure we have the right frequency. Then we send them home with the practice techniques, any of the ones they want. Then they come back the next week and we just make sure we’ve got everything right, because sometimes one week of practice will change it a half a beat and we want to just fine tune it. Some people are very sensitive to that, others are not. The rest of the time is depending on what they’re coming in for, so if they’re athletes, we now start to use some sports psychology to integrate it into sports psychology.

I work with a lot of rhythmic gymnasts who get very nervous before they go on – those are the ones with the hoops and the clubs, that funny sport; these are little girls basically and they get nervous.

[DAMIEN BLENKINSOPP]: You mean they’re quite young?

[RICHARD GEVIRTZ]: Yeah they’re 11 or 12. The coaches are Bulgarian usually.

[DAMIEN BLENKINSOPP]: They’re quite tough on them.

[RICHARD GEVIRTZ]: So we teach them the technique, they come back, make sure they have the technique–these kids are fantastic at it, they get giant peaks and valleys. They’re so fit and good at this stuff. Then we sort of integrate it into the cues in their routine where they tend to get nervous, pairing them together with some sort of sports psychology intervention, so that might take a few more sessions.

[DAMIEN BLENKINSOPP]: Are you getting them to trigger it at just the right moment where they would normally get a bit more anxious, but you trigger it just before something?

[RICHARD GEVIRTZ]: Exactly, and we have to work out how to do that. But for somebody who just wanted to do it for their own benefit, we probably could do it in two sessions, as long as they keep practicing, they’d do very, very well.

[DAMIEN BLENKINSOPP]: So they come back for a session of half an hour, an hour?

[RICHARD GEVIRTZ]: They come back for an hour. That’s what our standard session is, but we usually talk about other things during that hour. We also want to get a baseline again and so we try to distract them and just get them breathing normally. One of the problems is that if people don’t breathe normally, you can’t get an adequate baseline from them. So if they breathe slowly, it messes up their RMSSD data. It messes up all their data, so suddenly they don’t have any high frequency data. You have to make sure they’re breathing at their normal breathing pace when you’re getting baseline or follow-up data, and then when they do the slow breathing, then that changes everything.

[DAMIEN BLENKINSOPP]: Right, just to make sure you’re comparing to that – you’re getting a real control basically.


[DAMIEN BLENKINSOPP]: This is how they are in real life or this is how they are just before they’re going to compete, in the other example.


[DAMIEN BLENKINSOPP]: So would you give them a heart strap and monitor their athletic when they’re actually doing it?

[RICHARD GEVIRTZ]: We do do that, and that would be just for research purposes. We don’t do it for them. They’re not usually allowed to have that in a real competition anyway. It depends how they are, and it depends on what we’re doing.

Another application that’s not biofeedback but it’s an interesting HRV technique is for detecting over-training. FC Barcelona has got Leo Messi every morning doing five minutes of heart rate variability measurements, right in bed in the morning, and the training director monitor that. When they see dips in heart rate variability, they decide that it’s over-training and they ease up his training protocol. So if he has a couple of games in a week, they’ll monitor that and try to see, because over-training generally produces poor performance.


[RICHARD GEVIRTZ]: So that’s catching on like crazy. The sports psychologists are so competitive- if anybody gets anything, they all do it, just immediately.

[DAMIEN BLENKINSOPP]: They see it as a competitive advantage. I was thinking, you said they’re not allowed to wear those during competitions. Well I can understand why – if you’re getting biofeedback, it’s kind of like cheating. I don’t know if it’s cheating but you’ve got a competitive advantage.

[RICHARD GEVIRTZ]: Could be, yeah.
(0:46:33)[DAMIEN BLENKINSOPP]: What’s the performance benefit of being able to put yourself in this restful state? Say I’m just about to compete; is there a study showing there’s a performance benefit or another benefit, or is it just keeping their mental focus?

[RICHARD GEVIRTZ]: Yeah. It has to be for sports that are single action kind of sports, so golfing, gymnastics, baseball hitting, cricket batting, possibly penalty kicks in football; things like that. For aerobic sports, there’s no parasympathetic at all – they’re all in the aerobic range. It probably doesn’t make much difference for those, although it gives them a little bit of a psychological edge – it’s hard to detect the benefits there.

For baseball, one of my former students is in whole practice dealing with Major League Baseball players for hitting, because you’ve got a split second to make up your mind. The ball is coming at 95 miles an hour, and you have to be in exactly the right arousal level to be able to flow through that swing. It’s a way of getting an optimal flow state in things like that. Also in dancing and music, there’s a guy in London, John Gruzelier, who does it with dancing and music and combines it with brainwave feedback, and gets benefits for recitals and dance performances and things like that.

[DAMIEN BLENKINSOPP]: So it sounds like it’s eliminating nerves, is that the application?

[RICHARD GEVIRTZ]: Well, trying to get people into their optimal – to try to get them from over-aroused to the medium level. There’s a famous curve called Yerkes-Dodson Law, which is an inverted U-shape and the y-axis is performance, on the x-axis is arousal. Imagine an upside down U – people do the best in the middle, too high or too low isn’t good. We don’t want them to be relaxed, we want them to be psyched, but if they’re over-aroused then opposing muscles don’t work well, they began to get a certain choking mentality, they start thinking “What if I screw up?”, things like that.

[DAMIEN BLENKINSOPP]: I don’t know if you know about the science of flow and the books around flow. I can never pronounce the guy’s name, it’s very long and complicated – Csikszentmihalyi.

[RICHARD GEVIRTZ]: We think that we’re trying to go for the same thing. But it turns out, I was just at this conference in Rome and there were a lot of sports psychologists. One of the points they made, and it’s actually rare for athletes to be in the flow state during a performance, it’s definitely the ideal. These are people dealing with Olympic athletes, the most elite athletes in the world, and their experience is that maybe ten or fifteen percent of the time they actually get into their flow state. Now they’re saying the important part is if you don’t get into the flow state, don’t panic and go into the complete opposite quadrant where you’re really choking completely. But work on getting through the routine and the best arousal you can. That’s the first I’d actually heard that – I thought it was pretty interesting.

[DAMIEN BLENKINSOPP]: Right, so that’s more like limiting the downside, or focusing on not getting the troughs?

[RICHARD GEVIRTZ]: Exactly. There’s a guy working in London with FC Chelsea doing that, Tim Harkness. Chelsea has got a big room full of expensive biofeedback equipment, called “the Mind Room”. He works with all these multi-millionaire players. So it’s interesting to see.

Try to be self-observant, non-judgmentally observing your thoughts and breaths as you do it
[DAMIEN BLENKINSOPP]: One of the things I’ve done with Heart Math – you can tell me if this fits with exactly what you said – is I’ve tried many things to get my peak higher, of course, and get my highest score. I do think that what you’re doing with your mind seems… For me personally, I’ve had the biggest peaks and troughs over time by actually focusing on the wave in the device, so just watching the wave go up and down and then I breath at a specific point in that curve, which I found works for me.

[RICHARD GEVIRTZ]: Yeah, and I should have said that, so for some people, we don’t use the pacing at all – we do exactly what you do. We just show them their heart rate and respiration, we have the advantage of one more channel for them to look at, because you can see their breathing.

[DAMIEN BLENKINSOPP]: When you say one more channel, what would that be showing?

[RICHARD GEVIRTZ]: It’s showing a wave form of breathing, just a nice, smooth wave form of the breathing rate – so when you breathe in, it goes up; when you breathe out, it goes down.

[DAMIEN BLENKINSOPP]: In addition to the heart?

[RICHARD GEVIRTZ]: It could be smooth or jumpy and you want it to be smooth.


[RICHARD GEVIRTZ]: We would say exactly the same thing for a certain percentage of people: just make those two go up as high as they can, and down. Some people absolutely prefer that, they get their best results. I think partially because it takes away any performance anxiety, you’re just trying to match it as opposed to trying to breathe to a pacer. Some people really have a hard time breathing to a pacer, so we absolutely leave that as an opening – just do that, kind of thing.

We do try to promote a mindful mental set as well, so we try to say, “Try to be self-observant, non-judgmentally observing your thoughts and breaths as you do it.” I think there are some real benefits to doing that. I’m not sure it shows up exactly in the heart rate patterns, as we said earlier. I think that remains to be seen. If it does, it’s a pretty subtle difference.

[DAMIEN BLENKINSOPP]: If I started thinking about something stressful, like work, some problem I had at work, would that tend to put me off or would you think that would have a minimal impact compared to breathing, as long as your breath remained the same?

[RICHARD GEVIRTZ]: Right. It probably would be very hard to see as long as your breath stayed exactly in that same pattern. Oh, of course, it might interfere with your breath pattern too. Then you’d see it for sure; but if you maintained your breath pattern exactly the same, you’d probably have a very hard time seeing very much in there. Whatever it is – is subtle. If there is something to that, it’s probably quite subtle.
(0:52:35)[DAMIEN BLENKINSOPP]: What do you think about the connection between the brain and the breathing pattern in this case? By taking on this physiological breathing, do you think it will naturally affect the brain? I don’t know if there’s any research related to that, that it will put you in a different state of mind as well, as long as you maintain that.

[RICHARD GEVIRTZ]: We’re working on that now and we’re definitely finding pretty dramatic effects. Eighty percent of the vagal fibers are afferent – they go from the heart to the brain; only 20 percent of them are efferent – from the brain to the heart. This is something Heart Math has definitely pointed out and we agree with them on this completely, and it’s interesting. So the brain is listening to the heart more than the heart is listening to the brain, which seems counterintuitive. But they’re both part of a central autonomic system that integrates frontal lobe and some limbic system activities into the brain function. So really, it’s silly to treat them as separate systems – they’re an integrated system.

It appears that this technique has a powerful effect on the vagal afference going into the brain, so the brain states are quite dramatically affected. We recently published one study, and we’re just about to publish another, where we look at a brain wave called an evoke potential, it’s a very short – just for 800 milliseconds, and you do it for repeated stimuli. In this case, we take the filters off. Usually when they do EEG, you put a big filter on to get rid of that R-wave and the heart rate, because it messes up the EEG. But we take that off and let it mess it up, and you can see a very giant spike in the EEG for every heartbeat. Well there’s another wave that comes right after that – 250 milliseconds after. It appears to be the brain processing the information from the heart and it’s called a heart period evoked potential.

We measured that during positive emotions, negative emotions, baseline, slow breathing and resonance breathing. Resonance breathing had by far the biggest effect on it. Negative emotions did diminish that wave, so if your brain is busy thinking about the worst thing that ever happened to you, it doesn’t pay attention to your heartbeat anymore. During the slow breathing we got a dramatic improvement in this processing of the R-wave. It also correlates with people’s ability to be able to detect their heartbeat. There are some German studies that had people try to guess what their heart rates where. They were much better at it if they had that big wave at the 250 milliseconds.

So yes, I think the other powerful part of this is that we’re bombarding the parts of the brain that I think are beneficial to us with a very positive wave form – it goes up into the frontal cortex and the part of the brain we think that controls depression possibly – and this would be the basis for the claims of positive mental states coming from the heart rate itself. I think there’s a lot to that – we’re continuing to do more research on that. The results we got from both studies were very dramatic.

[DAMIEN BLENKINSOPP]: You mentioned a few use cases. What are the other most beneficial use cases that you have been working on over the years and you feel like the best applications for it are?

[RICHARD GEVIRTZ]: We mostly focus on autonomically mediated disorders, which are giant amounts of medical disorders. That would be things like functional gastrointestinal disorders like irritable bowel syndrome, reflux, functional abdominal pain, diarrhea, constipation. Those are massive familiar disorders and they’re greatly affected by the autonomic nervous system. There’s actually an institute right there in London, Wingate Institute (it might be a good thing for one of your podcasts actually), where they actually look at esophageal pain thresholds, with a nasal tube down the throat, and how they’re affected by autonomic function. They’re dramatically affected, and slow breathing changes the pain thresholds: it protects you from lowered pain thresholds. That probably is the low-hanging fruit in terms of applications.

We see about 15 kids a week with functional abdominal pain from our children’s hospital and we get tremendous results with those kids.

[DAMIEN BLENKINSOPP]: Is it therapeutic or is it just lowering the pain?

[RICHARD GEVIRTZ]: No, it’s therapeutic because the functional abdominal pain is actually caused by an imbalance in the autonomic nervous system. There’s no pathology that’s detected, these kids have been scoped, there’s nothing wrong they could find, but your gut needs a lot of parasympathetic input to function, and if you take that away… The kids that get this are all “internalizers,” they’re a little bit anxious kids – they’re great kids, they’re achievers, but they tend to be a little bit nervous, they worry about getting into a good university in third grade and things like that.

[DAMIEN BLENKINSOPP]: The famous insecurity overachievers.

[RICHARD GEVIRTZ]: Yeah, they’re lovely kids to work with, we love them, and they do very, very well. Adults don’t do as well but they still do well.
(0:57:55)[DAMIEN BLENKINSOPP]: You mentioned IBS as well. I think this is becoming a lot more common these days, a lot of people are getting these kinds of conditions and gut issues. Is it therapeutic also for those areas? Because a lot of people talk about probiotics, the microbiome, gut lining damage, gluten intolerance and all of these kinds of things related to these disorders, so I’m just wondering if you have had therapeutic benefits there.

[RICHARD GEVIRTZ]: Yeah, the relationship between the biome is complicated. I don’t think we know it, but it is definitely a parasympathetically connected system. We’re not quite sure whether we’re correcting it or whether it corrects us. The problem is the probiotics – there was a Cochrane Review on probiotics – apparently they are not near enough probiotics to have much effect, to really change the biome. But the biome definitely affects the brain, there’s no doubt about that, and probably through the autonomic nervous system. In fact we know it does through the vagal afferent system. So I think in the future, we will be pairing up with better techniques for improving the flora of the gut with these kinds of techniques that we use.

[DAMIEN BLENKINSOPP]: To kind of come at it from two different angles.

[RICHARD GEVIRTZ]: Both ways, I think that would be quite powerful.

(0:59:09)[DAMIEN BLENKINSOPP]: So you are seeing a permanent improvement in these cases, like IBS and stuff? But do they have to keep up the practice in order to maintain it?

[RICHARD GEVIRTZ]: We thought they did but then we did a follow-up and we asked them more in-depth questioning, and it turns out they just use the technique whenever they feel symptoms coming on – they don’t actually continue to practice very often. Some kids do, but a lot of them said, “Oh yeah, I keep on practicing,” and we asked them, “So what does that mean?” and they said, “Well, whenever my stomach gurgles, I do my slow.”

[DAMIEN BLENKINSOPP]: Okay, but that’s a good thing. That means that there is something that you’re fixing, basically, and so you don’t have to constantly – just maintain the practice in order to maintain it.

[RICHARD GEVIRTZ]: The kids with these disorders are at much greater risk for adult IBS – a lot of studies show that. We don’t know if we’re preventing that risk, but we think we are. We’ve had some five or six year follow-up with some kids and they seem to be doing just great at that point, so hopefully that will move on through their lives to be quite beneficial.
(1:00:01)[DAMIEN BLENKINSOPP]: Are there areas that you’ve looked at where it wasn’t effective? You mentioned depression – has it been effective in those kinds of neurological things?

[RICHARD GEVIRTZ]: I didn’t think it would be, but my students wanted to try it – I have a lot of doctoral students and we keep on consistently seeing beneficial effects on depression, probably through that vagal afference system. We are consistently seeing that and we’re doing more studies, and I think every study so far has shown a beneficial effect on depression. Sometimes they’re combined with psychotherapeutic techniques – in most of the studies they are. In one study they weren’t, they just did nothing but the biofeedback, and they got improvements, though there was no control group in that study. But the other studies, they are just adding it to cognitive behavioral therapy or one of the mindfulness-based therapies, and it seems to add a definite benefit to it.

In one study in China, they compared just slow breathing, without finding the right frequency, to finding the right frequency, and the frequency finding had better results than just slow breathing, even though that did help.

There are some indications that technique specifically might be beneficial. It probably is no more helpful than palliative techniques for chronic pathology like nerve pain, probably not very beneficial for people with Crohn’s or chronic IBD, inflammatory bowel disease. There is possibly an effect on the inflammatory system. There’s a guy called Kevin Tracey that has traced this cholinergic immunological system. There’s a lot of interest in that now, but we have not been able to show yet that it has any benefit on immunological function, but it may be.

There’s research coming out now that is indicating it might have an effect on one part of the immunological system. There’s a vagal part of that system that may help, and if it does work, it would probably be that it would be helping the system from going bonkers. Sometimes people’s immunological system turns on and doesn’t turn off again – autoimmune diseases – and nobody knows quite why that is, but it looks like strengthening this vagal system might prevent that. That would be that it might help to reset it; there are some claims of that. I would say the evidence is just beginning now.

Other disorders, it doesn’t seem to help for atrial fibrillation for some reason, that’s kind of a nerve induction of the heart itself. Pacemakers aren’t involved. At my age, all my friends are getting atrial fibrillation. I’ve tried it on all of them and it doesn’t seem to help very much. Then there are probably a number of physical disorders that it doesn’t really help. If it’s an autonomically-mediated disorder it seems to be quite effective.
(1:02:52)[DAMIEN BLENKINSOPP]: I guess what we haven’t spoken about is people’s emotional happiness and things like that. Are there any evidence that it improves satisfaction or happiness or stops angry outbursts?

[RICHARD GEVIRTZ]: Yeah, we have a couple of studies that show it helping with urge control. The pathway back up into the brain seems to go through the places that have inhibitory neurological control of emotion, so we have some reason to believe that if you can improve those inhibitory circuits, that would help a lot with anxiety, help a lot with urge.

We’re doing one now with smoking, people who are in smoking cessation programs, to try and help them with their cravings. There’s a food craving study that showed benefits for food craving and we’re doing another one of those right now actually. So there’s some reason to believe it might help with some of those kind of impulsive urge kinds of things.

I’ve used it with clients with anger control and they’ve reported the results, but there are no studies that I’ve seen, so it may be helpful for anger control. But we don’t just do it alone; we always combine it with a lot of other techniques. It’s going to be hard to show that by itself it’s a beneficial technique.

Heart Math has all kinds of studies on stress, self-reported stress, and self-reported life satisfaction that always show benefits but it’s hard to know how much of that is placebo and how much of that is the actual technique. I think it helps people, but the studies are hard to do and it’s self-reported – you have to put in a sham control of some sort to make them think they’re getting something that they’re not – but it’s hard to do those.
(1:04:30)[DAMIEN BLENKINSOPP]: Right, that is hard. Have you seen anything with cortisol levels or something like that, hormonal?

[RICHARD GEVIRTZ]: There’s a little bit of data in burned out cortisol patients with long periods of rehab – they do better. But there again, we don’t just do that, we do it with integrated exercise, with activity management, with sleep management. Those are the things that all go together in these syndromes and I would never just do the biofeedback. But biofeedback is the part they like the best.

[DAMIEN BLENKINSOPP]: There are benefits to that if they’re actually interested in coming into the physician’s office.

[RICHARD GEVIRTZ]: Exactly. We say it’s the “Trojan horse technique” – it gets people in, they don’t resist it. That’s true for a lot of disorders. With veterans we get them in by saying we’re doing biofeedback before we do any psychotherapy with them.

(1:05:16)[DAMIEN BLENKINSOPP]: The part you brought up about resisting impulses, so impulse shopping; we can think about lots of things we do on impulse. Personally, for performance at work and with my businesses and everything, I find that extremely important. Basically, in the morning, if I do some meditation, perhaps do some Heart Math, I do feel more in control and I’m less likely to work on something that is a waste of time for a couple of hours, rather than exactly the right thing that was going to bring the best results. So I find it from a performance perspective to be very, very important.

There’s a big trend in meditation. I also have a device which I can use – I don’t know if you’ve seen this – the Muse. It’s an EEG, you place it on your head and it tells you how calm you are in terms of alpha waves and so on. I’ve used both and I’m not sure, sometimes I’m left wondering “Which one shall I use today?” or “Which one shall I do this morning?”. I’m not exactly sure which one would be the most beneficial, so I’m just wondering if you have any perspective on it, or if it’s worth doing both, or one on one day and one the other day?

[RICHARD GEVIRTZ]: If you hook then both up, I think you would see that your optimal alpha state will come very quickly when you’re in resonance frequency, which to me is much easier to do. But, and I’m interested in your feedback, do you think the feedback on the EEG is as beneficial to you as on the emWave?

[DAMIEN BLENKINSOPP]: I feel like it’s different, honestly. I’m actually using Inner Balance on that now. I used to use the emWave before. With that one, I tested meditating, so I’m doing mindfulness meditation, and I didn’t get good scores in the Heart Math device. However, I definitely used breathing when I’m using the alpha wave thing and it definitely does help. So, it’s interesting, and I’ve heard that from other people using this – if they use their standard meditation, they don’t tend to do well on the Heart Math.

[RICHARD GEVIRTZ]: No absolutely. It’s because you’re not breathing in the low ranges with that. What is your standard meditation, is it a mantra-based one?

[DAMIEN BLENKINSOPP]: I’ve tried different ones. I’ve tried the mantra, and just the breathing mindfulness. The worst I would say, mantra is worse.

[RICHARD GEVIRTZ]: We get nothing from mantra people, even with years and years of mantra work – it doesn’t tend to train their breath. We did transcendental meditation with 30 year meditators and we were looking at brain scans at the same time. They had dramatic effects on their brain scans. Their mantras really affect their [unclear 1:07:45] a lot. But, we saw no effect on their breathing whatsoever, which is sort of good for the scanner because if you change your breath, it changes the BOLD response in the FMRI, which is an artifact. So then suddenly you don’t know what the heck you’re measuring. But in breath meditators, it just seems to vary a lot, so some of them do breath in the resonance range so they absolutely get both going together.

The Muse will definitely teach you how to get into an alpha state, independent of breath. Those are two separate things, so it’s interesting that you say that. To me though, if I hook myself up to an EEG, it’s so much easier for me to get into alpha by just breathing slowly than it is by paying attention to the EEG feedback that I don’t bother with.

[DAMIEN BLENKINSOPP]: Right, because you’ve potentially learnt. I’d love to run them both, but I need two phones because they both interface with the iPhone and you can only run one app at a time, unfortunately. So I’ll have to get an additional phone. It will be interesting to see how that works out.
(1:08:47) The last thing is–we did touch on it just before the interview – there’s a lot of people talking about gratitude types of meditation and empathy and that kind of thing, and that having an impact. How do you feel that connects or it doesn’t connect?

[RICHARD GEVIRTZ]: I think it only mildly connects, but I think it’s an independent, important thing to do. In our clinical training, we start with the biofeedback and we end up with mindfulness-based techniques, that’s pretty much all we do. We don’t do cognitive behavioral therapy at all anymore – the kind we like is called “acceptance and commitment therapy,” ACT. It’s another one of many, and it has a strong compassionate meditation, strong mindfulness component. I think most of those have the same kind of strong component.

I think it’s important for your brain functioning to learn those things. It doesn’t seem to have much impact on the heart rate variability, as we were saying before. I don’t see a ton of impact on heart rate variability and that’s mainly because breath is such a dominant factor in what we’re saying on that screen. As we get more sophisticated, we might be able to tease out some non-linear components or something once your brain is in a mindful state – it should show up somewhere.

The thing right now is like you walk into a room full of people talking loudly and trying to hear someone across the room whisper. It’s hard to pick it out because it’s a small component in the overall picture of heart rate. But, certainly there’s a lot of evidence now from brain scanning type techniques and EEG techniques that people do benefit from repeating it. It’s a skill, it’s very important to know it’s a skill, and the more you practice those mindfulness, compassion and forgiveness type skills. The evidence is strong that for instance forgiveness produces beneficial health outcomes, no doubt about it, and so does compassion. Those are things that we know are beneficial in some ways but probably in somewhat independent channels.
(1:10:48)[DAMIEN BLENKINSOPP]: Great. What’s coming next? You mentioned a few things, so in the future, are there any things you are looking forward to in this area or directions you’re moving in to? You mentioned a couple of things over the period.

[RICHARD GEVIRTZ]: I have a slew of students so we’re all doing this kind of research, so we generally focus on maybe three things. One is just outcome data from heart rate variability biofeedback. We keep on doing studies and trying to see what it works for, and we’ve got a bunch on those going so we’re always looking at how does it work compared to other techniques and compared to other controls, and we tend to get very positive results out of that. I just published a literature review on that and we have quite a number of applications where it looks like it works. We don’t have much big funding so we have to do little small studies – big pharma is not too interested in this technique, as you might guess, as “skills and not pills” is our motto.

The second one is mechanisms, so we make reference to how does it work? What are the other mechanisms here? There’s a whole bunch of new stuff on that. Vaschillo, that Russian guy, is looking at rhythms in the very low frequency range and seeing what happens to the blood pressure systems when you breathe at like three per minute, and there’s some really interesting data coming out on that. We’re trying to understand both psychological and physiological mechanisms of why this works, how does it work – we’re going to do many more studies looking at how the brain is affected.

The third one is, I’ve sort of been dragged kicking and screaming into this by my students, but looking at yoga and trying to standardize yoga and see what are the mechanisms by which yoga works. The other mechanism that I think is important but we have not been able to pin down, is the postures. We know the pranayama component of yoga is very important–that’s what we study, and it’s real easy to study that–but when we look at the postures, the body was evolved for movement so there are massive afferent pathways from muscles back to the brain and we’re quite interested in what are those pathways and how does the movement complement the breathing. The thousands of years of looking at movement-breathing complementarity – there’s probably something to it, but it’s very hard to study that and it’s very hard to figure out how to study those afferent muscle pathways. There’s not a good way to study it non-invasively – so that’s an issue.

We’re doing yoga studies for IBS right now, seeing how much heart rate variability changes. These are students who are very proficient in yoga, they were instructors and they beat me up until I let them [unclear 1:13:27] on yoga. There are assorted other topics that come up.

There are a lot of parametric things we don’t know, like [check 01:13:36] Hubbard inhalation-exhalation ratio: is it important to breathe 40% in, 60% out? That’s what everyone thinks but now there’s one study that shows that no that’s not very important, 50/50 is okay. Another study showed that 40/60 is better, so we want to look at that. We want to look at lying down versus sitting up. So these are little studies we do, parametric studies, so the students can get a scientific poster out of it and we present it at a meeting, and if it comes out, then we try to publish it. These are things that really nobody is studying and we really need to know those things.

Tight-fitting clothing – it looks like women who wear very tight-fitting waists don’t breath diaphragmatically at all, and it looks like it has a detrimental effect on them.

[DAMIEN BLENKINSOPP]: These are useful things. You find the answers to these, you can improve a whole bunch of lives.


(1:14:27)[DAMIEN BLENKINSOPP]: Mass market kinds of lives. I came across you first in a presentation video. I’m just wondering, what are the best ways to learn more about you and your work? Are there presentations you have got up online? Are you on Twitter? Do you have a website? Where’s the best place to connect with you?

[RICHARD GEVIRTZ]: We have some YouTubes out there. I avoid Twitter like the plague. One of my students, Mark Stern, did a very nice YouTube explaining heart rate variability biofeedback – it’s fairly recent. If you just Google “Mark Stern HRV BSC” (Biofeedback Society of California), it’s the first one that pops up as it’s got a long address. He goes through and explains how the biofeedback works and some of the stuff we’ve been talking about.
HeartMath has a lot of stuff too, so a lot of their stuff is really good.
(1:14:27)[DAMIEN BLENKINSOPP]: Great, so I’ll put all of that in the show notes.

Is there anyone besides yourself – you’ve mentioned a few people already, but is there anyone else you would recommend that people look up to learn more as well?

[RICHARD GEVIRTZ]: There are websites – the one you saw probably was from Thought Technology, because they keep on doing things with me and putting them up there. My website – I have a hard time keeping it recent, but there’s a lot of stuff from the Association for Applied Psychophysiology and Biofeedback, AAPB. We’re just coming out with another magazine, a whole magazine and all the articles on HRV, and they tend to be lower level, not quite as scientific. And we publish things in regular journals all the time.

There’s a woman named Inna Khazan in Boston who published a book of combining biofeedback with mindfulness techniques. That’s a really nice book. I hope to review it for the publisher, and she did a very nice job on that book. She’s using our techniques pretty much, she’s taken our workshops, but she’s quite an accomplished mindfulness-based therapist and she put that altogether in a book that she has published.

[DAMIEN BLENKINSOPP]: That sounds great. Thank you for that. So just a little bit about you and how you approach data in your life. I’m just wondering if there are any biomarkers or anything you track in your life – could be HRV, could be other things – and use it to make decisions or just to keep track of where you are at personally?

[RICHARD GEVIRTZ]: Well, I do check HRV but it’s kind of discouraging since it goes down as I get older. I do it sometimes because it’s easy just to hook myself up. I do the breathing on my own, I don’t need the devices anymore to do it so I do the breathing myself. I have a heart rate monitor for my bicycling, which is a little bit useful actually. By now I know exactly which hills produce which heart rates, so I actually don’t bother with it a lot of times. I know exactly where my heart rate is from my bicycling.

I monitor my blood pressure regularly, just because it’s a risk with aging. But that’s all I do; I don’t monitor any other biomarkers. I suppose I could do over-training, but I don’t think I’m in danger of over-training. Possibly I do; sometimes on Saturday I ride with a group that pushes me too far. I probably would have lower heart rate variability on Sunday morning, but I know that because I feel crappy.

[DAMIEN BLENKINSOPP]: We’ve talked a lot about HRV on this show, as you’ve probably seen, and there are some situations where I find I’ll have a low HRV in the morning and I feel okay and it will hit me probably at lunch or a little bit later. So at four in the morning I was okay, and my HRV says “You’re not okay.” There are a few times like that it’s been a – how do you say – a forerunning signal for me.

[RICHARD GEVIRTZ]: Yeah because what it’s picking up is vagal withdrawal. One of the implications of this is what makes people have ill effects, unless they’re in war or something, is not sympathetic over activation as much as vagal withdrawal. So the minute you get up and you have a big busy day of stressful things in front of you, you don’t get a big surge of sympathetic activity usually, and maybe during a presentation you might, but what happens is your brake goes off, so your vagal brake is off. If it’s off for about 90 minutes, your body doesn’t like that so it will show up in whatever the most vulnerable body system you have is.

For the gut problems, it shows up in gut problems for those people, but if you have a trigger point, it will show up in trigger point pain. Or if you have performance issues, it will show up with not feeling sharp in your performance. So I think that’s what you’re picking up. Probably it would be a good idea if you wake up with it to do some biofeedback, try to get yourself back on track. Or break up the morning sometime with ten minutes of slow breathing, maybe combined with some alpha, and just to do that as a middle of the day break is really powerful. That will put you back in balance and then you’ve got another 90 minutes of messing it up again before it will start to affect you again. 90 minutes is a total guess but that’s what we say.

[DAMIEN BLENKINSOPP]: That’s great, thanks. There are some very useful tactics there to keep me performing.

Just the last question here, what would be your number one recommendation for people if they want to use data in some way in their life to improve their health, what would be the one way you would recommend doing that?

[RICHARD GEVIRTZ]: Well, the Inner Balance actually has a – it’s tricky but you can get heart rate variability data out of it. If you wanted to monitor your heart rate variability on a daily basis, this would probably be interesting to some people; it’s a lot of trouble. There’s a free software program that you can load it into called Kubios HRV. It’s a Finnish program – it’s free, you can download it on your PC. Then you can actually export Heart Math data or any of those device’s data to that–for resting level data – and it will give you, actually a very respectable heart rate variability profile with all the measures we talked about and many more.

If somebody was really into it, they could do that on a regular basis. It’s a little tricky how to get the Inner Balance to output that data. You have to write to Rollin McCraty and he’ll give you something to load that’s not meant for that, but you can do it. Or if it’s one of the other devices, it will do it easily. That might be something that would be worth keeping track of, although I think really, in the long run, just how you feel, you know what’s going on and if you know what’s going on and you just intervene properly, you’d probably be just as well off.

[DAMIEN BLENKINSOPP]: Yeah, self-awareness. Great. Well thank you so much for your time. I’ve found it really interesting. There were some things I wasn’t expecting–the yogis, a great story as background to how you got into this and the 1000 year old knowledge was an input into all of this. Thank you so much for your time, it’s been a lot of fun.

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A look at a collection of high impact endurance tools and tactics – and the top biomarkers to watch for optimization. Vetted by an endurance athlete with years of experiments and competitions behind him.

Today’s episode is about endurance training and using high-impact tools to get the most out of it. We look at self-tracking in diet and exercise when aiming to optimize your body to perform at peak capacity.

We discuss factors playing a role in improving endurance through a healthy progression. What self-quantifying strategies are useful for tracking overall performance and health?

This episode features actionable takeaways on dealing with a variety of obstacles commonly experienced by endurance athletes.

How to make use of ketogenic dieting in maximizing fat-burning efficiency during physically demanding exercise? Which biomarkers are important for tracking individual organ-systems functionality in the body? How to maintain a healthy hormonal status?

Overall, we look to beneficial and practical tactics for athletes wishing to upgrade their performance and discuss common pitfalls to avoid in cultivating endurance.

On this full-on ketosis diet… the endurance payoff was huge. The amount of focus that I had for long periods of time. My ability to just hop on a bike and ride for hours with no fuel at all, with just water. It was pretty profound, because you produce all these ketones as a bi-product of fatty acid oxidation, and they’re used as the preferred fuel… while you’re out exercising. And that’s a huge boon to an endurance athlete.
– Ben Greenfield

Today’s guest is Ben Greenfield who is a professional competitor in endurance-demanding events, including triathlon and Ironman races. Ben has 11 years experience coaching athletes and fitness professionals.

Throughout his athletic career, he has researched physiology of upgrading endurance using a quantified approach. He has performed numerous self-experiments targeted towards understanding his performance parameters, and towards optimizing his diet and exercise.

Ben is the author of a New York Time’s best-selling book titled “Beyond Training: Mastering Endurance, Health, and Life”, which was published in 2014. His top-ranked iTunes podcast is called BenGreenFieldFitness.

The episode highlights, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

What You’ll Learn

  • Ben uses his biohacking experience to coach people on living healthy and attempting on-the-edge extreme exercise (4:46).
  • Ben’s interests in endurance training and research developed over time. No big eureka moments, just meaningful experiences (7:12).
  • Important biomarkers in endurance training specifically, and practical reasons for these picks in exercise self-tracking (11:24)
  • Why regulation of sex-hormones and cortisol (the stress hormone) are important to track in endurance training (15:50).
  • Why standard reference ranges for free testosterone are often not applicable to endurance athletes (16:48).
  • Liver enzymes, kidney parameters, Vitamin D, and digestive track inspections are also key biomarkers for healthy endurance training (18:20).
  • The digestive track plays an upstream role in multiple athlete pains and discomforts (21:18).
  • How to fight thyroid system dysfunction in endurance training (24:17).
  • The key lessons Ben learned from his 12 months ketosis dieting experiment (26:10).
  • The biomarkers for detecting adrenal fatigue symptoms (27:22).
  • Biomarkers and tests for autonomic nervous system functionality and distinguishing adrenal fatigue from thyroid system dysfunction (28:03).
  • Incorporating Heart Rate Variability (HRV) tracking in endurance training (31:39).
  • HRV is Ben’s ultimate marker for optimizing endurance training and quantifying overall health (33:23).
  • Success in endurance training requires optimization between high-volume achievements and short-duration precisely aimed tasks (34:29).
  • Dealing with negative effects of endurance exercise and ketogenic dieting (39:01).
  • Maximizing ketogenic dieting benefits and potentially useful supplements (44:34).
  • Breath ketones are an easy way to test for purposeful ketosis (46:20).
  • Tracking important biomarkers and avoiding excessive ketosis (47:20).
  • Why oxaloacetate can be used as a supplement with ketogenic dieting (48:25).
  • Why cold thermogenesis works for athletes’ bodies, for recovery and for overall performance (50:27).
  • The portal outlining Ben’s work and relevant people recommended by Ben (53:17).
  • Ben’s most-important advice on living healthy is being grateful several times per day (54:48).

Thank Ben Greenfield on Twitter for this interview.
Click Here to let him know you enjoyed the show!

Ben Greenfield, Greenfield Fitness Systems

Tools & Tactics


  • Cold Thermogenesis: Can be achieved through a variety of cold exposure methods such as cold showers or dipping into cold water streams . In cold thermogenesis hormesis is used to promote positive adaptations in the body as we saw in episode 8. Amongst other improvements it can help to burn fat more efficiently and improve blood vessel functionality in part by promoting development of your Brown Adipose Tissue (BAT). BAT is a type of fat which is active tissue and able to generate heat.


  • Heart Math Gratitude exercises: The Institute of Heart Math promotes using specific gratitude exercises to optimize the HeartMath Heart Rate Variability (HRV) score. We’ve discussed the HeartMath form of HRV previously in episode 6. This exercise can be done with one of either of their two HRV feedback devices: Inner Balance for iOS or emwave2.


  • Thyro-Gold: Thyroid glandular extract produced by the New Zealand company Natural Thyroid Solutions. This supplement is used as a biohack to correct thyroid-system dysfunction, sometimes caused by ketogenic dieting – especially with very low carbohydrate intake and endurance exercise.
  • AndroGel: Although the use of testosterone hormone-containing products is illegal in professionally-sanctioned sports events, this supplement is sometimes used because free-testosterone levels often drop in a ketosis state.
  • Ketosports KetoForce: KetoForce contains the endogenous ketone body beta-hydroxybutyrate (BHB) in sodium and potassium salt form. The compound BHB can be used as an energy source by the brain when blood glucose is low. Ingesting KetoForce raises the levels of blood ketones for 2.5-3.0 hours after ingestion. (Note: A similar product from same company is Ketosports KetoCaNa).
  • benaGene: This supplement, oxaloacetate, was previously covered in depth in episode 30 in an interview with its creator Alan Cash.
    Greenfield uses this specifically to increase the rate at which his liver synthesizes new glucose molecules, during a low-carbohydrate ketogenic diet including exercise. The goal is to take advantage of its ‘glycogen sparing’ effect, since glycogen is less available in ketogenic diets, and thus get more intensity out of workouts.

Diet & Nutrition

  • Ketogenic Diet: A ketogenic diet is low in carbohydrates intake and high in fat intake. As such, it induces a state of ketosis in the body – the condition in which the body burns fats and uses ketones instead of glucose for fuel. Previously, we discussed measuring ketones and ketogenic dieting in Episode 7 with Jimmy Moore.
    To provide scientific support in favor of ketogenic dieting for endurance, Ben suggests the research of a University of Connecticut team investigating athletic training and human performance. For more information, see this recent scientific review authored by them on using fat as fuel for endurance exercise.
  • Cyclic-Ketogenic Diet: In some people, full ketogenic diets can lead to hormonal or organ dysfunction (e.g. thyroid). The cyclic-ketogenic diet is the solution often used to avoid these downsides. This is a low-carbohydrate diet with intermittent periods of high or moderate carbohydrate consumption (e.g. a refeed with carbohydrates every weekend). It is used as a way to maximize fat loss while maintaining the ability to perform intense exercise during a ketosis state.
  • Based on his 12 month ketosis self-experiment, Ben has concluded that eating anti-inflammatory food, as well as increasing intake of food containing medium-chain triglycerides (MTCs) and resistant starches, are all beneficial in reducing the potential negative side effects of ketogenic dieting.


  • Polarized Training: Polarized Training is scientific terminology for the concept of easy-hard training. Researchers from the University of Stirling in Scotland have concluded that using an approach which excludes medium-intensity training is more beneficial for building endurance compared to an approach that includes medium-intensity training. The polarized training model (80% low-intensity; 0% medium-intensity; 20% high-intensity training) produces more positive results in endurance athletes, compared to the competitor threshold model (57% low-intensity; 43% medium-intensity; 0% high-intensity training).
  • Murph Workout: “Murph” is a CrossFit workout named after Navy Lieutenant Michael Murphy, who was killed in Afghanistan June 28th, 2005. He was awarded the Congressional Medal of Honor after his death. It first appeared on the CrossFit site 18 August 2005. This workout consists of (in order): 1 mile run, 100 pull-ups, 200 push-ups, 300 squats, and a 1 mile run at the end.



  • Heart Rate Variability (HRV): HRV is the measure of the change in the heart’s rhythm over time based on changes between sympathetic and parasympathetic activation. HRV was previously covered in the context of optimizing training workouts using HRV in Episode 1 with Andrew Flatt and using HRV as a biomarker for longevity in Episode 20 with Dr. Joon Yun.
  • Triglyceride to High Density Lipoprotein (HDL) ratio: Researchers have shown that using the triglyceride to HDL ratio is a better predictor of coronary disease risk factors, compared to tracking total cholesterol (which includes HDL and other lipoprotiens). A ratio of 2 : 1 or less is considered optimal.
  • High-Sensitivity C-reactive protein (hs-CRP): CRP is a protein that increases in the blood with inflammation and is used as a marker for cardiovascular health (high levels over 1 mg/l are indicative of higher cardiovascular risk). Both diet choices and overtraining can lead to high levels of hs-CRP (over 1).
  • Ketones: Ketone concentrations can be tested in blood, breath and urine samples to determine if you are in ketosis (burning ketones for fuel) and to what extent. We covered these markers extensively in episode 7 – how to measure ketones.
  • Creatinine and Blood Urea Nitrogen: These two biomarkers are often elevated above normal levels in endurance athletes, without being indicative of a health risk. In endurance training, creatinine levels lower than about 1.1 mg/dl do not pose a health risk. It is also relatively normal to have BUN levels over 20mg/dL.
  • Liver Function Tests: When excessive exercise is present, the blood levels of liver enzymes Alanine Transaminase (ALT), Aspartate Transaminase (AST), and Alkaline Phosphatase (ALP) are elevated above normal.
  • The 25-hydroxy Vitamin D Blood Test: The most accurate way to measure how much vitamin D is bioavailable to be used by your body is the 25-hydroxy vitamin D blood test. Optimum vitamin D levels range between 50-70 ng/ml.
  • Salivary cortisol to Dehydroepiandrosterone (DHEA) ratio: An increase in DHEA levels is highly suggestive of adrenal dysfunction because DHEA is produced exclusively by the adrenal glands. Excessive exercise stresses the body to produce very high levels of cortisol, which causes a depletion of endogenous DHEA. This results in an elevated cortisol to DHEA ratio. Testing for this ratio several times per day provides a more complete image of adrenal function, compared to a snapshot provided by simple monitoring of blood cortisol levels. A normal cortisol : DHEA ratio is approximately 5:1 to 6:1.
  • Thyroid Functional Test Panel: A TFT panel typically includes thyroid hormones such as Thyroid Stimulating Hormone as well as the thyroid hormones triiodothyronine (T3) and thyroxine (T4). Excessive exercise can stress the body to produce high-levels of cortisol (the stress hormone) which inhibits the conversion of thyroid hormone from inactive (T4) to biologically active (T3). This can result in lower levels of active thyroid hormone despite normal or up-regulated levels of TSH. Thus, testing for (active) T3 hormone concentrations is more relevant for endurance athletes self-tracking. Optimal reference ranges for TSH are 0.4 – 2.5 milliunits per liter (mU/L). Optimal reference ranges for free (bioavailable) T3 range between 350 – 780 pg/dL.
  • Sex Hormone Binding Globulin (SHBG) and free testosterone: The standard reference ranges for SHBG are 0.2-1.6 mg/dL for non-pregnant adult females and 0.1-0.6 mg/dL for adult males. Changes in SHBG levels affect the amount of free hormone that is available to be used by tissues, including the levels of free testosterone. In case SHBG levels are in abnormal ranges, then free (bioavailable) testosterone should be tested (reference ranges 1.0-8.5 pg/mL for females and 50.2-210.3 pg/mL for males).
  • Tests for detecting adrenal fatigue and thyroid system insufficiency

  • Iris Contraction Test: This test consists of you looking at the pupil of your eye in a mirror while shining a bright light at your eye. The light should cause the pupil (center black spot of your eye) to contract or become more narrow. The contraction should be sustained for longer than 20 seconds before the pupil starts to flicker or dilate. Otherwise, if the pupil starts to flicker immediately upon shining light, this is a good indication that you have adrenal fatigue – mainly because your adrenal gland is functioning properly in managing blood pressure.
  • Dizziness Test: If you lay down or you sit down and you stand up quickly and you get dizzy, then this is a sign of blood pressure mismanagement. Importantly, problems with blood pressure often accompany adrenal fatigue because one of the main functions of the kidneys is to regulate blood pressure via production of hormones in the adrenal gland.
  • Broda Barnes, MD Temperature Test: This test was developed by Dr. Broda Otto Barnes, who was best known for developing novel perspectives on hypothyroidism – a type of thyroid system disease. In essence, you do oral and armpit measurements every morning in bed upon waking up and keep a graph of the results. If your temperature is consistently low, then this is an indication that your thyroid system is dysfunctional even in the absence of a blood thyroid test.

Lab Tests, Devices and Apps

Other People, Books & Resources


  • Dr. Terry Wahls: Dr. Terry Wahls is a a clinical professor of medicine at the University of Iowa. Previously, Dr. Wahls was kind to participate in the third episode of our show, where we focused on linking mitochondrial health to autoimmune and chronic disease.
  • Alan Cash: Alan Cash is the CEO of Terra Biological. Previously, he has been a guest on our podcast in Episode 30, where we discussed the potential for using oxaloacetate as an anti-aging supplement.
  • Joe Friel: Joe Friel holds a masters degree in exercise science and is a USA Triathlon and USA Cycling certified elite-level coach. For Joe’s blog click here. For his Twitter click here.
  • Sami Inkinen: Sami Inkinen is a balanced person. He is a successful businessman and a top-age Ironman competitor. For his Twitter click here.
  • Dr. Peter Attia: Dr. Peter Attia is a scientist who is knowledgeable in healthy endurance exercise and self-quantification. For Dr. Attia’s Eating Academy Blog click here. For his Twitter click here.



Full Interview Transcript

Click Here to Read Transcript
[04:46] [Damien Blenkinsopp]: Ben, welcome to the podcast.

[Ben Greenfield]: Hey, thanks for having me on man. And I’ve got to ask you, is it Damien, or Damion? Or Dami-something else?

[Damien Blenkinsopp]: Or Damian? It depends where you come from, I guess.

[Ben Greenfield]: Okay. Just checking. I don’t want to stick my foot in my mouth.

[Damien Blenkinsopp]: Yeah. You can call me Dam. I tell people to call me Dam, just to avoid all those questions.

[Ben Greenfield]: There we go. I want to sound like I’m cursing the entire episode.

[Damien Blenkinsopp]: Yeah. But it even works in Asia, tried and tested.

[Ben Greenfield]: Nice.

[Damien Blenkinsopp]: I mean you’ve got a three letter name. That works well.

[Ben Greenfield]: Yeah, totally. Ben.

(05:12) [Damien Blenkinsopp]: So, Ben, you’re into triathletes, Ironman, and basically the way I look at you is you go around searching for tactics and tools to give you an edge in these areas that you’re interested in. Is that a fair kind of back story to who you are and what you’re doing?

[Ben Greenfield]: Yeah, I do a lot of that I guess n=1 guinea-piging myself. Going out and doing crazy things like training with the Navy SEALS or doing these Spartan Races or Ironman triathlons, things like that.

But then I also think I learn just as much via a lot of the coaching and consulting that I do, just because people typically come to me for one of two reasons.

They either want to do some crazy feat that’s completely unnatural for the human body to do, like they want to go run 100 miles in the wilderness or something like that, and figure out how to do it without destroying themselves. So my job is to figure out how to do that from a nutrition and a physiology and an exercise standpoint.

Or they come to me because they basically want to live as long as freaking humanly possible, and want me to manage how do you sleep when you want to do something like that, how do you exercise, what do you measure, what do you pay attention to in your blood and your gut. And so there’s that kind of biohackiness that I get into.

And I’ve got to admit, for me personally it’s a little bit of both, really. I certainly do want to live as long as possible. I also want to do as many crazy events as I can during the process, see as much of the world as I can at the fastest pace possible. And so for myself, personally, I’m doing a little bit of both.

But sometimes people come to me and want to do something that I know nothing about, so I’ve got to go and learn it. So part of it is that, too. That, or if it’s not coaching someone it’s writing about that. Because I’ve done a lot of writing recently. This morning [I] published a big article on my website about how to use marijuana to get performance enhancing gains.

And I never really would have delved into that if I hadn’t been asked by so many people, especially here in the US with the growing legality. It’s like, can I use this while I’m exercising? That type of thing. So it’s a little bit of everything.

[07:12] [Damien Blenkinsopp]:Yeah, great. So [what was] the event that started the whole Ben Greenfield fitness podcast, and the blog and everything? How’d you get involved in that? Because you’re obviously very passionate about it.

[Ben Greenfield]: Yeah. Well there’s, I mean I get that question a lot, and frankly – nothing against you – but it annoys me, because I hate when people go, “When did you decide to do this? When did you decide to do that?” I never make decisions. I don’t have a 10 year business plan. I don’t have some ‘Come to Jesus’ moment where I said, “Oh hey, I want to learn how to exercise.”

It’s just that I live my life. I do things that I’m passionate about, or that other people who I’m helping are passionate about and tend to fall into whatever I might fall into based on that. I’m getting into hunting right now – well specifically bow hunting and hunting competitions – before that obstacle racing, before that Ironman Triathlon, before that water polo, before that body-building, before that I was a collegiate tennis player.

It’s just like life is a series of chapters and moving targets. It’s never just like one commitment to do one thing. But I would say, to give you a rough answer to your question, the very first time I decided to something a little bit more endurance orientated – which I would define as something that has a nutrition rate.

You don’t see people dropping out of baseball or cricket games because of fatigue and heat stroke and lack of nutrition. That’s very rare, but you see it all the time in marathons and Ironman triathlons and things like that. So I would say the first time I started to get into that side of sports would have been my first Ironman Triathlon that I did back in the city of Portalane, Idaho in 2007.

And up until that point I’d been primarily an explosive power athlete. Like body-building and tennis and stuff like that. But my girlfriend, who is now my wife, was a runner. She ran cross-country for University of Idaho. So I kind of had to take up running, to a certain extent, just to be able to woo her.

And she dragged me to a triathlon one day and she actually had me run the running leg of the triathlon, which hurt like hell. I was a body builder; my boobs were bouncing up and down and my lower back was locking up and it was horrible. But it kind of got me interested in this high that you can get from endurance sports.

And so I wound up doing a few triathlons and doing, what I would say, is the biggest mistake for anyone who wants to avoid getting into endurance, that is I went and watched an Ironman Triathlon. And after watching Ironman and watching these intense feats of physical performance and the huge feeling of satisfaction and self-completion that these people were experiencing as they threw up their arms when they crossed the finish line I was like, I want that. I want to experience that.

And so I signed up for an Ironman and began taking everything I had been studying. At that point I had a Master’s Degree in Exercise Physiology and Nutrition and I was able to start applying that stuff to my training, and experimenting with a lot of what I was finding in research and sports science and seeing what worked and what doesn’t.

For example, all laboratory studies, or most of them, done by the white coats in their little labs will tell you that the body can take on about 200 to 250 calories of fuel during exercise. You can oxidize 200, 250 calories of carbohydrates while you are exercising. But for anyone, especially anyone who’s above about 150 pounds who has tried to go out and do an Ironman Triathlon, you completely bonk after about five hours on that number of calories, and you technically need about twice that in order to be able to get by in an Ironman race in most cases.

So, it’s a situation where what they’re saying in the lab and textbooks actually doesn’t work once you get out in real life and you try this stuff in the streets, in the trenches. So, that’s been kind of fun too, figuring out from research what works, and what doesn’t.

[Damien Blenkinsopp]: Right. Yeah, we often talk on here about n=1 experiments are often going to be different to the research, for a variety of reasons like the ones you brought up, and the use of averages, and other things like that.

[11:24] So, anyway, in terms of endurance training, since we’re there, what kind of biomarkers have you found to be the most useful to track your performance? Or what do you track around your capabilities for endurance training, and see as important?

[Ben Greenfield]: Oh, for endurance specifically?

[Damien Blenkinsopp]: Yeah.

[Ben Greenfield]: So for endurance specifically, that’s a great question. So one would be your level of HSCRP, which really that’s just for exercise in general. Or high sensitivity C-reative protein, just to make sure that your levels aren’t straying too high above 0.5. And the reason for that…

[Damien Blenkinsopp]: So that’s kind of your benchmark? You try to keep them under there? Where do yours tend to hover around?

[Ben Greenfield]: I actually fall below 0.2 now for HSCRP, probably because I eat a very anti-inflammatory diet, very clean. And I won’t insult your listeners’ intelligence by defining what a clean diet or an anti-inflammatory diet is, because it’s pretty easy to go out and figure that out with Dr. Google.

But I eat very clean. I also use a lot of anti-inflammatories. Like I make ginger tea, and I use a ton of turmeric, usually combined with black pepper to increase the efficacy of it, and I use percumin and I consume a lot of very dark and colorful vegetables with very limited amounts of dark and colorful fruits, and wild caught fish, and fats, and things that really help with inflammation.

And I’m also very careful with my training, where I do extremely focused and intense, but short, bouts of training with a specific purpose. I never go out and just pound the pavement for the hell of it, which is a great way to build up a lot of voluminous training based inflammation.

And so I have a very precise, dialed in training program that also includes things that help to mitigate inflammation, like foam rolling, and cold soaking, and these things that can help to remove a lot of these byproducts of metabolism that can create inflammation. So, inflammation is a biggie. Honestly, it doesn’t take a rocket scientist to figure out that if you keep your inflammation controlled, it’s a good thing.

So, a few others that I’ll pay attention to for endurance. When we’re talking about labs, as far as blood goes, TSH, preferably a full thyroid panel, is pretty prudent to pay attention to simply because high level endurance training can inhibit conversion of inactive to active thyroid hormone.

And because of the high amounts of cortisol that can potentially be produced through an improper training program can stress the body out enough to where you experience some hypothalamic pituitary adrenal axis insufficiencies, particularly high cortisol, creating a feedback loop that reduces the conversion of inactive to active thyroid hormone and thus an increase in thyroid stimulating hormone. So your body turns out a bunch more thyroid stimulating hormone to try and get more T4 present, even though a lot of that T4 isn’’t getting converted into T3.

And by monitoring TSH, if you see a pattern or a rise in TSH many times it’s concomitant with an increase in cortisol and stress, and often also accompanies a not enough eating period. Sometimes not enough carbohydrates is the biggest culprit, but in many cases just not enough damn calories, period. Damn, not referring to your first name but to the curse word. Just so we’re clear.

That’s another one is TSH. Cortisol, I alluded to, but when we’re looking at a hormonal panel, I also like to pay attention to sex hormone binding globulin. Because the body has this interesting mechanism where when it’s stressed out, when it’s in a time of famine, in a time of need, under high amounts of stress, doing a lot of migrating, a lot of moving with low amount of calorie intake, the last thing you want the body to do is produce a bunch of babies at that point.

And so sex hormone binding globulin often rises simultaneous to cortisol to keep total testosterone bound, and keep it from being available as free testosterone. So even if your testes are working just fine, or your pituitary gland is working just fine, –obviously talking about the males more than the females now– and even the leydig cells in your testes are producing testosterone just fine, if sex hormone binding globulin levels are really, really high that’s all for naught. And so that’s another really, really important one to keep an eye on. And that’s typically addressed by addressing cortisol.

[15:50][Damien Blenkinsopp]: Right. So, why would you look at SHBG versus free testosterone, or that marker? The [unclear 15:56]?

[Ben Greenfield]: Well, because if free testosterone is low, but if you look upstream perhaps it’s because total testosterone is low because the leydig cells in your testes are not producing enough hormone because you’ve got low levels of luteinizing hormone. In contrast to that, perhaps your luteinizing hormone production is fine, your leydig cells are producing enough testosterone just fine, your total testosterone is high, but it’s more of a cortisol issue than it is a central nervous system issue or a glandular issue.

So that’s why you test that versus just looking at free testosterone.

[Damien Blenkinsopp]: So basically, free testosterone could be many, there’s more reasons behind it, but the SHBG is more specific to endurance and specific dynamic.

[Ben Greenfield]: Yeah. Really, two reasons behind it. Either you aren’t producing enough total testosterone, or you are producing enough total testosterone but it’s not getting converted. So those are really the two main things to look at.

[16:48] [Damien Blenkinsopp]: So, are you looking at the standard reference ranges for that, or do you look for something a bit more precise?

[Ben Greenfield]: A lot of times you have to look at symptoms synonymous, because standard reference ranges are going to vary widely.

I’ve worked with a lot of endurance athletes who have very high libido levels, show no signs of over-training, have very robust nervous systems, high heart rate variability, low cortisol, and even low sex hormone binding globulin, but their total testosterone is in like the high 300s. Which, for a body builder they would scoff at that and say, oh that’s rock bottom low. Even though a lot of times hypogonadism is levels below 100.

And you’ll get many people who just feel like fricking crap at 300, and some people will be closer to 500, and some people will need levels of 700, 800, or even 1000. So it kind of depends. It varies widely, I suspect based on genetics as a big part of it.

So ultimately it’s really tough to hold things up to reference ranges. I mean, you can ballpark it. You can say well if total testosterone is starting to get below 300, that’s where we would really start to get a little bit concerned. But it really is kind of tough. A lot of times it’s a moving target based off of a cluster of other symptoms.

If someone’s complaining of low libido and low motivation, and lack of energy, etc, and their testosterone is at 400, well that’s a pretty good sign that 400 is not going to be adequate for them. So I know that’s one of those deals where it’s total soft science, but it does really depend. That’s one of those ‘it depends’ answers, but that is definitely a variable that I will look at.

[18:20] Liver enzymes is another one, like alkaline phosphatase, aspartate aminotransferase, the ALT, the AST, some of these liver markers just because a lot of times they can be elevated when excessive exercise is present. And so that’s another one to pay attention to. It doesn’t have to be excessive exercise; sometimes it can be alcohol, pharmaceutical intake, things of that nature. But liver enzymes are the one that I’ll look at.

Kidneys, a lot of people say to look at kidneys, but frankly it’s very rare for me to see an athlete who doesn’t have slightly elevate creatinine and blood urea nitrogen levels, which are two common markers in the kidneys that a physician will get concerned about if they see elevated, but that are very common to see elevated if an athlete is exercising anywhere in the 48 hours leading up to a blood panel.

So, as long as creatinine levels aren’t much higher than about 1.1, and as long as blood urea nitrogen isn’t through the roof and – I apologize, but off the top of my head I don’t remember the lab reference ranges for blood urea nitrogen. The reason being that I do most of my coaching for blood panels with a company called WellnessFX. It’s basically more like a dashboard with graphs, more than it is hard numbers, so occasionally I’m looking at graphs more than I am numbers.

[Damien Blenkinsopp]: And they just have those red zones.

[Ben Greenfield]: Yeah, exactly. They’ve got red, yellow, green, which actually annoys me some of the time. Because they’ll flag high LDL as red when I purposefully try to get my LDL high. So there’s some issues with the whole red yellow green type of quantification. But anyways, blood urea nitrogen and creatinine, even though a lot of people talk about those, they’re not super duper important in my opinion, because they’re always going to be a little bit elevated.

Vitamin D, that’s another one that I’ll look at just because of it’s importance. As you can suspect, a lot of these aren’t just specific to endurance, they’re specific to exercising period. Just as a hormone and a steroid, vitamin D is another important one that I’ll look at.

And then as far as other things, I typically will have most of the athletes I work with or the people I advise do at least once a year a full gut panel. You know, a comprehensive gut panel that includes parasitology, measurement of pancreatic enzyme production, measurement of yeast and fungus and any type of bacterial overgrowth in the digestive tract because I find that, especially when you’re jogging your body up and down for 10 plus hours while racing, having a really, really good gut and GI system and very efficient digestion is incredibly important.

And so I will look at things like presence of yeast or fungus, like Candida Albicans, or the presence of H pylori, or absence of hydrochloric acid, or absence of pancreatic enzymes, or overgrowth of specific bacteria, or lack of short chain fatty acids in the digestive tract, in the colon, and a lot of those things that tend to influence an athlete’s performance or their feelings of well-being. So that’s another thing I’ll pay attention to.

[21:18][Damien Blenkinsopp]: Right. A lot of people wouldn’t think of that as something performance related, more like a chronic issue related.

Have you got any case studies where you saw people, basically not performing but not having any negative symptoms in terms of GI distress or anything that they would have noticed, but when you put through these tests some negative results came?

[Ben Greenfield]: Sure. Now we’re delving a little bit more deeply. And I mean, obviously explosive diarrhea halfway through a marathon can be a good sign of digestive enzyme insufficiency, but so can, for example, vitamin B12 or vitamin D deficiencies, or even if you go more advanced and run like an organic acids profile, or an amino acid profile, severe imbalances of a lot of micro-nutrients.

Well if you’re not digesting your food efficiently, for example, if you’re not producing adequate hydrochloric acid, you’re not activating pepsin to break down proteins, beginning in the stomach an moving on to the small intestine, then you’re going to: a. have undigested protein fragments winding up in the bloodstream causing some auto-immune issues, and that can include fuzzy thinking, which no athlete wants.

But then you also can get amino acid deficiencies, like deficiency in the ability to create neurotransmitters, and also deficiencies in the ability to repair and regenerate skeletal muscle tissue, because you aren’t breaking down the proteins that you’re eating.

And the same could be said for something like inflammation in the digestive tract from wearing down of the microvilli. So perhaps you’re not producing adequate levels of lactase, so you’ve got some lactose issues and bloating and gas. Or you’ve got inflammation that is resulting in malabsorption of fat-soluble vitamins, so vitamins A, D, E, and K aren’t getting absorbed properly, or bacteria aren’t helping you to produce those, and so you experience hormonal deficiencies, or steroid deficiencies.

And so, yeah the gut is incredibly important, and that’s one of the things I’ve been kind of getting on companies like WellnessFX, for example, to do is to not just use the strategy of blood testing but also really pay attention to the gut. I mean, in an ideal scenario, what I would like to see is a done-for-you system.

And for me right now, what I do is just kind of string this together for the athletes who I work with. But a done-for-you system where you get your blood testing, you get your gut testing, and you get your genetic testing so we can look at everything from genetic snips to bacterial imbalances in the gut to all the blood and biomarkers, and have all of that done with either one panel or one service.

That would be really nice, because right now you’ve got to go to typically three different places. You’ve got to go to whatever DNAFit, or 23andMe, and you’ve got to go to DirectLabs, or Metametrix for GI affects, and then you’ve got to go to WellnessFX for whatever else. And then if you want to do food allergy testing, well then you’ve got to throw in a Cyrex panel, or something like that.

So maybe it’s a first world problem to want all this stuff to be available in one central location, but it certainly would be nice.

[Damien Blenkinsopp]: Yeah. It’s so near the early days from that perspective. There’s a lot of specialized, it’s still kind of specialized in terms of the labs. Each is in their little separate box and everything.

[Ben Greenfield]: Yeah.

[24:17] [Damien Blenkinsopp]: So, in terms of the kinds of decisions you’ve made, or you’ve advised a client based on some of these values, some of this data that’s come back, what have been the biggest changes that you’ve implemented to optimize training?

[Ben Greenfield]: You mean as far as training?

[Damien Blenkinsopp]: So, say the TSH came up too high, what would you do about that?

[Ben Greenfield]: Oh okay, so for high TSH, obviously it’s never a shotgun approach. It’s never a multivitamin. So for high TSH it may be looking at your carbohydrate intake. That’s the first thing that I’ll look at.

Even before you look at total amount of calories, you just make sure nobody is on some low, like 40 gram per day carbohydrate diet, because frankly a lot of the ‘low carb’ or ‘ketosis’ based diets that are out there were created for sedentary people. Even the bulletproof diet. I love the whole bulletproof philosophy, but it was written by a computer programmer, not by an athlete.

And so the levels of carbohydrate, and even the levels of calories in that diet, have to be adjusted and modified for a hard-charging athlete, especially an endurance athlete. So, otherwise with caloric depletion and carbohydrate depletion, you basically lose a lot of your ability to convert inactive to active thyroid hormone.

And in the case of calories, as you would deduce through common sense, when you send your body a message that calories are insufficient but you’re still requiring it to move a lot, your body down regulates metabolism. And one of the main ways it does that is by down regulating thyroid.

So, I look at carbohydrates, I look at calories, and then I also look at dietary intake of organ meats and fat soluble vitamins, which can also assist with thyroid health. So in my case, because I did an n=1 experiment about a year and a half ago where I did 12 months of ketosis.

Not cyclic ketosis, not cycling carbohydrates in and out throughout the day, but full on eating only 5-10 percent of my total daily intake from carbohydrates. Very low carbohydrate diet. Too low, in my opinion, for most endurance athletes who want to maintain optimal levels of health elsewhere.

[26:10] [Damien Blenkinsopp]: Did you see negative effects from that over the 12 months?

[Ben Greenfield]: Yeah, and that’s what I’m getting at with the thyroid. I started taking thyroid glandular extract. I took one called Thryo-Gold, which is made from New Zealand cows, that are like an A2 cattle.

A lot of A1 cattle has proteins in it that cause an immune reaction within the human body, but cattle that are breed via A2 are cattle that contain this A2 genetic profile that is more bio-compatible with the human body. And so I basically took a T1, T2, T3, and T4 combo, and that seemed to turn my thyroid around. But that was after I had already done a number on it.

So for thyroid, that would be an example of what I would do with something like thyroid, would be increase calories, increase carbohydrates, increase intake of organ meats and fat soluble vitamins. And then for a really hard-charging athlete who insists upon doing something like restricting carbohydrates to tap into the performance enhancing effects of ketosis, understand that you’ve got to get on extra help from the thyroid.

Since your body isn’t going to make T3, dump it into the body. And preferably get it from a whole source, like levothyroxine or synthroid. But a source that contains other elements of thyroid in addition to just T3, so you’re not creating an imbalance.

[27:22] [Damien Blenkinsopp]: Great. Well, connected with the thyroid issues, I was wondering if you’ve come across adrenal fatigue also. If that’s every come up with you or with anyone else.

[Ben Greenfield]: Absolutely. Adrenal fatigue, gosh. There’s like four chapters of my book on that alone. But adrenal fatigue, well what do you want to know about it?

[Damien Blenkinsopp]: Well first of all, have you looked at some of the tests? I’ve done some of the salivary tests.

[Ben Greenfield]: Oh yeah. Yeah, like an adrenal stress index is kind of gold standard, cortisol DHA. If you look at the cortisol DHA curve, that’s much, much better when you’re addressing something like adrenal fatigue versus a blood cortisol measurement, which is just a snapshot. You want to see a moving target of salivary cortisol levels, preferably matched to salivary DHEA levels, throughout the day.

[28:03][Damien Blenkinsopp]: I was just thinking, based on it’s endurance exercise, and it has this tendency to raise cortisol, that that would be more of an issue and something that you would keep an eye on. Or by monitoring TSH, does that kind of take care of itself? If the TSH is alright then you tend not to have an adrenal issue as well?

[Ben Greenfield]: No, not necessarily.

You can still have adrenal fatigue and have a thyroid that’s managed properly. Because what you would typically see in that case is someone is eating boatloads of calories and taking care of themselves from an energetic standpoint, but simply outputting too much energy. They’re just training way too much. Even though they’re supplying their thyroid with what it needs, there’s just too much training still.

And a lot of times you’ll see inflammation high, but yeah. Cortisol DHEA, and that adrenal stress index can be a good measurement. And there are less quantitative measurements. You could do a pulst test, where you look in a mirror and you shine a bright light at your eyes, and your pupils should stay dilated. But if it stays dilated and then just starts flickering rapidly.

[Damien Blenkinsopp]: Have you tried that one?

[Ben Greenfield]: I have, yeah.

[Damien Blenkinsopp]: Because I was just wondering. I did try it and I find it a little bit difficult to judge.

[Ben Greenfield]: Yeah, it’s certainly not as precise as a salivary measurement, but once you’ve done it a few times you can definitely see the pupil, and whether or not it’s actually flickering versus staying dilated. If you look at if for long enough, it’s just going to start flickering period, but if it starts flickering after just a few seconds, that’s typically a sign that your kidneys are not producing enough aldosterone, which is synonymous, or can accompany, adrenal fatigue.

The other one is just the dizziness test. If you lay down or you sit down and you stand up quickly and you get dizzy, that can be a sign of blood pressure mismanagement that often goes hand-in-hand with adrenal fatigue. And again, these are the super cheapo poor man’s methods, but it can give you clues.

And then there’s temperature tests for thyroid, the Broda Barnes Temperature Test, where you do oral and axillary measurements of your temperature in bed every morning, and keep a running graph. And if it’s consistently low, that can be a pretty good indication that even if you haven’t done a blood thyroid test that your thyroid might be having issues.

So, there are a lot of things. One of the best ones I like though is just pure heart-rate variability. Testing the interplay between your sympathetic and your parasympathetic nervous system by using something like a Bluetooth enabled heart rate monitor and one of these heart rate variability apps, and simply paying attention to whether heart rate variability is high or low on any given day.

And if it’s consistently low, and you see consistent suppression of both sympathetic and parasympathetic nervous system feedback, then that can be a pretty good sign that you’re on the cusp of adrenal fatigue illness or injury, and so that’s another really good one to pay attention to. And I do that one every day myself.

[Damien Blenkinsopp]: Do you do it in the morning as soon as you wake up?

[Ben Greenfield]: Yes, that’s gold standard, because that’s where most of the studies have been done on heart rate variability were five minutes resting in the morning.

[30:45] [Damien Blenkinsopp]: Right, right. I believe you use the HR…what’s the name of the company?

[Ben Greenfield]: SweetBeat?

[Damien Blenkinsopp]: Yeah, SweetBeat.

[Ben Greenfield]: Yeah, but because I want to build up that technology and add some features and stuff like that, I’ve actually white labeled their technology. And so I use the app called NatureBeat now, but it’s the SweetBeat technology.

[Damien Blenkinsopp]: Great, great. Yeah, she’s been on the show.

[Ben Greenfield]: Yeah.

[Damien Blenkinsopp]: So I was using that for a long time, and then I just recently started using iFleet, because I also talked to the guys at iFleet, and it does have this other thing that they just added recently. You might just want to check out.

It’s kind of interesting. It shows how high your energy levels are on a given day, so it kind of does this matrix thing. So it shows you if your in the bottom right corner, it means something a little bit different. So I’ve been checking it out. I’m still trying to understand what it means each day. But I do find that when I’m at the bottom, low energy, those days tend not to be good. Even if I have a high HRV.

[31:39] So anyway, out of interest, what is your HRV levels? Because you think normally endurance athletes have higher HRV, right?

[Ben Greenfield]: Yeah. Usually higher HRV, which isn’’t necessarily a good thing if you’ve got what are called HF to LF ratio imbalances.

You want your HF to LF ratio to be pretty close to one. That’s sympathetic and parasympathetic nervous system feedback. And if parasympathetic nervous system feedback, which would be your high frequency number, if that’s super duper depressed, and your LF is really high that can be an indication of aerobic based over-training, or vice versa.

So ideally you’ve got high HRV and a pretty close to a 1-1 ration between HF and LF. That’s what you want to go to. And you want both HF and LF to be up in the thousands. That’s a sign of a really robust nervous system.

So, my values tend to be between about 92 and 98, with HF and LF values that vary between about 4,000 to 8,000, around in there. Generally with a 1-1 ratio, depending on what my previous day’s training had looked like.

And I would expect, for example, this Tuesday I’ll do a CrossFit’s Murph and I’ll do that with a 20 pound weighted vest on, and just crush myself. And that will take me about an hour to do, and I guarantee my LF value will be tanked the next day. But I also won’t be doing any sympathetic nervous system training for like 48 hours afterward.

[Damien Blenkinsopp]: So you recover within 48 hours?

[Ben Greenfield]: 48 to 72 hours, depending.

[Damien Blenkinsopp]: These scores recover for you pretty quickly?

[Ben Greenfield]: Yeah, but I mean, if I were to do something epic, right? Like, usually something that gets you to the state of glycogen depletion. Or let’s say instead of Murph, I do double Murph, or I do a Murph with a 5k sandwiched on either end rather than just a mile, then it can take me several days to recover, for sure.

[33:23] [Damien Blenkinsopp]: If you had to pick one marker to optimize your endurance training by and make decisions on, which one of the ones we’ve talked about would it be?

[Ben Greenfield]: HRV.

[Damien Blenkinsopp]: Okay, great.

[Ben Greenfield]: Just because it’s easy, right? You don’t have to give blood.

And maybe at some point, once we’ve got the lab and chip technology finalized, and I can put a drop of blood onto a little dongle that will plug into my iPhone and I can measure, let’s say, testosterone cortisol ratios, maybe that will become a more valuable metric for me. But at this point, I would have to say something simple and easy to utilize and relatively inexpensive, the HRV would be the one that I’d choose.

If I had to choose an actual blood biomarker, tough to say. Tough to say. I guess I’d probably have to go with HSCRP, again. Just because inflammation is generally going to be high when cortisol is high. It’s generally going to be high when diet is crappy, it’s going to be high when triglycerides are high, it’s going to be high when omega-3 fatty acids are low. So, that’s a pretty good one to measure.

[Damien Blenkinsopp]: Yeah. So it catches a lot of things. Mainly whenever something starts going wrong.

[Ben Greenfield]: Yeah.

[34:29] [Damien Blenkinsopp]: Well so you’ve referred to over training quite a bit over this as something that you’d have to change. So HRV would be one of the first places you’d see over training.

Are there any other tell-tale markers, and what do you suggest, more to the point, because you mentioned earlier that you do very – is it short, intense kind of endurance exercises. And I think a lot of people when they’re thinking about endurance, they’re thinking about very high-volume, kind of long duration activity.

So how do you approach it, and avoid over training? What are the top things you’ve taken in over time?

[Ben Greenfield]: First of all, one of the common pitfalls that people fall into with endurance training is doing the long voluminous training every weekend. It’s very stereotypical that you’ll see in a lot of athletes these Saturday long bike rides and then Sunday long run, for example. Or in a marathon, the Saturday long run.

I’ve found that in most cases, you can maintain endurance really, really well. Unless you’re a professional athlete trying to perform at the peak of performance, most people can perform just fine. With doing digging into the well like that, really, really, deep for like a death march, a really long ride or something like that, you typically only need to do that one to two times a month. Not every weekend.

I’m a bigger fan of using shorter, very temporal based intervals. So to give you an example, for the Ironman triathletes that I work with, while their peers are out doing a five hour ride followed by an hour long run, my athletes will be doing two hours of 20 minutes at race pace followed by 5 minutes recovery. So a very focused activity with a specific goal in mind. And then they’ll finish that up with a 15 minute tempo run at a cadence of 90 plus.

So it’s all extremely high quality. And then once a month they’ll go out and do something big, something long, something voluminous that builds the mental tolerance to training, but that doesn’t dig so deep into the well as doing it every week.

And the reason for that is based off of the human body’s natural slow twitch muscle fibers. The human body’s ability to cool because we’re upright and not covered in fur and hair. Our ability to sweat, rather than pant, to reduce heat. And a cluster of other factors.

We’re pretty good at going for long periods of time. And when training for endurance, bigger limiters are things like power, speed, cadence, strength, the integrity of the fascia connective tissue, the intelligence to be able to use nutrients and calories properly.

And really pointing in one direction, and going for long periods of time is not that much of a weakness for the human body, but the problem is that it’s easy. And people take pride in it. They’re like, “Oh I persevered today. I did my three hour run.”

And my question to you is well yea, but what did you accomplish side from being on your feet for long periods of time? Which frankly I could stand up at my standing workstation and write an article for three hours and get the same amount of time on my feet as you just did out pounding the pavement. So it would be better in that case to do something with intervals at race pace for a shorter period of time.

Focus on cadence. Allow enough time before and after for a good warmup. Maybe some meditation and breath work. Some good recovery. And so that’s where the more intense, more quality, lower volume approach nine times out of ten trumps the voluminous approach.

The exception to that fact would be the person who has a lot of time on their hands to train: the professional athlete. Professional athletes, assuming they’re using this 80-20 approach, it’s called polarized training. 80 percent of your training is done aerobically, with about 20 percent done high intensity.

That approach works very well, and it is what a lot of the elite cross-country skiers and marathoners and cyclists etc. will use, but what is important to understand about that approach is it requires many, many hours per day.

That approach can require two to four hours per day of training, and even more than that, on weekends, for example. And the majority of folks simply don’t have the luxury of time available to utilize that approach effectively. That in a nut shell is my approach to training.

I’ve got a couple of athletes who I work with who are more, what I would consider to be on the professional level, who have that luxury of time. And I do train them with that aerobic approach, where they’re out doing long voluminous sets of training at a controlled heart rate aerobically, putting lots of time in the saddle or time on the pavement. But its very few and far between that I’ll recommend an athlete to train like that.

[Damien Blenkinsopp]: Great, great, thanks. That’s a great summary of it.

[39:01] I wanted to move on to, because I know you did this 12 months of ketogenic dieting. Could you talk a little bit about that? Give us an overview. What was your approach to that, what were you actually eating, and was there any specific goals to track over the year?

[Ben Greenfield]: Well yeah, for that specific diet, that was for a study at University of Connecticut that was done on, basically, a group of athletes who followed a high-carb/low-fat diet, versus a group of athletes who followed a high-fat/low-carb diet.

And it was basically a measurement of fat oxidation during exercise. And they also did muscle biopsies before and after exercise to see the rate of glycogen use as well as the rate of glycogen replenishment following the post work out meal to just see if the body does a better job at oxidizing fat, or at sparing glycogen during exercise when you’ve eaten a high-fat diet.

And it did turn out in that study that the athletes who followed the high-fat diet were oxidizing a lot of fat. The textbooks tell you that you can burn about 1.0 grams of fat per minute, and the group of athletes who followed the high-fat diet were burning 1.5, 1.6, 1.7 grams of fat per minute. Literally rewriting the textbooks when it comes to how much fat you can burn during exercise.

I haven’t seen the muscle biopsy data yet to see how much glycogen conservation actually took place, or whether or not the body became more glycogen depleted when using primarily fatty acids as a fuel. But ultimately, what that diet consisted of was really controlling carbohydrates.

Whereas I would normally – and this is what I do now – I would carb-cycle, or I would do cyclic-ketogensis or cyclic-ketosis, where I don’t eat carbohydrates all day long and at the very end of the day, typically in the post-workout scenario, with dinner I’ll eat anywhere from 75 to 200 grams of white rice, red wine, sweet potatoes, sourdough bread. You know, safe starches, not like pizza and ice cream, but good carbohydrates. And then the rest of the day just high fat and moderate protein.

Whereas on this full on ketosis diet, it was pretty much just things like bulletproof coffee, and high fat shakes and lots of coconut milk and coconut oil, and heavy cream and MCT oil and seeds and nuts, and just fats, fat, fats. Bone broth and avocados, and olives, and you name it.

And frankly, in my opinion, it wasn’t that enjoyable to have to not have sweet potato fries, and not have, even coconut ice cream has cane sugar in it. So you have to make your own with chocolate stevia. And so it’s a little bit laborious and a little bit tough, but I mean at the same time the endurance payoff was huge.

The amount of focus that I had for long periods of time. My ability to just hop on a bike and ride for hours with no fuel at all, with just water. It was pretty profound, because you produce all these ketones as a bi-product of fatty acid oxidation, and they’re used as the preferred fuel by the brain, by the heart, by the liver, by the diaphragm while you’re out exercising. And that’s a huge boon to an endurance athlete.

And like I mentioned, there’s some blow-back. Like the TSH could take a hit, the testosterone could take a hit. But ultimately, it’s a cool little bio-hack. If I could go back and do it over again, I would definitely start taking thyroid glandular earlier to stave off some of those thyroid issues.

I would,– it’s not legal – but I would really encourage folks to pay attention to testosterone. And I mean like, you can’t use testosterone in a WADA, or a USADA or like an NCAA sanctioned event, but my testosterone dropped so much during that experiment with ketosis, I would say if you’re not competing, use AndroGel or just some kind of testosterone support because your testosterone is going to fall to pieces.

And then the question becomes well is it really worth it to you if you’re doing this thing and you’re not even competing.

[Damien Blenkinsopp]: Yeah. Did you feel different?

[Ben Greenfield]: Oh, yeah.

[Damien Blenkinsopp]: Because we talk about testosterone with things like anxiety, your drive, your libido, of course. And so did you get any kind of low testosterone symptoms?

[Ben Greenfield]: Oh yeah. Absolutely. I mean even something as simple as only having to shave every four or five days, whereas normally I would just shave every one to two days.

[Damien Blenkinsopp]: That’s a benefit.

[Ben Greenfield]: I mean, little things like that, but you notice. Yeah, potentially. You save money on razors.

Yeah, the libido, sex drive, number of times having sex per week, desire to have sex, quality of the erection, all of those kind of things certainly they took a hit during ketosis. They weren’t good. But that was, mind you, ketosis in the presence of high amounts of physical activity. Even doing the ‘low volume approach’ it’s still a massive amount of work, right?

[Damien Blenkinsopp]: Right.

[Ben Greenfield]: You’re still working out 60 to 90 plus minutes every day, and longer than that on the weekends.

And you look at something like Dr. Terry Wahls and her ketosis approach for managing MS. Well sure. I mean, that’s going to work just fine for managing MS. I mean, going on a walk with your dog every morning, and maybe lifting easy weights, three sets of 10 for 20 minutes twice a week.

But once you jump into hard exercise, it’s a whole different type of ketosis.

[Damien Blenkinsopp]: Right, right. Just to be clear, were you getting better times? Did you feel like you were competing better?

[Ben Greenfield]: Oh, I was competing way better. Yeah. Absolutely.

[Damien Blenkinsopp]: Right. But it’s just the downsides to your lifestyle, to all the other things, were too great to do this on a constant basis.

[Ben Greenfield]: In my opinion, yes, because I don’t like being cold all the time, I don’t like not having libido. So again, I’m not saying you can’t do it properly, even though it’s way, way tougher once you get into training, but I think that you basically have to use supplementation pretty intensively.

[44:34] [Damien Blenkinsopp]: Did you kind of see the benefits evolve and get much better as the months passed, or is this something someone could do on a month basis, one month on and one month off?

[Ben Greenfield]: For exercise, you barely even see any benefits until you’ve been doing it consistently for about six months, and the real benefits start to manifest after one to two years.

But the other thing to realize is that right about the time I finished up the experiment, companies like KetoForce started coming out with beta hydroxybutyrate salts that could be consumed to elevate your ketone bodies, even in the presence of a lot of carbohydrates or glucose. And so it’s possible that now, since the experiment that I did, you could get the best of both worlds.

And I actually have some bottles of the beta hydroxybutyrate salts and the resistance starches, and a lot of the things that, if I had to go back and do it all over again, I would try to get the best of both worlds. I would eat more carbohydrates, but then I would also hack myself into ketosis by consuming actual ketones bodies.

The question there becomes a matter of long term health and gut health and how that actually manifests in terms of actual symptoms or the way you felt, or even I would definitely pay close attention to blood and biomarkers.

Were I to delve into that type of bio-hack? I potentially may. I could see myself, and obviously I’m at a point in my athletic career where I’ve still got a good eight years of hardcore performance left in my body, and I could see one of those years being spent utilizing a ketonic approach again, but with the incorporation of beta hydroxybutyrate salts, resistance starches, even higher amounts of MCT oils, particularly like the C8s and the C10s. And a little bit more attention paid to ways to get into ketosis that go above and beyond just carbohydrate restriction and exercise.

[Damien Blenkinsopp]: This is great Ben, this is a wealth of information.

[46:20] In terms of the biomarkers you would track, you said you would track some biomarkers if you were going to do this again what kinds of ones that we haven’t spoken about already would you look at? Did you track your blood ketones?

[Ben Greenfield]: Yeah. Breath ketones. I mean, urinary ketones become, many times, absent after a few weeks in ketosis just because you’re utilizing your ketones. Blood ketones are accurate but expensive and invasive to test, and breath ketones are pretty [easy].

There are breath testing monitors like the Ketonix device that, one breath and you know your ketones, and you’re good. So breath testing is a really good way to go as far as measurement of ketones. You look for values anywhere from 1.0 up to 3.0 millimolars. You’ll finish exercise as high as 7.0 millimolars.

You’ll rarely see ketoacidosis, which would be like 10 plus millimolars. It is a non-issue. I have yet to see any athlete I work with go under ketoacidosis, which would be an actual deleterious biological state. Not something you need to worry about unless you are letting yourself become severely hypoglycemic.

[47:20] [Damien Blenkinsopp]: So again, is that something you saw evolve over the months? Like your ketones ratings would get higher.

[Ben Greenfield]: Yeah. You get to the point where it’s just super duper easy to get into ketosis. Yeah. And your ability to go for long periods of time without eating just goes through the roof.

So ultimately, the biomarker I would say, in addition to what we’ve already talked about, would be breath ketones. And then pay attention to triglycerides too, because they’ve shown that compared to total cholesterol values, a better predictor of your coronary disease risk factors is your triglyceride to HDL ratio, specifically keeping that at one or lower in terms of your number of triglycerides versus HDL.

But I’ve found that some people will switch to a high-fat diet and have such a high intake of vegetable oils, and even an imbalanced high intake of animal based oils, like butter for example, versus olive oil and avocados. Their triglycerides go through the roof.

Pay attention to that HDL ratio. That’s my advice is make sure that that thing isn’t getting much above one, that would be another important thing to pay attention to, especially on a higher fat intake.

[Damien Blenkinsopp]: Great, great. Excellent points.

[48:25] So there are a couple of other things I’ve noticed you’ve done in your experiment. I read your book of course. One of the things that we’ve come across before – I spoke to Alan Cash from benaGene –oxaloacetate, and I was wondering what you’ve done with that and if you’ve tracked anything or learned anything about that.

[Ben Greenfield]: Yeah, obviously if you talked to Alan Cash your listeners can go back and listen to that to learn more about what oxaloacetate is. But in a nutshell, the reason that I used it was because it can increase the turnover rate of lactic acid into pyruvate, and increase the rate at which lactic acid is shuttled back up into the liver to be reconverted into glucose.

And so if you are eating a low-carbohydrate diet anyways, that by nature means you might not be taking as much exogenous glucose in, or might not even have as high a level of glycogen stores, but you can still take the lactic acid that you’re producing as a byproduct of metabolic activity anyways and have that reconverted into usable glucose sources to have a glycogen sparing effect and to get a little bit more intensity. And so the way that would be achieved if you’re going to increase the rate of that cycle, which is called the Cori cycle, would be via the use of oxaloacetate.

And so, I actually did use that. I don’t use it right now. It’s one of those things where it’s just like, I would benefit from it its just one more supplement to remember to take. But I certainly used it through that entire ketotic experiment with the oxaloacetate just to increase the conversion of lactic acid into glucose.

[Damien Blenkinsopp]: Right, it sounds like it would help specifically in that ketogenic diet state when you’re exercising.

[Ben Greenfield]: Exactly.

[Damien Blenkinsopp]: So you designed it that way? You decided to take it before, or was it something you came up with afterward to help?

[Ben Greenfield]: I talked to Alan at one of the Bulletproof bio-hacking conferences. We talked about the physiology of oxaloacetate, and then based on that I just kind of had a little light bulb moment, where I realized that if I was restricting carbohydrates anyway, that this was one more way that I could create endogenous glucose more quickly.

[Damien Blenkinsopp]: Great, great.

[50:27] Cold thermogenesis. Do you still play around with that? Is there anything like, for instance, have you seen your HSCRP any time, potentially when you first started it or did it a bit more intensively, change with that?

[Ben Greenfield]: Yes. I have not done a dedicated experiment with cold water exposure, cold temperature exposure, or the use of ice baths or cold showers to see the direct effects on HSCRP, although reduction of inflammatory cytokines has been observed in literature when it comes to cold thermogenesis and inflammation.

What I use cold thermogenesis for is increased conversion of white adipose tissue to brown adipose tissue. Simply because it’s very difficult to kill fat cells, but you can convert fat cells into energy utilizing and heat producing tissue. And that’s one thing that cold thermogenesis is good for. That would mean cold baths, cold showers, cold soaks, etc.

Also very useful for increased production of endothelial nitric oxide synthase, which can cause your blood vessels to dilate much more readily, which is good for everything from exercise to sex to heating your body when it needs to be heated. And then there’s also increased tolerance to the mammalian dive reflex, which is that activation of our sympathetic fight-or-light nervous system in response to stress.

And when you are able to withstand cold stress without taking that sharp influx of breath, that means that you have become more resilient and more resistant to subconscious activation of that fight-or-flight nervous system. You’re better at controlling stressful events that happen.

And so, what I do is I never take a warm shower. I do a cold shower in the morning, cold shower in the evening. I do once per week a 30 minute cold soak that gets me up to shivering level, typically needing to shiver for one to two hours afterward in order to regain warmth. And those are the ways that I use cold thermogenesis. I also keep my house relatively cold. My office is at about 55 degrees. In my home, typically I’ll sleep at 60 to 65 degrees.

It’s just a really, really good way to make yourself tough, to burn fat, and to increase blood vessel health. And it’s just super simple. And frankly, the other cool thing is when I go hunting or when I have long periods of time outdoors or when I’m at the beach and evening comes and I forgot my coat, I don’t get as bothered, which is just kind of nice. You’re just more tough.

[Damien Blenkinsopp]: It sounds like the only time it was an issue when you were doing you ketogenic thing. What was the issue there? Were you getting a lot colder, or?

[Ben Greenfield]: Yeah, but that was because of the thyroid. If you have hypothyroidism, cold thermogenesis is going to be very uncomfortable. Heck, even normal temperatures you’re colder during. So I was still doing cold thermogenesis then but it was quite unpleasant. It was hard for the body to get warm again.

[Damien Blenkinsopp]: Okay. Right, great.

[53:17] Some quick fly questions that I have just to finish off here.

First of all, if people want to connect with you and learn more about you and what you’re up to, where is the best place? Twitter, your website?

[Ben Greenfield]: Bengreenfieldfitness.com, because if you go there, you’ll find links to my Twitter, Facebook, Instagram, my blog, my podcast, etc. So that’s a good place to go as a portal.

[Damien Blenkinsopp]: Great, great. And who besides yourself would you recommend to learn more about endurance training, or some of the other topics we spoke about today? Ketogenic diets and so on?

[Ben Greenfield]: As far as people who have their head screwed on straight who are paying attention to the research, I’d say three people come to mind.

Number one would be Joe Friel. He’s coached a lot of professional cyclists, but also has just been in the sport a long time and pays attention to the science and the research and has a pretty good unbiased view of things.

Sami Inkinen, who is a top age group for Ironman competitor. He’s a higher fat diet, pays attention to quantified data, and is a smart, well spoken person who performs well.

And then Dr. Peter Attia, who I would not say is on the pointy edge of physical performance, even though he’s in much better shape than the average, general population. He’s not out doing Ironman triathlons or anything. But, as far as the science goes, he probably knows the science better than just about anybody else when it comes to being able to speak to these things, and he also does quite a bit of self-quantification himself.

So, those would be three people that would be good resources for this.

[Damien Blenkinsopp]: Great, thanks so much for that.

[54:48] Beyond everything, like all the biomarkers we’ve spoken about today, are there any other biomarkers you pay specific attention [to] on a routine basis, I don’t know whether it’s monthly –that you feel are important that we haven’t spoken about?

[Ben Greenfield]: I’ll finish with this because it’s important. And many times in our type of circles it’s not talked about, and it’s not quantifiable to a great degree, as far as I know. And that would be simply paying attention to your levels of gratitude every single day, and multiple times per day.

For me, I guess you could kind of quantify it – at least six times per day I’m grateful. Because I’m journaling, and at the beginning of the day I journal three things I’m grateful for, and at the end of the day I journal three amazing things that happened to me that day. So there’s at least six times per day that I’m being grateful for things.

And then I practice quick coherence technique, which is something you can read about at heartmath.org, which increases heart rate variability and decreases stress. And that’s where you simply think of something that you love or someone you hold dear, and you imagine intense feelings of gratefulness washing over your body and going into your heart after you feel those feelings of gratefulness.

Saying thank you to people, saying I love you to people, randomly calling up people and telling them how much you appreciate them. If you listen to my voicemail, I ask people to end their voice message by telling me one thing that they’re grateful for that day.

It’s certainly something that’s not super duper quantifiable, again, but it is one thing, not a biomarker, but certainly something I pay attention to every day is gratefulness for being alive, for the people in my life, for the experiences that I’ve had, and for simply being able to take one more breath.

[Damien Blenkinsopp]: Excellent. Thanks for that, that’s not the typical, but definitely something really important. So I can see how that would be useful. I do a meditation gratitude every morning too, and I find that really, really useful.

So Ben, thanks so much for your time today. It’s been really stock full of biomarkers and hacks and everything, so it’s really been a great episode. Thank you for your time.

[Ben Greenfield]: Awesome. Well thanks for having me on, Dam.

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This episode is about experimenters in the field of biohacking, the people actually in the trenches doing stuff. We’re focusing on wearable devices such as watches, shirts, bracelets, necklaces and on and on.
We’re focusing on wearable devices such as watches, shirts, bracelets, necklaces and on an on. Basically, anything that you can put on your body that can give you data on your performance.

Wearables are here to stay and there are more coming out to track different aspects of our biology, of our health and our fitness, and so on. Which of these devices give us the most accurate data? How can we make good use of the data and improve our lives instead of just letting all those numbers cause confusion and distraction?

“You really have to get this intersection of who is the user. How much data do they want? Are we giving them enough data and is it accurate data?”
– Troy Angrignon

Troy Angrignon is an emerging technologies consultant with expertise in marketing strategies and segmentation for wearables. Troy spends a lot of his time testing several of the latest wearables while doing a range of relatively extreme athletics and feats, including military style training like that done by SealFit. He reviews and compares the products then maps them all out into big ‘x and y’ diagrams simplify data and make test easier to understand.

The show notes, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

Show Notes

  • Troy’s interest in wearables started with early generation sports watches that could tell the user how much recovery time they would need after a particular workout. (4:05).
  • Improvements in utility of wearable devices over the past 10 years from sport watches to fitness trackers, to activity trackers to smart watches. (6:25).
  • Value of wearable tech depends on the user’s activity level and goals – Troy Angrigon’s 5-tier approach ranging from the semi-active user who needs little more than a watch with a timer to measure how long or how fast they ran to the pro athlete looking for clinical data. (7:33).
  • Devices currently available that cater to the tracking needs of elite-level endurance athletes: Garmin 920Xt and Fenix. (11:10).
  • Discussion of accuracy of wearable devices – Damien notes that tests have shown the degrees of error to be roughly the same between manufacturers. (13:10).
  • Devices currently available that are accurate enough for optimizing performance at a high level (17:10).
  • Problems with current software that misinterprets sedentary activity such as watching t.v. and reports it as sleeping. (20:32).
  • Fitbit Surge design advantages – combines GPS with optical heart rate monitoring (21:42).
  • Design areas where Troy Angrignon thinks manufacturers are excelling: Fitbit has good tracking for lower level users, Jawbone offers good customer service and good apps, and areas that still need work: understanding the customer, how they live and what they are going to use the tool for. (22:45).
  • Devices for lower activity level users: Fitbit, Jawbone and Body Media (23:47).
  • Devices for mid-level users: Fitbit Surge HR, Garmin Vivoactive, Garmin FR620 (27:14).
  • Devices for high-level users: Garmin 920XT, Fenix and Epix models (29:10).
  • Platform compatibility issues between manufacturers – users with several devices from different manufacturers can’t pool or cross correlate their data easily(29: 58).
  • Application issues with EEG devices: Muse, Emotive; collect data but few apps have been developed for converting the data into usable or actionable information. (30:40).
  • Meditation as a tool for improving mental and physical performance. Damien mentions using meditation in conjunction with the Muse (32:05).
  • Discussion of sleep tracking devices for different user/quantification levels: level 2 analysis reports how many hours in bed and of that how many hours spent sleeping vs. tossing and turning; level 3 reports deep vs. light sleep phases, records snoring, level 4 provides clinically verified data, level 5 provides raw sensitive data. (35:04).
  • Troy and Damien describe techniques they’ve each used to improve their sleep quality: cover bedroom window with blanket to darken the room, turn off all screens, programmable lights; devices to use: Basis, Jawbone, Fitbit Sealfit Unbeatable Mind, Lumen Trails. (39:48).
  • Price ranges of wearable devices (50:00).
  • Risks associated with EMF exposure from wearable devices. Damien mentions that most people aren’t aware of potential detrimental health effects of EMF’s. Topic is discussed in the book 4-Hour Body by Tim Ferris. (52:55).
  • Sleep coaching tool: Sleepio.com. Troy mentions this tool, which educates the user on the complexities of sleep and identifies the user’s particular sleep issues. (56:30).
  • Troy Angrignon’s prediction for the direction wearable device technology is going in the next 5-10 years: we are currently at an immature stage in being able to collect and analyze data. He hopes we can compress the maturation period of this technology and not have to wait 30 years until we can turn data into actionable intelligence (57:55).
  • The biomarkers Troy Angrignon tracks on a routine basis to monitor and improve his health, longevity and performance include sleep via Sleepio.com, heart rate variability with the Garmin Forerunner 920xt and recovery levels through RestWise.com.
  • Troy Angrignon’s one biggest recommendation on using body data to improve your health, longevity and performance is to decide on the one thing that would make the biggest difference to you and track it.

Thank Troy Angrignon on Twitter for this interview.
Click Here to let him know you enjoyed the show!

Troy Angrignon

The Tracking


  • Sleep-Related Biomarkers: Measure sleep in total time (hours and minutes) and percentage of time spent in different sleep phases:
    • REM (Rapid Eye Movement) sleep : Characterized by random eye movements and is physiologically distinct from non-REM phases of sleep. Troy mentions that the Basis watch measures the amount of REM sleep.
    • Deep Sleep: Characterized by slow, synchronized brain activity and is the most restful phase of sleep. Mentioned by Damien in relation to inability of the Basis watch to track properly.
    • Light Sleep: Also known as stage 1 sleep, a non-REM sleep stage that forms the transition from wakefulness into deeper stages of sleep. Mentioned by Troy in context of the Basis sleep tracking watch.

  • Heart Rate Variability (HRV): Mentioned by Troy as an indicator for over-training. HRV is a physiological phenomenon whereby the heart rate changes to accommodate physiological, mental or emotional stressors.
  • VO2 Max: Mentioned by Damien as a test available through fitness labs. Measures an athlete’s maximum oxygen consumption rate and is used to gauge aerobic fitness levels.

Lab Tests, Devices and Apps

  • Colored LED Lights: Damien mentions using these to help with sleep.
  • Apple Watch: Smart watch with fitness tracking capability.
  • Basis Watch: Smart watch with sleep tracking. Mentioned by Damien for its inability to distinguish sleep from sedentary activity.
  • Beddit: Sleep tracking device. Troy mentions that version 1 was offered in consumer or pro models, with the consumer model being cumbersome to operate.
  • Beddit Misfit: Under mattress sleep tracker.
  • Body Media Fit : Mentioned by Troy as having a loyal customer base. Strap-on style device worn on arm.
  • EEG (electroencephalogram) Devices : Measure brain wave activity, used to determine sleep cycles. Mentioned by Damien in relation to tracking sleep.
    • Emotiv: EEG monitor Troy mentions that he hasn’t tried yet.
    • Muse Headband: Contains an EEG device.

  • Fitbit Products
    • Fitbit Surge: Fitness watch that offers GPS tracking, heart rate monitor, all-day tracking, sleep tracking, and wireless syncing. Troy mentioned it in relation to its optical heart rate detector.
    • Fitbit Charge HR: Fitness watch with automatic monitoring.

  • Garmin Products
    • Garmin Fenix: Mentioned by Troy as a durable device, good for competitive and endurance athletes.
    • Garmin Forerunner 920xt: Mentioned by Troy as a durable device, good for competitive and endurance athletes.
    • Garmin Vivoactive: Good for running, cycling and swimming but not able to track transitions in triathlons
    • Garmin Epix: Similar to the 920XT and Fenix plus a larger screen with high-reolution color and apps.

  • Jawbone Up : A line of activity trackers. Mentioned by Troy as being problematic for its clip-on style and not being waterproof.
  • Lumen Trails: Tracker app Troy uses to simplify tracking for many things.
  • Sleep Tracking Devices
    • ResMed S-Plus: Sleep tracker with connections to Phillips Corp.
    • SleepRate: Sleep tracker mentioned by Troy as having a different scoring algorithm than Jawbone.
    • Sleepio: Sleep tracker mentioned by Troy in relation to its scoring algorithm.

  • Restwise: App Troy uses to track post-workout recovery.
  • Suunto: A Finnish manufacturer of measuring instruments that carries a range of sport watches. Troy mentioned their products as having excellent hardware but cumbersome software.

Other People, Books & Resources


  • Dr. Greg Welk: A Kinesiology Professor at Iowa State University where he oversees the Physical Activity and Health Promotion lab. Listen to Damien’s interview with Dr. Welk on the accuracy of fitness trackers in episode 18.
  • Dave Asprey: author of The Bulletproof Diet Mentioned by Troy in regards to brain training for increasing focus and blood flow to the pre-frontal cortex.
  • Ben Greenfield: Mentioned by Troy in relation to sleep improvement tips. Maintains a fitness website and blog.
  • Ray at DCRainmaker.com: Triathlete who maintains a website and blog. Mentioned by Troy for his extensive product reviews.
  • Dr. Kirk Parsley: Sleep clinician for Navy SEALs. Associated with performance program called Sealfit Unbeatable Mind.



  • The 4-Hour Body: The book by Tim Ferriss mentioned by Damien in relation to health effects of EMF’s.

Full Interview Transcript

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[Damien Blenkinsopp]: Troy, thank you so much for joining us on the show.

[Troy Angrignon]: Hey Damien. Thanks, great to be here.

[Damien Blenkinsopp]: So, you have the absolute, most comprehensive review of wearable technologies, wearable devices I’ve ever seen. It looks like something from my consulting background years where I was paid big money to create those kinds of things.

So when I saw it I was like, yeah I definitely have to get this guy on the show. He’s put so much time and effort to looking at it from a user; what people actually need and the functionality out there. How did you get into this? Where did your interest in wearable devices start from?

[Troy Angrignon]: I’ve always been interested in them. I’ve always looked in the very early days at running watches, all the sport watches in the early days. The Suunto’s and the Garmins’s and things like that and even in the early incarnations, you could see some kind of cool things that were happening.

They would have interesting features in them. It would say, ‘you have to recover four hours after this workout’ and then say, ‘oh wow, that’s really cool. How are they figuring that out?’ So I got interested in some of the early sport watch stuff and really followed it through that. I’m a nerd and kind of a geek in general.

Anyway I like data. I’ve been involved in data based industries and loved doing sports. It really came from probably the sport watch side of things in the early days.

[Damien Blenkinsopp]: Great. So how long have you been doing this because the sport watch has been around for quite a while now?

[Troy Angrignon]: They have, right. Probably ten plus years and I really got into; I’d say what we know as this current generation of wearables or near-ables. You want to use that phrase.

Really about four years ago when I started looking at sleep issues; I was having sleep issues from working on a start-up and getting no sleep, and all those things. So I started looking at better sleep practices, a lot of stuff that you and I both went through in the bio-hacking space.

And looking at sleep practices as well as tools, so I started looking at a lot of tools and from there that was kind of the beginning. I think you were probably very aware of it at the same time. The sleep tools were happening and the activity trackers were starting to come out and things like that. That was probably 2011, 2010?

[Damien Blenkinsopp]: Right. Absolutely. What it is though, is sleeping activity is a big area? It’s interesting. Have you got a lot of data from over ten years reflected from all of these watches and things?

[Troy Angrignon]: No. Especially in the early days a lot of it, it’s hard to get the data off or it just comes off into space and you could look at it on some desktop application or something. So no, I think my largest, continuous data set is probably three years. I was just looking at it actually, all my workouts, probably for the last three years.

It’s spotty. There were sections where things didn’t track or I lost data or whatever else. Probably the last three years has been pretty rigorous.

[Damien Blenkinsopp]: I think you’re probably got pretty much on top of what’s been actionable and what’s been most useful for you over that time. How have you seen the curve of utility go up for you personally, because obviously you’ve been testing different devices and it’s been ten plus years?

In the beginning, was it useful or was it like trying to get some value out of this and getting a little bit but not so much? Like how to use scales on like one to ten, how has it changed over the last then plus years?

[Troy Angrignon]: Well I think two things have changed. There’s how have I changed. I own an approach to thinking about the data and I’ve kind of gone through my own levels of maturity in thinking about it. And then the technology, of course, is changing.

You and I have talked about this before where I kind of do think in that ‘x and y’ and I think that the market has evolved. We’ve gone from just sport watches to now, we’ve got fitness trackers, activity trackers and I can get into definitions of those things. Smart watches.

Some of the fashion companies; they’re with traditional fashion watches are now getting into smart watches. And so you’re getting this kind of bigger fragmentation and more features being developed. At the same time as what I want data has definitely changed and matured and mutated over time. So it has been definitely a change in both ways.

[Damien Blenkinsopp]: Great. Thanks. And who do you see is getting real value from the wearables tech on the market today? I mean you can take yourself as an example. What are you getting real value out of today and who else do you see getting real value out of these wearable tech today?

[Troy Angrignon]: That’s a tough question. I think a lot of different people of different skill sets can get value and it really comes down to what they are trying to do. So I think, maybe it will help set the stage probably for the rest of the call and give us a framework. Why don’t we talk through what we discussed the other day?

But I tend to think of user types as kind of a zero to five in a very gross, coarse way. So a zero would say, ‘I don’t care about data. I’m not going to use any of these tools. I’m just going to go run. I want to just feel the wind in my hair and get outside.’ Where a one would start to ask for some data, like I just want a watch that shows me the time. Like how long did I run? How far did I run? Maybe something basic.

A two would say, ‘well I want that but I want a little bit more data. Give me a few more fields.’ And a three really starts to say, ‘I want to know my time, my splits, my cadence, my running dynamics, my vertical oscillation. They start to get pretty technical in terms of what they’re looking for.

And the fours, they’re really looking for that. They want it to be trusted. They want to know that the data that they’re getting in those devices or applications truly is actually legitimate data. Where the threes are ok, just give me the number and I’ll kind of look at the numbers Is it going up or going down. I don’t really care if it’s super accurate.

And then the fives, you’re really talking Olympic athletes to that point. You’re talking people getting clinical, grave data. And so if you think about kind of the levels and you can apply those levels to the level of athlete too; zero probably doing nothing, one just starting, a two sort of semi-active, a three quite active, four pro-amateur level and five being a lead athlete.

And so if you think about those levels and then you think about what they do. Is this a wellness client who’s saying, ‘I just want to feel better, eat a little better, lose a little more’ or are they kind of a fitness type person that’s saying, ‘well I jog a bit, I run a bit, I cycle. I do a couple of things, I dance, I do yoga whenever. Or they’re really starting to get into the endurance in space.

So, I do run. I do marathons. I do long distance cycling. And then all the way up to what I call to the right on my charts where you’re beginning to know super competitive endurance and ultra-distance stuff. And ultimately you’re getting into like the outdoor, backcountry stuff where they’re like, ‘I’m going to go, put my watch on and go ten days into the back country.’

That’s a different animal. It’s a different kind of an athlete. So I tend to think of it kind of an ‘x by y’. And that’s a long back story to answer your question. But I think that people from, kind of the ones to the fives, on the y axis. And then everything from the sitting on the couch and just trying to get a little more active, all the way to the outdoor backcountry folks.

There are pockets of people in there who are getting a lot of value but I think it’s less about them and less about their specific technology and more about the process. So, are they clear on what they’re trying to figure out? Have they chosen the right tool? Does the tool give them the data and can they look at the data and have a feedback loop and say, ‘ok, I got what I needed. I’m going to improve my running speed or I’m going to back off and train less hard because I’m over-trained or whatever else.’

So, that’s a really fuzzy way of saying some people are getting useful stuff out of it and a lot of people are just looking at stuff and they don’t know why.

[Damien Blenkinsopp]: Right. And what we were talking about is a critical need the other day. You were talking about competitive athletes who want to shave off a few seconds off of their times or whatever.

This is critical needs and I guess these are the guys that would be using the fours and the fives that exist today. What kind of devices out there are there that provide that level of detail today, if there are any?

[Troy Angrignon]: Yeah, up in the competitive endurance space. I would look at, these are folks who are doing pretty aggressive, marathons, triathlons, cycling races, multi-sport, even obstacle course racing, which as you know is pretty popular these days, Spartan racing, those kinds of things.

And it’s less about those sports and more the level at which they compete in them. So we’re talking upper 50 percentile, upper 25 percentile folks. Now we are either looking at their times, very aggressive about their times. So once you get into those environments, your use case is pretty tough for a device manufacture.

You can throw a FitBit on these people. And then a lot of my friends bought Jawbones or Fitbits or whatever. What I would can an activity tracker, meaning something with an accelerometer in it and they last about a day because you get them wet, you cover them in mud, you get them in the ocean. Whatever happens, they short out.

So those kinds of users that are really competitive and endurance athletes, they’re hard on their toys. And they really need devices and apps, in fact they don’t even carry their phone with them cause they just trash them. So, you’re really looking at things like Garmin 920xt’s are a great example in the triathlon space or the Fenix, which is the new Garmin in the Fenix Backcountry watch.

Suunto has some excellent hardware, although their data is really hard to move around so I’m not a big fan of them for that reason. So yes, there are definitely tools that work in that space.

[Damien Blenkinsopp]: Great. And in the general where do you see most people using today? Is it in the level one? We were talking with Greg Welk who’s done ongoing studies on the accuracy of these devices and we got into this discussion of how they’re not accurate, most of them to varying degrees. They’re biased.

However, they’re roughly the same wrong every time. So you can check, the relative is difference to what you did yesterday. Consistently one direction wrong or the other so you will talk about the usefulness of at least I know had more activity or I was faster than yesterday at the very least. Is that how you look at that whole area right now? I mean it’s more of a relative difference you can use it for.

[Troy Angrignon]: Absolutely. And again, think of the ones to fives. Kind of drawing a picture in your head of kind of the ones to fives on the left side and then really the bottom of the chart, consumer wellness on the left and all the way through fitness, recreational endurance, competitive endurance and outdoor tactical on the right.

And so I think your question really gets to who uses these, let’s say activity trackers, like Jawbones, Fitbits, these little things that you can clip on. I don’t like clip on ones cause you just throw them in the wash and lose them and break them.

But let’s say the bands you can put on. And you nailed it; they’re not that accurate but if you’re a one you don’t really care. All you’re looking for is step data. And so, did I move a little bit more than I did yesterday? Is it consistently capturing the step data? Is it good enough?

And I have met so many people who say, ‘oh I’ve got my first one and I love it because I used to do 2000 steps and now I do 3000 steps.’ And does it matter that it was 3500 or 2500? No, it’s irrelevant. What they know is they a feedback loop which gives them some objective measure and it’s better than what they had before, which was nothing.

So I think that there’s still a lot of value there. There’s a really interesting company I was actually looking at it yesterday after you and I talked. Diva Metrics I think is the name and I think they’re in Montreal. I may have the city wrong, or Calgary.

And they’ve gone through a really rigorous analysis on how inaccurate all these tools are and making data correction tools. So they’ll say, ‘well this thing is 92% accurate so we’ll just take the data and just up it by the requisite 8% to reality.

[Damien Blenkinsopp]: That’s interesting.

[Troy Angrignon]: So, it’s pretty cool.

[Damien Blenkinsopp]: They can be selling that to the companies who design the devices.

[Troy Angrignon]: So I think there’s still a lot of value in just having some kind of indicator. Calories, I could go on a rant about calories for days. The shorter version is that I think calories in and calories out is a dead model. But a basic summary, whether it’s steps or calories, is it a number that’s higher or lower than it was yesterday.

That’s a great indicator for people that just didn’t have awareness of that before.

[Damien Blenkinsopp]: It’s definitely kind of how serious you are about doing what you’re doing. So if you take an example of sleep. That’s what we were talking about this last time and we’re both fans of sleep, obviously.

I was really interested in the Basis Watch when they were bringing the sleep tracking out because I wanted to understand my deep sleep versus other areas of sleep. And I really just wanted to know I was hitting my eight hours that I wanted and trying to push it up to nine for a while.

I was pretty disappointed because it was saying I was asleep a lot of the time and I wasn’t able to trust that data because if I was sitting around watching TV, or even working on my computer sometimes, it would be like yeah you were asleep in the middle of the day.

So I couldn’t actually use that for just an estimate of how long I was asleep and because I didn’t trust that, I didn’t trust how much it was saying I had in deep sleep either. I didn’t feel like I could do any of the experiments, like to increase your deep sleep because that’s one of the things that I was interested in doing.

I gave up on those experiments and trying to optimize that. By having these biases, it really limits the kinds of experiments and what you can do. If we’re just trying to get a little bit better, like say with the activity trackers. Its fine, we just want to make sure we’re moving. The Basis Watch I’m sure, loads of others, you can point out would be ok for that.

But if we want to actually go to the next stage and optimize it to another level, to a higher level, a more competitive level and get more out of that performance, whatever that angle is. If it’s sleep or running, it’s not quite there yet.

Or are there devices which you feel are there in certain areas, whether it’s sleep or running or areas where you can really optimize pretty well and move to the next level?

[Troy Angrignon]: There are and it’s interesting and I’ve really been wrestling with this a lot. I’ve looked at and broken everything out there or bought and given it away. I’ve tested pretty much everything I’ve ever written about.

You can definitely get more data. You just gave a great example with the Basis and it’s a bit my favorite whipping horse because it’s got some weirdness in the way they develop product. But essentially they try to give these really advance, what I would call QS level, quantified self-level for type of graphs.

A graph is pretty complex and you would expect a person in a pretty deep understanding of visualization and data analytics in order for them to use it. But yet a whole watch was really aimed at couch to 5k, people who are walking and maybe cycling.

In fact, that’s all it will even track, actually. It will self-identify activities. And then in the sleep arena, as you said it had things like deep sleep, REM sleep, light sleep and activity but everybody I know who has one said, ‘yes, they always tell me I’m sleeping when I’m sitting at the opera,’ which is probably true but that’s not relevant.

I don’t really want it showing that I’m sleeping at the opera. Or I’m watching TV or I’m sitting down to dinner. It was trying to do automatic sleep categorization. We’re running into really tough to build hardware and software that does auto-sensing and auto-identification of activity, whether that’s sleep or running or cycling or anything else.

You tease apart all of these issues, what it really comes down to is, as a vendor these guys have to get together and say, ‘well who really is our user and what level are they at? What use case are they using it for? Are they a triathlete and if they’re a triathlete, are they a one, two, three, four, or five?’

In my view, I know triathletes who don’t use watches. They literally just have a Timex. They don’t care about anything else. They don’t use complex sport watches. I would call them almost a QS-1, a quantified self-level one, but serious competitive triathlete.

You really have to get this intersection of who is the user. How much data do they want? Are we giving them enough data and is it accurate data? There’s this really complex landscape out there, which you and I talked about. This is why people are so confused right now.

[Damien Blenkinsopp]: Your charts are amazing. It’s amazing how many devices are there, already. And there is obviously a lot of money going into this space. What I guess is interesting is if you take the Basis as an example, again and I guess the Apple iWatch which is coming out.

Applications like that are trying to give people at home a very generic tracker, which is going to have a broad spectrum of things it’s tracking. But it sounds like you’re saying that just because the hardware isn’t there yet in terms of actually getting data from us, that the software can’t handle figuring out what we’re up to.

If you’re trying to track everything like are you asleep, are you moving, what are you up to, all of these kinds of things, yet the hardware isn’t accurate enough to be able to take that data and use some software to interpret it.

But if, like you said, we focus on a narrow use case, where the conditions we understand a lot more closely because it’s just one area of use rather than trying to track someone’s whole life. And that’s working and you can see that it’s possible that we can get there this time even though the hardware is not quite there yet. Is that kind of your viewpoint?

[Troy Angrignon]: Yes. I think it’s a reasonable summary, especially when we started with things like 3D accelerometers. They really don’t do much. They just give you rotation and space and G-Force, and that sort of stuff.

It’s pretty hard to extract really clean signal out of that and figure out what the heck is really going on. Is this person running or jogging or doing cycling. That was a big issue. There just wasn’t enough data or the sensors were even terrible and there weren’t enough of them.

Then we started to do things like, a great example I think that I was quite impressed by, is Fitbit Surge, their new heart rate based one. It has GPS for location, it has optical heart rate on the back, so it’s shining right into the skin, in the tissue just above the wrist and reading your heart rate which is pretty challenging to do.

They have the 3D accelerometer and they can use all of that combined so the GPS will be shut down. It will say, you’re not moving or it will actually just be shut off. It will say heart beat is low and there is no motion in the body and it’s late at night.

So it’s starting to get easier and easier for them to identify that you’re going to sleep and to pick that pattern out, or to just show that you’re active. I can see you’re active. Your arm is moving, your body is pumped up and I’ve got a lot of very heavy heart rate, sustain heavy heart rate. You’re probably doing something.

Now they don’t try to self-identify, which I think was the right move. You can mark it and tell it that you’re doing yoga or doing a workout. I think it’s all trending in the right direction.

[Damien Blenkinsopp]: So if you were would like to point out on the landscape right now what manufacturers are doing right and what needs work, in specific areas, where is your pet peeves and where are the areas where it’s doing a really good job?

[Troy Angrignon]: I think my biggest pet peeve across the board is just not understanding your customer. It goes back to what I said a few minutes ago. Know who your customer is. Know how they live and what the use cases are that they are going to put the tool through.

That really helps the vendor narrow down to what features does it have to have, how rugged does it have to be, how much battery life does it have to have. I have not been traditionally a fan of Fitbit. I know they are the 800 lb. gorilla here in North America. I think they had 67% of the market share in 2013 and I’m not sure that’s a ’14 number, but they have a broad spectrum of product.

[Damien Blenkinsopp]: So which devices do you see as being the most effective, the best buys right now, doing a really great job for users?

[Troy Angrignon]: Again, it depends on who you are, but I think there are some ones that are standing out. Moving left to right again and from ones to fives, lower left to upper right if you keep that chart pictured in your head that we talked about earlier.

The folks that want to just get a little more active than they were or they’re lucky to move a little more, track a little more and ones and twos in terms of tracking and they’re not really hard on their toys. Any of the new Fitbits (they’ve launched a whole new line) I think are doing a pretty good job.

They’re number one for a reason. I think what’s going to be interesting in that space is Jawbone. Jawbone I lost and or broke and destroyed a bunch of them and they were very good in Customer Service and kept sending me new ones.

I like their apps. They’ve got a good partner network. They’ve got a new one coming out; the Up 3 and they’re actually integrating some of the technology they bought from Body Media and I know that people who have Body Media’s, you can’t pry them off of their cold dead bodies.

It’s pretty interesting. They are rabidly loyal fans. That was the big one you strap on your arm basically. A lot of people are really attached to that and so they’ve taken some of that technology, like the bio impedance sensors and things and put it into the new Jawbone Up 3. I haven’t tested it but I have a pretty strong belief that they’re going to do a pretty good job at that low end of the activity tracker section. It will be interesting to see and that should be out March or April.

[Damien Blenkinsopp]: With those two devices, what kind of things do you think people could reasonably do? What kind of functionality are people thinking they just want to know they are doing more? How far do you think they can push those devices and get useful decision making out of them, using them to maximize something?

[Troy Angrignon]: You really can’t do a ton. They do basic activity tracking. They basically show you how active are you; you’re active parts of your day. They’ll give you calorie data and it’s totally inaccurate, so I wouldn’t use that. I would use the steps as just an indicator like you and I talked about. Am I doing more or am I doing less? That’s really what you want to look for, just for trend data day to day.

The Fitbit has sleep tracking. The low end of their stuff you still have to push a button or mark it. I think that’s a non-starter. That’s not sustainable because people forget. As you move up into their new ones like their Charge HR, which stands for heart rate and a Surge HR which has a screen and also does heart rate, you’re getting into more into the fitness tracker space.

Now you can track your day to day activities, see trending patterns. You can actually auto-sense your sleep or it will auto-sense your sleep. It’ doesn’t give you very deep sleep data. It just shows you are you restless or are you awake or are you asleep. It’s really three states essentially

If you’re really a nerd like you or I and you want to see deep sleep and light sleep and all that, it really doesn’t do that. Jawbone actually has always done that, although they’ve only done it through the 3D accelerometers. I’ve never really trusted that data.

With the inclusion of the new stuff, the new technology they bought from Body Media, I suspect they’re going to start to be able to pick up because they can sample the heart rate through the night and do things like figure out your morning resting heart rate which is a nice thing to know.

So I think that’s going to be an interesting entry in the higher end of that low end, if that makes sense, the activity trackers. And then as you get into the middle range, I’d say fitness folks who are doing a couple of sports, maybe they dance or running or the odd bit of cycling, but nothing ongoing, then the Fitbit Surge HR.

I sound like a Fitbit rep which is funny because I’ve never been a big fan. But I think they’re doing a good job and you can mark different sports. It’s pretty good actually. The accuracy is even surprisingly high when I cross reference it to some of the higher end tools I use.

Really to me, it’s kind of one of the only successful ones in that middle of the road fitness tracker space; Garmin is releasing something called a Vivoactive which will be squarely in that spot. It’s for running and cycling and swimming but this is a key point- not for triathlon because that’s a whole other use case where you need to connect those sports together in a block, like a swim and a transition and a bike and a transition and a run.

That’s a multi-sport thing which really you find at the high end. So I would say in the fitness tracker stuff in the middle, you’re looking at the Fitbit Surge HR, maybe the Garmin Vivoactive. I have not tested it. I’ve seen it and I’ve used it and I find the touch screen a bit finicky.

Maybe the Garmin FR620, which is their running watch, is pretty nice in that space; clear, bright screen, auto-upload on WI-FI and Bluetooth. So literally you do your run and then that’s it. It just synchronizes and it sends the data up which I think for these things to be sustainable, all of this stuff has to happen automatically.

You and I talked a lot about that. It’s like how much overhead can we take away. We shouldn’t be saying to the user, ‘you need to mark sleep, you need to do this, you need to do that.’ We’ve got enough on our plates. They don’t want to adopt a baby. It’s not a Tamagotchi watch.

I think that the watch can do, the better. And then at the high end, definitely these days I would really lean to the Garmin lineup. They release three new ones at CES, the Consumer Electronic Show, which I was quite impressed with because I think they’ve done a very good job of understanding the use case.

They’ve got a 920XT for the triathletes and multi-sport folks, a Phoenix which is that plus the backcountry stuff and then their Epix, which is all of that plus a great big screen with high-resolution color and apps on it.

I think the Fenix and the 920 are the winners out there because they’ve got the same thing; auto-upload on WI-FI and Bluetooth. And to me the big deal is data. Is it automatic, is it easy to use, is it automatic, does the data go somewhere and can you get the data to other places. Does that make sense?

[Damien Blenkinsopp]: Yes, absolutely. There are different platforms, like the Basis is a closed one, or not?

[Troy Angrignon]: It’s an island and so is Suunto. They’re off in space, Timex is the same thing. And anybody who’s an island, it doesn’t make any sense anymore because people have something like, I’m making this number up, but crazy numbers of 20 or 30 fitness apps on their phone and they want all that stuff to connect.

[Damien Blenkinsopp]: And it’s also a trust factor I think. Because with the Basis you can’t extract the information so where do these numbers come from. So I think there’s also that angle when you’re talking about people who are getting more involved in it.

They can’t take the data off of it. They’re wondering what the data is inside of it and how it’s calculated and things like that. I know that’s been a big frustration with Basis users. Another interesting model is the Muse, like the Muse Calm, they had that EEG device where basically you have an open API and they’re bringing this hardware to market and anyone can connect to it, develop aps on it, although no one seems to be doing that yet, so I’m wondering how that’s going to go.

[Troy Angrignon]: I talked to Muse and have not used the Muse. The Emotive is another one. And any of these EEG things essentially they are saying it’s something you put on your head. It’s this thing that looks like it’s from the future. It has all these touch points on your skull and it picks up your brain waves or brain wave patterns.

I think the big question I always have is, to do what. What’s the application and so I understand you have the hardware and I understand you have some kind of open API application programming interface, some way for me to get the data out, but ultimately what am I doing with it.

I tested another one. I picked up one from Dave Asprey’s Bullet Proof site which was a brain trainer, focus trainer which is ostensibly teaches you to move more blood flow in the pre-frontal cortex. I have it and I could actually do it. It’s actually pretty cool because you can put this little film on and you can fly over the mountains and you can actually control it with your brain, which is really cool for about ten minutes.

[Damien Blenkinsopp]: But it was, I was at this bullet proof live conference so I did it there and it’s a lot of fun but it’s a nice fast game. It’s not integrating with your life I guess. It’s something like meditation that you have to take time out for.

[Troy Angrignon]: which I’m a huge fan of. I think meditation, I do it every if not every day, every second day. I know a lot of people, especially athletes who are really, really find that critical piece of their training. But I don’t think that these tools are necessarily getting you there.

I think they’re kind of early attempts to say, ‘look at the pattern in your brain’ and you’re like, ‘great, what do I do with it’. I don’t know what to do with that information.

[Damien Blenkinsopp]: My personal experience from the Muse so far, I’m meditating every day and I’m using that. I’m playing around with different things and different types of meditation, for instance.

Dan [unclear 0:32:45:5] and so on, and I have managed to shift it. Basically you have an index . You don’t exactly know what that is so that’s a bit worrying to me because it’s their index that they’ve given you.

[Troy Angrignon]: Again, it’s another made up number

[Damien Blenkinsopp]: Rather than some standard that you can rely on more easily. So I think that’s another concern I have about a lot of these devices. Some of the manufacturers come up with an index which is 1 to 100.

It’s not based on any standard and you’re left wondering, I hope it’s doing what I want to because otherwise I’m spending of time meditating and hoping that I’m getting better but I might actually be getting worse.

I definitely want to dig more into what that data means and how it’s calculated. Now I’ve spent enough time on ‘I have to get around to looking at this’. So I think people have that concern at this stage too. And it’s kind of this transparency thing again. If you can just pull the data off and you can see exactly what it is then it would give you that comfort factor.

[Troy Angrignon]: Well, let’s step through that though, back to the beginning of the conversation. A level one person, in this case a quantified self, level one person, they only want that number because they don’t really know and don’t want to know the complexity underneath the numbers.

So I understand why the manufacturers do that, to look at the slave tools. They’ll give you a score. Your sleep score was 85%. Now Jawbone’s sleep score is not the same as Sleep Rates sleep score, or Sleepio’s sleep score. Those are all different sleep scores. And they have different algorithms underneath.

Some are transparent, some are not. But ultimately the user just wants to know, ‘hey it was 85 yesterday, its 90 today’. I’m trending up and that’s a good thing. And they’re good, that’s fine as long as that’s all they want then they’re already ok.

But I think you and I, we’re not ones. You’re definitely not a one. You’re a five.

[Damien Blenkinsopp]: Hey, you’re a five too.

[Troy Angrignon]: I’m a five, you’re a five.

[Damien Blenkinsopp]: Don’t stop for any fives around.

[Troy Angrignon]: So, we’re not that user and I think we need to be cognizant that a one doesn’t want the level of data that you and I want. And that’s ok because they’re just in a different place. And it doesn’t mean also that we’re a badass athlete and they’re not.

You can find world class athletes who are ones. Who are like just give me my Timex watch, I don’t want to know anything else. So I think that those are two separate dimensions. So to get to your point, yes, a lot of people are doing these roll up scores.
In my mind that’s a thing you deliver to the users who are ones and then if you’re delivering product to be also available to the twos, the quantified self, level twos, then you say, ‘hey, here’s your sleep score. It’s 85%.’ Underneath that means is, you were in bed eight hours but only six and a half of that you were sleeping and an hour and a half of that you were tossing and turning.

That’s kind of a level two analysis. And a level three analysis would be; well actually you had deep sleep, light sleep, here are the different phases. Here’s how many times you were interrupted and maybe here’s a recording of you snoring. Sleep rate does that, which is a little bit creepy.

And a level four would be that plus all of that is trusted, absolutely, clinically verified. And then a five would be the raw sensitive data. Put me in a lab and hook me up to 50 machines, which I’m sure you do.

[Damien Blenkinsopp]: I’m tempted. I haven’t done it as much as I’ve wanted to yet. I bet you’ve been doing it for a long time.

[Troy Angrignon]: No, I do actually show up to something with three or four devices on me. I was at a heart zone training session in this last week and I showed up with all of these devices on my arms and everyone was like, ‘why do you have so many watches’.

[Damien]: Because I don’t trust anyone of these.

[Troy Angrignon]: I’m cross referencing them all.

[Damien Blenkinsopp]: Which one do I trust today. Just out of interest, you were talking about labs, you’ve done VO2 Max or any of these kinds of measures. I know you can go to fitness labs and do those kinds of things.

[Troy Angrignon]: No surprise. I love to do more of that lab type testing. In fact, I’m actually doing one this week with a start-up that’s in stealth mode around heart zone training and threshold analysis. I would love to do more of that.

Most of mine has been with these consumer grade tools. Really just looking to see which one is the most accurate of the bunch because I am not at the level with my own training and with my own coaches where I need to be within, for heart rate threshold analysis, I don’t need to be within one beat. It’s not material useful for my training.

[Damien Blenkinsopp]: For most of my stuff I’m there. I’d say like the most critical thing I have is sleep. And I’d really love to know exactly how many hours I’m sleeping. And it’s more, for me its accountability. It’s just like if I get a little alarm and it’s like you only slept five hours the last few days, then I’m going to act on it. That’s the big thing and that will change my life, just that little thing there.

[Troy Angrignon]: I think it would change everybody’s life. I fell into this rabbit hole. You and I both came to this from having health issues. I was having sleep issues. That was my big thing at the time. I’m sure a lot of your listeners know your back story.

So I came into it from the sleep angle of going, ‘man, I’m not sleeping,’ and I’d like to prove that. I learned a lot from the bio hacking community and the bullet proof executive and Ben Greenfield and all of these guys.

And I was like, ‘ok, I need to make the room black and I need to go to bed early and turn off my screens at night’. All the stuff that we now know is good sleep discipline. There is another word.

[Damien Blenkinsopp]: Sleep discipline is a good word because all of things take a little bit of effort to do them, that’s all. Once you’ve got a routine and you’re doing them, then it’s great.

[Troy Angrignon]: Right, and so coming into it I think that everybody kind of vectors in on these things like what is your one thing that you’re working on. Actually, that’s a good thing to talk about here which is, what is your one thing? What’s the one thing you want to change the most?

Do you want to increase your time or do a race and just finish or do a race and be top ten? Or just sleep better? And that helps you pick the universe of possibilities of things you might use as a tracker, maybe you just pick the one thing that will help you get to that step and don’t try and boil the ocean.

[Damien Blenkinsopp]: So you’re saying don’t just try to attempt to track everything? When I got the Basis I wanted to have it all. I’m not picking on Basis here, it’s just that when I happened to jump on to it a couple of years back so I had the most experience of it. And it didn’t do that and the Jawbone or the Fitbit didn’t do it at the time. So what you’re saying is decide that one thing and that’s going to decide what device you get and you’re going to get that value out of it, if that’s the most important thing to you, whatever you want to change.

[Troy Angrignon]: Right. And I think that that’s a really good object lesson for all of us. I’ve been through all of these things so I ultimately I always come back and think about it. Now that I’ve tested it and I can talk to other people about it, that’s fine. But for me, what am I working on next and therefore what is the right tool for me, today or this week?

[Damien Blenkinsopp]: Well cool, let’s talk about some quick case scenarios then and the market and where it is today. What would you do? Let’s start with sleeping. If we’re just trying to improve our sleep or get some accountability behind it, which device would you choose right now, and you think it would do the job? Would you think it would do the job?

[Troy Angrignon]: Yes. So I wouldn’t even get a device. Actually I would just listen to Ben Greenfield’s podcast that he did, a long presentation, a bunch of Q&A that he did at Sealfit Unbeatable Mind, I think you and I talked about Sealfit. He was down there for a conference. He’s published the podcast and it’s an excellent podcast. I highly recommend it.

[Damien Blenkinsopp]: Cool, is this on sleep or is it Q&A?

[Troy Angrignon]: Well inside there he has this whole how to bio hack your whole life. He goes through 4000 things you can do and so many at the end rightfully said. ‘Look dude, my brain exploded. Where do I start?’ And he came to the same thing. He was like, ‘pick one thing. Pick one area that you would like to improve, one metric in that area and look for the right tool.’

To go back to your question, the right first device to fix your sleep is not a device. It’s reading up on the basics of sleep, understanding what good sleep discipline is, doing things like blacking out your room. Maybe the first device is a big hairy blanket you hang from your window. That’s probably the best device. The cheapest thing that you can buy that’s going to have the biggest impact.

[Damien Blenkinsopp]: You’re laughing about that but that’s exactly how I started. I just got a big furry blanket and I’m guessing you did too. I had come to visit my parents and I all of a sudden read this stuff. This is years ago and I grabbed a blanket and put it up and they were like, ‘what the hell are you doing?’ And they really didn’t like it because it’s just not done, I guess.

[Troy Angrignon]: Somewhere I read was like, ‘tinfoil doesn’t pass any light through’, so I completely tin foiled my window and the very next day the building manager came up and said, ‘you need to take that down, you look like a crazy person.’

[Damien Blenkinsopp]: Some of these things, if you go this route, is a pain to take down. Otherwise you just leave it up. You’re like, ‘well I’m not in that room during the day anyway.’ But other people aren’t so [unclear 0:41:56:3]

[Troy Angrignon]: Exactly. I think there’s a lot of work and we don’t need to go down that. This is more about devices. There are a lot of things you can do. I would say black out the room, put things like ‘F LUX F. LUX’ on your computer at night. It dims the screen. There’s a lot of stuff about not having blue light at night. This is all well documented at Ben Greenfield or Dave Aspreys Bulletproof podcast.

[Damien Blenkinsopp]: Well the one thing I have done, because I didn’t trust the Basis data, was I have this little tiny app which tracks all manor of things. It’s just like a little tracker app. It’s called Lumen Trails. There are probably plenty of others like that, but for some reason three years ago when I started tracking a lot of stuff, that was the one out there.

And it just allows you to put data in and it just allows me to press a button which says I’m going to sleep and then when I wake up, press it again and now I’m awake and then I know how long I slept. That’s really the most reliable measure I had and I’ve got huge chunks of data like months where I was doing that.

And I found that useful although it’s not automatic, it’s a pain. But at least it gave me some kind of register. Because I found out I really don’t know sometimes what time I, especially if was tired if I went to sleep, I won’t really remember at what time I went to sleep and what time I’m waking up unless I’ve actually gotten it written down somewhere.

[Troy Angrignon]: And I think you just nailed it. You’re a very quantified guy and it was still a pain and we need to get away from that stuff. This whole thing of you have to click a button, it doesn’t matter how small that motion is, we have too much going on to make the users do that.

I’m coming back to being a PR dude for Fitbit here, but I think the Charge HR does this as well but I know that the Fitbit Surge HR does this. It just automatically figures it out and unlike Basis, which would say I slept five blocks of 30 minutes, which is just insane.

The Fitbit Surge actually does a really good job of saying, you went to bed now and you got up then and it was eight hours and you were actually asleep for six and a half. It doesn’t give you any depth below that, so it’s kind of a quantified self, level two answer.

Eight hours with six and a half with real sleep inside there and there are no phases or anything else, but it’s automatic. I don’t have to think about it. I’m quite willing to make that trade off because I could get more data but then I would have to think about it and I don’t want to think about it. I have enough tools in my life.

[Damien Blenkinsopp]: And for 99% of people, that data is going to be actionable. That’s going to tell them what they need to know.

[Troy Angrignon]: Absolutely. Because you can look at it and see, ‘oh well, gee, I got four hours, four hours, four hours, four hours. And it actually displays your actual sleep time. So it’s been showing me things like three and a half hours. I’ll be in bed for five or six and it will say three and a half. What do you mean three and a half?!

It’s showing the actual time that I’m not moving and I’m really dead to the world. I have to laugh about that. I think finding a basic device like that is good, but something that’s automatic I think is also helpful.

If you have real sleep issues, sleep is a really critical issue and we are all as a population lacking in good quality sleep, I think this is worth investing time and energy and focus on, because it improves everything. There’s hormonal issues and weight loss and moods, just a million things. In my book it’s foundational so I think it’s the place everybody should start.

[Damien Blenkinsopp]: Sleep and meditation I think, are the two things that I want to get done every day. We are always thinking about these huge lists of task, but I’ve really tried to start putting these two things at the top. So if I don’t do anything else at least I’ve slept and I did my meditation.

[Troy Angrignon]: Yes, if more people would prioritize that. Down at Sealfit Unbeatable Mind there’s a really great fellow there, Dr. Kirk Parsley. He is a Sleep Clinician for Navy Seals and he said, ‘my biggest challenge is, a) they don’t sleep that much because they’re training all the time and b) I have a hard time in getting their heads around the fact that sleep is fundamental and foundational to everything they do. And that lesson is not just for them. That’s for all of us.

[Damien Blenkinsopp]: So you fixed your sleep. What did you find that the main things were that you’re doing and that worked for you just since that’s something that you worked on a lot?

[Troy Angrignon]: The big things were I had to make changes at work. I had a very great team that I was working with at the time and I said, ‘look these are all the things going on and we need to shift some stuff.’ There were work changes, darkening the room, putting timers on my phone that would alert me to say it’s 9 o’clock and start winding down.

One of the big things that I did, which has made a huge material difference, is as soon the Phillips Hue light
ing came out where you could change all the bulbs and control them from your phone. I put timers on them. Back to the whole ‘don’t have blue light at night thing’, I put timers on them and I basically set the entire house and the whole thing dims from normal lightening and deep submarine red lightening.

It feels like I’m in the Hunt for Red October movie. Feels like I’m in a submarine. But the whole house dims to basically 10% deep red by 9 o’clock. So really it’s fantastic and it sends this signal.

[Damien Blenkinsopp]: I bought some Amazon lights and I was doing that myself at one point but depending on my location it hasn’t been convenient. But have it set up at your homeand automatic, that’s really amazing. If it’s done automatically it’s going to happen.

[Troy Angrignon]: For a while I was doing it manually. I would turn certain lights off or I would do various things. Again, back to the overhead, I don’t want to think about this. I have enough going on in my life. We all do.

[Damien Blenkinsopp]: Well right because you say you were re-organizing your work. I would just be interested to know, you’re basically talking about stress loads here. For me I’ve been subscribing to the fact that if you have too many things in your head, we’re talking about adding things in terms of I’ve got to track this, I’ve got to track that.

That’s not going to be an easy way forward for us because it’s just too much. We already have too many items based in our heads. I don’t know if you did this for your work, but for my work I’ve been hiring a lot more people and systematizing a lot of stuff and basically knocking things off my table.

So just, even if I’m still working the 40, 50, 60 hours, at least I’m only working on four things. And I find that helps tremendously with sleep and just general stress levels. I don’t know if you’ve seen something similar.

[Troy Angrignon]: It does. I think you’ve nailed it and I think that this is all very self-reinforcing and everything is connected to everything. So your sleep supports your work and your work impacts your sleep. And this we could talk for days on this subject. So I think there are basic things that I did.

[Damien Blenkinsopp]: So it’s hard to actually see the quantitative impact in your sleep I guess. I don’t know if you were able to see that. Well you just feel better. You were able to see more hours slept or were there anything that you were able to see that and changed?

[Troy Angrignon]: No, absolutely. I went from two hours to near panic attack sleep to eight, nine hours of solid sleep and it took probably a year to make that change.

[Damien Blenkinsopp]: That’s something I didn’t have as serious as you. I was waking up at 4 o’clock in the morning and I there was nothing I could do about it. I would go to bed at 12 and I would wake up at 4 every day. I’d start working in the dark.

Luckily, I lived in Mexico at the time so I was looking out at the light, the sunrise on the beach and it was amazing. But my girlfriend wasn’t a huge fan of me waking her up at 4 o’clock in the morning when I left. So for me gradually the hours increased.

I think this is kind of funny; I was tracking it for a long time then I stopped tracking and I knew it was fixed because I wasn’t concerned about it anymore because now I’m sleeping seven or eight or nine hours consistently and it doesn’t feel like a problem for me anymore and so I haven’t tracked it for maybe six months.

[Troy Angrignon]: And that’s a really good point. You had an issue amongst all the other issues that you were working on and then when you got to a point where this isn’t really a problem anymore. I don’t need the extra overhead and headache of waking up, finding my phone, clicking this button, doing these things, tracking these numbers. You don’t care at that point. You’re not working on it anymore.

And that’s why it’s kind of like peeling the onion. Pick the one biggest thing, the one biggest boulder and pick one thing that you can do about it and start there.
[Damien Blenkinsopp]: And it’s not necessarily going to be the same thing that you’re going to be doing for the next year. Maybe you’ll work on it for three months, you’ll fix it and then you will say, what’s next. Hopefully you don’t have to buy a new device, depending on your budget.

Let’s talk quickly about budget, actually. I’m guessing the Garmin’s are some of the more expensive ones. I haven’t looked at the prices myself, but what do you think of the pricing at the moment? For the things I’m buying it’s relatively accessible, I think. They’re around $100 or $150, tops.

[Troy Angrignon]: There’s such a huge range. Before we jump to there, I’ll come right back. But before we leave the sleep subject, just so we can wrap up on the devices. There are a lot of devices ultimately after you get through figuring out what you want to do and fix, there are a bunch of devices as you know that will help you track sleep.

It could be as simple as a sleep cycle on your phone. I’m not a fan of that unless you put your phone on the Airplane Mode because you’ve got this EMF blasting a hundred meters of Wi-Fi right beside you.

[Damien Blenkinsopp]: Did you trust the data on that, because I used it for a little bit.

[Troy Angrignon]: No I didn’t really think the data was any good because it’s too hard to pick it up from the accelerometer on the phone and it’s sitting there beside you. It seems like a bit of a dorky way to do it. But again, if it’s better than it was yesterday, it’s consistently probably inaccurate, back to our beginning conversation.

[Damien Blenkinsopp]: I think that app is a couple of dollars, or is it free?

[Troy Angrignon]: Exactly, it’s a cheap way to get your toes in the water. And then going up a step from there, you could look at some of these low end, Fitbit or equivalent things that kind of clip on. Withings had one which was really dorky.

You’d have to find the sleeve and stick this thing in the sleeve and put the sleeve on and the sleeve would fall off. It was ridiculous. It was unsustainable. So I think anything that’s just really easy that you can put on and hopefully have to push one button and hopefully you don’t even have to push that button in the morning.

That’s a better case. The best case is you’re always wearing it and it just automatically knows you’ve gone to bed and it automatically knows you’ve gotten up. So, if and when you go to check the data, the data is already there and you didn’t think about it.

[Damien Blenkinsopp]: So after you looked at the Beddit and there’s a Phillips one as well. Or they’ve basically have got things placed on the mattress?

[Troy Angrignon]: The Beddit comes in multiple versions. The Beddit V1 came in two versions- consumer and pro, it was Bluetooth legacy, so it was a huge headache. So the process, very briefly was, go find your phone, turn on the phone, open it up, open the app, connect to the sensor, sit there and wait for it to connect to the sensor. Eventually it would connect and you would select the sensor.

Then you would open the app and you would go through these questions. I wanted to throw my phone out the window I was so stressed trying to go to bed every night. And I hated it and everybody I know who used it, stopped using it.

And Dave Asprey was always saying, ‘oh, I love my Beddit.’ And I couldn’t figure out why so I went and talked to Lasse Holstrum who is the founder and he said, ‘oh he’s got the pro version.’ Apparently they went to Bluetooth, BLE, Bluetooth Low Energy and cleaned that all up so it automatically connects to the sensor. So literally all you do is open the app, it auto-connects and you just say, ‘hey, I’m going to bed.’

[Damien Blenkinsopp]: So just to clarify, is that Bluetooth running all night?

[Troy Angrignon]: It is and that’s Bluetooth Low Energy and the transmitters are hanging off the edge of your bed, but there’s a great podcast that Ben Greenfield did about this one as well recently too. These things are not labeled or marked and for folks that really EMF wary, which I’m becoming more so these days, I’m not a huge fan of that frankly.

I haven’t used the Version 2, which is the one they did in partnership with Misfit. What I heard from the founder they were doing the right things for V2. Ultimately I tossed it in the box and got rid of it. I’ve tried the S-Plus by ResMed, which bought some of the IP from CO and it’s actually downstream from Phillips. I think it’s tied into Phillips Corp.

It’s this contact list that sits there at the edge of your bed and bounces these 10 G HZ signals off of your body and it uses echo location to try and figure out your chest respirations from your chest. I didn’t trust that data at all. They say the gut research data that says it’ as good as a 3D accelerometer, which is not saying much.

[Damien Blenkinsopp]: But what you said about it bouncing waves, so it’s bouncing waves of you all night?

[Troy Angrignon]: Yes. It’s basically just sitting there blasting EMF at you all night long, which seems like a bad idea.

[Damien Blenkinsopp]: That seems like a really bad [idea] especially for sleep. If you want to have good sleep, I’m not sure that’s the best idea.

[Troy Angrignon]: In my building I have 20 visible Wi-Fi access blasting out full-bore 100 meter, 2.4 G so I’m swamped in here anyway. So I wasn’t keen on it, sent that one back and then Withings go so slammed by people who hated their product that their CEO actually apologized for how terrible the product was so I don’t think there’s much there.

Then InFIT is one I saw at CES and it looks interesting. It’s a very heavy strip which sits underneath, not on top of top mattress but in between the top and the second mattress. It scans you through the bed. Again it’s doing some kind of signal through the bed.

This is a problem. Everything swarm you in EMF and pulls this data and broadcast from you and I think we’re going to be paying the price on that one at some point, but I’m not sure.

[Damien Blenkinsopp]: There don’t seem to be many manufacturers who are concerned about that though.

[Troy Angrignon]: They’re too busy in the hay day of wearables.

[Damien Blenkinsopp]: I guess we’re ahead of the curve thinking about EMF. Most people aren’t concerned about EMF. Most people you talk to don’t even realize there’s a problem. Although there’s some books which I appreciate like 4-Hour Body by Tim Ferriss.

He talks about the phone waves and keeping them away from your balls. But it’s little things like that. Ever since I read that, that’s a rule I’ve had. I’ve had my phones switched off for most of the time. We don’t know where it’s going.

That’s why there are all these devices out there and a lot of them have these and it’s the one thing that makes me resistant to play with all of the devices.

[Troy Angrignon]: Yes, because it’s an overload.

[Damien Blenkinsopp]: Yes. Maybe in ten years this is going to be something that I wish I hadn’t pursued so intensely.
[Troy Angrignon]: When you’re growing a third arm out of your forehead and you say how did that happen? I think to wrap this thing up on devices; there are a few different things that I would say, easy, lightweight, relatively inexpensive.

I would look at the Fitbits. It’s not deep data but its ok. I would look at the Jawbone Up24 or the Jawbone Up3, which is the new one coming out in month or two. And I think that those are reasonably good. I think the Jawbone actually does now and will have better sleep tracking with more data in it, if you’re more nerdy. That could be an interesting one.

That’s for now. Then actually I think the coolest thing I’ve seen in the sleep space and I’m actually using their program right now is a little thing called Sleepio., which is a sleep coaching tool. Sleepio.com and they’re in the UK.

And I can’t believe how well-done it is. Essentially you’ll get this little animated, British professor who walks you through the complexities of sleep and what your specific issues are. They’ve got incredibly deep, rich branching logic in behind this thing.

If you say my biggest goal is this and my biggest fear is that and my biggest issue is whatever, then that builds the curriculum from there and every week it pulls in your Fitbit or your Jawbone data and then it reviews it with you and says here’s what we learned. Here’s what we were working on. Here’s what you’re going to work on next week.

It walks you through it and ask you, ‘I will make a commitment to you that I will only give you advice based on these 30 years of scientific research and you need to commit that you will do your best to stick to this program because change is hard and changing sleep habits is hard.’ I thought that was a really interesting addition so it’s not a wearable device but it works with wearable devices.

[Damien Blenkinsopp]: That’s more intelligence side and definitely we need to see more of that. What do you think is going to happen over the next five or ten years because that seems like one of the endpoints where you have near artificial intelligence walking you through step by step and fixing your problems for you?

[Troy Angrignon]: I think that’s an early indicator of the direction that we’re going. The stuff that you and I have had to go through just to figure out a) figure out what we were asking and b) how to collect the data c) how to make sense of it or rationalize it or normalize it.

That was really hard for us because we started so early and d) what does it mean? When you look at it on charts and graphs, ‘well am I learning anything or not.’ How many thousands of hours have you spent looking at graphs thinking ‘I have no idea what that is.’

[Damien Blenkinsopp]: I have. You can Google a presentation of me showing people. It’s ridiculous.

[Troy Angrignon]: I actually had people call me on that. ‘That’s a pretty graph, what does it mean?’ It’s been a lot of work for us to figure that out and yet ultimately I have gotten to a point where I’ve been able to say, ‘I know what data means. I know what this is telling me. I know what these trends and patterns are. I can compare this to my goals and I can see I’m either moving towards or away from my goals.

That was a lot of work. That’s why I was so impressed with Sleepio, that they would come right out up front and say, ‘You’re not alone. A lot of people have these sleep problems. It’s also hard so get ready to dig in and do the work and we’re going to walk you through it.

It’s not artificial intelligence but it’s really well-done branching logic.

[Damien Blenkinsopp]: It’s pretty amazing it’s done that. As you said a lot of their hacks, hacks to fix sleep, hacks to improve different things. They’re just kind of still appearing and we’re just getting to the grips of the science and a lot of things.

This is why we have this show. We can focus on data or the data behind things so that we are acting and making decisions that are good versus we don’t know. It’s just opinion. We see a lot of opinion out there when it comes to fitness, health and all of these areas.

I think that’s part of the challenge with that. Before we can get there we need to accumulate a lot of data and people really need to know for sure that when you do this it equals this. But it sounds like they’ve got a really good job. Do you know where they got the actions, basically the things that they’re recommending from?

[Troy Angrignon]: No. I was going to dig into it and I thought actually that I would try a week or two and just walk through their process to see how that’s handled and I’m so impressed that now at this point I have to go back and dig into what their evidence is. What’s their ‘peer reviewing’ research.

[Damien Blenkinsopp]: Excellent. While I’m in London I might reach out to them Thanks for bringing it up.

[Troy Angrignon]: Actually I would definitely do it. They would be worth having on the show I think. And I think to answer your question, ‘where do we go?’ I had this really interesting conversation with a friend of mine, a colleague from my old industry which is Business Intelligence as well as some military intelligence analyst.

I said it seems like we’ve already seen this movie. We already know how to get from data to actionable intelligence, to smart guidance. To say given you’re trying to do ‘x’ the data says you should do ‘y’. And we already know what that data supply chain looks like.

Like how you get the data, clean the data, analyze the data, run it through some kind of mental model or framework and then that outputs this answer which says you should do ‘x’. Then you do ‘x’ and you run through the whole process again. And you say did that work or not. Where we are, we are just really immature.

We’re way back at step one where we’re collecting a huge pile of data and we’re providing some pretty charts and graphs. They’re not that useful and we’re providing a chart or graph, or five charts or graphs for one sensor.

What you really want is this nice, blended, normalized view of all of your data on one time base where you can just look at it and see, almost like those old biorhythm charts, if you remember those things. It’s like your mood is doing this and your sleep is doing that and you’re food intake is doing something else and your workload from your training is doing something else.

You can see the patterns and do eyeball correlation, like when I sleep really short my productivity really sucks the next day or my mood sucks the next day. We’re early in that process I think so we’re going to go through maturation.

I’m giving a talk on this IOT World, I think here in San Francisco soon. What I’m hoping is we can take those lessons from the other industries and instead of taking 30 years to get to the point where we can take data and turn it into actionable intelligence, maybe we can compress that to ten. I don’t know.

[Damien Blenkinsopp]: You’re absolutely right. It’s already being done so well. When I think about my corporate training, it was all analytics was being the big thing for a while. When I was in management consulting and strategy consulting, a big thing with that when you’re trying to roll it out was the KPI, the Key Performance Indicator.

It is one number which you’re trying to bundle a whole bunch of stuff into and then you had to balance the scorecards. You might have heard of those. Those are another nice way to look at data and make it more useful. So you’re right. It’s just about playing with all of these models that we already have. So much work and literally a decade has been spent on those things.

[Troy Angrignon]: I think we know that stuff. We just need to bring it across and import it from those other industries and hopefully we can do that and not take the same 30 years.

[Damien Blenkinsopp]: At some point. Where should someone look to learn more because you’ve got all of these great charts on your blog? So if someone wants to see the map of the whole wearables devices in 2015, those charts are awesome. Where do they go to get those?

[Troy Angrignon]: I don’t have a short URL for that. I’ll just give you the website and I’ll spell it out for everybody since it is a French complicated name. But its www.troyangrignon.com, that’s my full name, Troy Angrignon. There’s a Wearable section, Health and Fitness section, Market Map section and they are just different views into all of the different blog posts. I would say that’s probably the best place to go. Everything I write and all of my speaking that I do is always posted there as well.

[Damien Blenkinsopp]: We’ll put direct links to all of the charts and stuff and show notes as well as well so the people can find it.

[Troy Angrignon]: Oh yeah, that’s fine too, very good. That’s a great idea. Perfect.

[Damien Blenkinsopp]: I thought it was a French name.

[Troy Angrignon]: I can only swear in French.

[Damien Blenkinsopp]: Do you speak any French? So, besides yourself, are there other people you look to and you learn from in this whole wearable tech area, which are on top of it?

[Troy Angrignon]: Ray at DC Rainmaker. Anybody who has ever done any sports and used any sport device owes Ray a huge debt of gratitude. He has a site called dcrainmaker.com. You looked at my charts and we were laughing.

I said I felt like Russell Crow from Beautiful Minds sitting there in my garage connecting things with strings because everyone looks at this and asks is that in your brain? He’s even more extreme. He will do these reviews that are longer and better than any other review on the planet, but he will preface it by saying, ‘This is just a brief look. I will do my full review later.’

It just makes me laugh. And his real reviews are 30 pages deep of every screen and unboxing and it’s just insanely deep. So I have learned a ton from Ray. I owe him a huge debt of gratitude for getting me up to speed over the last couple of years. I would say he is the leader.

He knows so much about the industry. He gives great presentations at the ANT+ forum each year. You can often Google those and find those presentations. I get a kick out of them because he always starts with his first slide, ‘Why should you listen to me?’

And it says my site is now responsible for $900 million of purchasing decisions and he is not making it up. This isn’t even his day job. This is his side thing he does for fun. I would definitely point at him. The bio hacking stuff, you and I are already pretty big fans of folks like Ben Greenfield or Dave Asprey, lots of folks in there and their camp. Those are probably the biggest ones that I can think of.

[Damien Blenkinsopp]: Great. Thanks very much. Now for you; what are you focused on in terms of data metrics for your own life along routine basis? Maybe you’re doing a lot of projects at the moment but are there other things that you track on a routine basis and pay attention to?

[Troy Angrignon]: Aside from wearing four devices all of the time and cross referencing them, so the data I’m looking for is how good is the data. That’s a different thing. Personally, the things I track day to day are my sleep so I can go visit my little British Sleep Prof over at Sleepio and he can berate me for how little sleep I’m getting and my daily workouts. I throw a heart rate strap on and I put my Garmin 920xt on, which I love. I go do my workouts. I come back in and save it and it uploads and all of that stuff goes into Garmin.

[Damien Blenkinsopp]: Which actual markers do you look at? Do you scan them all or are there ones you pay attention to more? Do you look at HRV for instance?

[Troy Angrignon]: Yes. HRV, Heart rate variability, which we’re not going to go into here obviously, but it’s an indicator of how over-trained you are. I think my biggest ones are really sleep, activity level through my workouts and recovery level. The HRV and I use something called Rest Wise at Restwise.com.

I use Rest Wise, HRV, morning heart rate, muscle soreness and just my own intuition to assess how I am feeling. Am I over training? Do I need to back off or not? To me this has been a really big issue, which is ‘we can see the trees, we can’t see the forest’. Ultimately at the end of the day, I want to train as hard as I can; going up the curve towards some events I have planned.

But I also don’t want to over train and then incur risk of injury. I think we talked a lot about that in our one to one call. I think for me its sleep, recovery, nutrition, training load and stress load, which is an ambient awareness of it.

[Damien Blenkinsopp]: I guess with the sleep is what we were talking about. You just keep an eye on it and the number of hours you’ve slept.

[Troy Angrignon]: That’s a really interesting thing. I used to be very focused on deep and life and one of the pieces of education I got from Sleepio, is they’ve said, ‘we done this 30 years. We’ve realized that the phases inside don’t matter, which was a bit of a surprise to me, frankly.

What really matters is of the ‘x’ hours you spend in bed, what percentage of that time were you asleep. The phases inside that really aren’t material.’ Now I think that that’s a different case if you’re self-medicating yourself to sleep and you’re not getting the phases.

I’m just using Fitbit and Sleepio. It’s giving me a record and it’s giving me an efficiency score and that efficiency score is pretty low. It’s 65%. So I am spending 30-35% of my sleep rolling around.

[Damien Blenkinsopp]: I don’t remember my numbers. With the Basis mine were lower but I don’t know about these devices. That might be average for that device, right?

[Troy Angrignon]: It’s definitely nice having both the accelerometer and the heart rate in there to cross reference that data to get the slightly more accurate sleep analysis.

[Damien Blenkinsopp]: Thank you so much for your time today, Troy. Final Question; what would be your number one recommendation to someone who is trying to use some form of data to make their lives better, basically decisions on their body’s health performance and longevity?

[Troy Angrignon]: I think the number one is really just to know what you’re trying to do first. We talked about it in this call. What is the one thing that would make a real difference to you and what is the one goal you have set there? Is it your sleep or it doesn’t matter? Pick one.

Pick that one thing and do one thing in that arena and track one thing that’s material. That makes a difference. For sleep you want to just track number of hours and percent of time you’re in bed actually asleep. That’s huge. Have a goal and then track something that’s material that makes sense in relation to that goal.

I’ve seen too many people tracking way too much data that’s not material and that’s not useful and doesn’t lead to change. I had a conversation with somebody who literally tracked every meal for three years but didn’t lose a pound.

And they changed their diet and suddenly started shedding the weight because they got more information. For three weeks of not making a change, it should’ve been what I am doing isn’t working. I guess maybe that’s the second fall on point to make. Use the number and test the metric. If it’s not showing up try something new.

[Damien Blenkinsopp]: Absolutely. Keep it simple.

[Troy Angrignon]: And if the change you’re looking for is not happening, you’re probably not changing.

[Damien Blenkinsopp]: You have to give it a little bit of time, a week, two weeks, depending on what that is. And adjust for sure. Well Troy, thank you so much for your time. This has been a great discussion. We’ve pretty much looked at the whole landscape today. Thank you so much for your time.

[Troy Angrignon]: Damien, it’s been great.

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Is Heart Rate Variability the best biomarker of the time to track our longevity? In this episode we look at why HRV may be the best way to track how well you are aging and the bets being placed on it in Silicon Valley to drive innovation in anti-aging and longevity research.

Previously we’ve looked at using HRV for training and recovery, stress management, and tracking hormesis. If you are new to biohacking, HRV is an easy economical way to start tracking. All one needs is a heart rate strap and phone app.

The activity around HRV in Silicon Valley originates from The Palo Alto Longevity Prize – a one million dollar life science competition to “hack the code” that regulates our health and lifespan. The prize is using HRV as a proxy measurement for longevity, so teams will compete against each other to find tools and tactics to increase the HRV metric – and thereby potential longevity.

“Whenever you want to nurture innovation, you need to have metrics… The reason HRV was chosen was… one, we have decades worth of heart rate variability data…. there is good cohort data, population level data, that suggests that declining HRV is also due to a chronologic age…. [and] unlike most biomarkers in health, HRV can be measured continuously, contextually. You can measure it for 24 hours.”

– Dr. Joon Yun

Today’s interview is with the man behind the Palo Alto Longevity Prize, Dr. Joon Yun. Dr. Yun is managing partner and president of Palo Alto Investors,LLC, which oversees 1.8 billion dollars in assets invested in healthcare. Dr. Joon Yun is board certified in Radiology, was clinically trained at Stanford and received his M. D. from Duke Medical School. He has published numerous scientific articles, and has a column in Forbes magazine. Recently, he agreed to sponsor the Palo Alto Longevity Prize by donating 1 million dollars to this life-science competition.

The show notes, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

Show Notes

  • By the mid 40’s there are both subjective (able to be felt) examples and objective (not felt) examples of homeostatic capacity loss. (3:46).
  • Prior to middle life, the body’s homeostatic capacity is able to return to baseline (5:00).
  • Aging can be thought of as a decline in the body’s ability to get back to homeostasis due to an erosion of homeostatic capacity (5:27).
  • The healthcare system is centered on returning homeostasis and not homeostatic capacity (5:41).
  • The goal of the Palo Alto Prize is target and nurture ways to improve and restore homeostatic capacity, instead of restoring homeostasis (6:10).
  • There is some overlap in hormesis and homeostatic capacity (9:20).
  • Challenges to the body can increase homeostatic capacity (9:53).
  • The final perimeters of the Palo Alto Prize were announced at the end of 2014 (10:29).
  • Millions of people succumb to aging or aging-related issues. Thus, the sooner we start, the more people can benefit (11:19).
  • This is the first prize Dr. Joon Yun has sponsored (12:09).
  • Despite the innumerable traits of homeostatic capacity happening on the physiological level, there are existing biomarkers that represent proxies of homeostatic capacity (12:51).
  • Practical reason for why HRV was chosen as a biomarker include: (1) ability to be measured continuously (this is a unique feature compared to other health biomarkers); (2) ability to be measured contextually; and (3) ability to be measured non-invasively. Globally, there are numerous devices available to help measure HRV, thus providing an opportunity for a range of teams to apply for the prize (15:34).
  • Orthostatic hypotension was another biomarker considered (16:50).
  • Too rapid heart rate response or insufficient heart rate response during cardiac stress testing may indicate dysfunction in certain areas (18:05).
  • The data from orthostatic hypotension, cardiac stress testing, and heart rate decline after exercise are strong relative to other areas of homeostatic capacity assessment (19:05).
  • The goal of the project is to gather more data and develop more biomarkers of homeostatic capacity (19:14).
  • The definition (or standard) of HRV to be used in awarding the Palo Alto Prize will be determined by a team of experts (19:45).
  • Dr. Joon Yun does not track biomarkers on a routine basis (20:51).
  • Dr. Joon Yun’s single most important recommendation is exercise to improve your health, longevity and performance (23:37).

Thank Dr. Joon Yun on Twitter for this interview.
Click Here to let him know you enjoyed the show!

Dr. Joon Yun

The Tracking


  • Heart Rate Variability (HRV): measurement of how one’s heart rate varies over time. Dr. Joon Yun describes HRV as a proxy for autonomic capacity, which itself is a surrogate of overall homeostatic capacity. Additionally, HRV can be taken continuously and non-invasively. Please check out other episodes for details on how to track HRV and optimum ranges.
  • Orthostatic Hypotension: measures the ability of the body to recalibrate blood pressure when moving from a lying to sitting position or a sitting to standing position. In aging, it has been associatively observed that the body’s ability to adapt to rapid changes in blood pressure deteriorates. Therefore, this is one way to infer homeostatic capacity and is another biomarker considered for the prize.
  • Heart Rate Recovery: measures autonomic capacity by looking at heart rate behavior after exercise. Looking at this decline over a certain time period gives insight into the function of the heart when compared with a normal curve.
  • RMSSD (Root Mean Square of the Successive Differences): the industry standard for measuring and calculating HRV. Discussed in more details in Episode 1 & Episode 6.
  • lnRMSSDx20 (RMSSD with natural log and multiple of 20 applied): applications have begun using this measure. This is RMSSD scaled to an index of 100 for easier use. Discussed in more details in Episode 1 & Episode 6.


  • Homeostatic capacity: a network of traits in our bodies to achieve homeostasis. It is the body’s ability to “self-tune” or, in response to stressors, its capability to self-stabilize. This capacity or trait is inborn: when we are young, the feeling of health feels like “nothing”. Once it begins to decline in midlife, we become aware of it. For instance, we notice an inability to tolerate hot or cold weather or that the recovery from a late night takes longer that it use to. There are also changes not necessarily felt, such as homeostatic capacity returning elevated blood pressure to base levels.

Lab Tests, Devices and Apps

  • Cardiac Stress Test: this test is an assessment of the body’s response to an exercise heart rate challenge. Dr. Joon Yun describes this as a test, common in standard practice, that can be viewed as a “homeostatic capacity test”.

Other People, Books & Resources


  • Edward J. Calabrese Ph.D.: Dr. Joon Yun first heard about the idea of hormesis from him.
  • Aubrey de Grey: a link to Aubrey de Grey’s published work. He was also mentioned in this episode by Dr. Joon Yun in reference to the Methuselah prize. We talked to Aubrey de Grey about his framework to increase longevity in Episode 14.


  • Methuselah Mouse Prize (MPrize): started in 2003, this prize was designed to accelerate the development of life extension therapies. In 2009, the MPrize for both longevity and rejuvenation were awarded. Currently, $1.4 million is available for awarding to researchers who can top previous winners’ performances.

Full Interview Transcript

Transcript - Click Here to Read
[Damien Blenkinsopp]: Yeah, it’s great to have you here.

So, you’re involved in this big project called the Palo Alto Longevity Prize. Could you give us a run down. What is the vision behind that, and why have you put this together now?

[Dr. Joon Yun]: The vision of the Palo Alto Prize is to nurture innovation that improves the homeostatic capacity as a gateway into promoting healthy longevity, and health span.

[Damien Blenkinsopp]: Right, so, I think a lot of people aren’t exactly sure what homeostatic capacity is. So how would you describe that, and why is it particularly this homeostatic capacity that you’re linking to longevity?

[Dr. Joon Yun]: Most people are familiar with the word homeostasis. So think of homeostatic capacity as a network of traits in our body that enable us to achieve homeostasis.

Now homeostatic capacity is something that’s endowed by nature. It’s been shaped by evolution. And you can think about it as robustness, resilience, coping mechanism, dynamic range, anti-fragility. These are all kind of similar concepts. But the basic notion is that we have an incredible set of traits that enables our bodies to self tune.

One of the ironic things about homeostatic capacity is that we don’t really realize we have it until we start losing it, typically in mid-life, where all the sudden you start to feel things that you didn’t feel before. At nighttime, it’s a little too dark, the sun shines a little too bright during the day. [When] riding a roller coaster, you may come out of it nauseous, because your body doesn’t re-calibrate. Altitude sickness starts emerging around then. The bouncing back from injury or jet lag, or a late night.

All these things are suggestive ways that we start to experience the loss of something that we didn’t have. That we didn’t used to feel. The loss of something that we didn’t feel when we were younger.

In fact, when we’re 12 years old, another way to define health is the feeling of nothing. When we’re young and we’re healthy, what we feel is nothing. It’s when we start feeling something that we realize something’s going on.

[Damien Blenkinsopp]: Right, right. So in a sense, this is balance, and you’re just feeling well without any negative symptoms, or negative feelings, I guess.

[Dr. Joon Yun]: Yes. So you can think about homeostatic capacity as your body’s ability to self tune, and get back into balance or homeostasis. But think about all the things that happen…well.

So we’ve described the things that are subjective that you can experience. There’s also a lot of objective things that you can’t feel, but start to emerge by the middle of life, again that’s defined by the mid-forties.

When we’re young and our blood pressure’s high, or our blood sugar is high, the body has the homeostatic capacity to return those numbers to a normal baseline. But as we age, a lot of those numbers no longer return to baseline. They remain high.

And we call those situations diseases like hyper-tension and diabetes. The thing about a lot of the diseases of aging as reflections of the body’s declining intrinsic ability to get back to homeostasis because of potential underlying and inevitable erosion of homeostatic capacity.

Now what we do in the health care system today, we provide an external mechanism called the health care system, we trying now here in the US to help the body get back to homeostasis. But because we’re trying to restore homeostasis, and not necessarily focused on restoring homeostatic capacity, the inevitable loss of homeostatic capacity continues manifesting in increasing features of aging. And in the long run the health care system can no longer help the person make the homeostasis, and then death ensues.

So the gambit of the prize is to target and nurture innovations that improve homeostatic capacity. That we restore homeostatic capacity instead of restoring homeostasis, to see if this could be a gateway into improving health, and sustain health, and longevity could be an outcome of that.

[Damien Blenkinsopp]: Great. So this is an area you feel is undervalued, under-utilized, and currently when it comes to health and health care, and it’s something you want to promote.

What is the kind of vision behind the prize? For instance, we had an interview with Aubrey de Grey recently, and he’s talking about extending lifespan considerably. Would you put it along those kind of lines, or is it more kind of making sure that we live to our prime years 80 years old, 90 years old, 100 years and we live really well, versus having the current diseases which plague a lot of people these days?

[Dr. Joon Yun]: Well it’s really about promoting health. Longevity might be an outcome, but there’s a difference between something being an outcome and a goal.

Our goal is to improve health, and helping longevity may be a consequence of that. So I do think that the target is a little it different. And I also think that the target, the homeostatic capacity, is different than homeostasis.

To give you the example of high blood pressure. Think about high blood pressure or hyper-tension as it’s called medically as the lab error reported by the body of the blood pressure being too high. And the way we fix this is in the modern medical system is we give patients drugs that normalize that blood pressure. Meaning, return it back to a number associated with homeostasis.

But because we are externally providing that capacity, when you miss your dose of drug, or when you come off a drug, in many cases your baseline has progressed, and may be even worse. Because the one thing your body knows how to do is to homeostasis against all the external challenges. The more it sees blood pressure lowering drugs, in many ways the body rebounds. It’s called toxic phalasis.

And this is a challenge with most pharmaceuticals that the body remodels against the drug. So when you come off the drug, your lag error can even be worse. You can have rebound hyper-tension, something called addiction decompensation.

The way nature addresses high blood pressure is by exercising. Meaning the natural way to treat hyper-tension is to leverage your homeostatic capacity as a way to lower your blood pressure. Meaning, when we exercise, we’re actually increasing our blood pressure by challenging it. And in this sense, the homeostatic capacity can be stronger. And so the baseline blood pressure actually gets lower the more times you raise it. So it’s almost a mirror image of what we’re doing with the medical system today.

And when we think about the diffuse benefits of aging in, really, all those views of aging, including longevity itself, it’s generally suggested that using homeostatic capacity as a treatment for aging, rather than tools of homeostasis, may actually work in terms of expanding health for society and expanding longevity.

[Damien Blenkinsopp]: Great, great. Thanks. We’ve spoken about hormesis quite a few times on the podcast before. Would you say it’s related to hormesis? When you were talking about exercise, it sounded very similar to the kind of hormetic discussions we’ve spoken about. So are homeostasis and hormesis linked?

[Dr. Joon Yun]: Some people may find some overlapping ideas. Hormesis I first learned of it through some some great body by Ed Calabrese, out in the East Coast. My understanding of it is that it’s the notion that at different ends of the curve your going to have differences in response.

I guess there’s some relation to it, although I think the mechanism attributed to hormesis has been debated out there. But the notion that challenges to the body that, many challenges to the body can actually paradoxically induce competitory strength, or induction of homeostatic capacity. But I do think that there’s some overlap in the ideas.

[Damien Blenkinsopp]: Great, great. Thanks for that. Helps to situate our audience better.

Okay, so coming back to the Palo Alto Longevity Prize. Is there a specific reason why you decided to do it this year, and could you explain a bit more about the background? So you already have many teams participating in this challenge. Have they got any rules around defining the participation? So, have you said that there’s any restrictions to what they can do in order to compete? Or is it kind of very, very broad?

[Dr. Joon Yun]: The Palo Alto Longevity Prize is run by a team, including some of the scientific experts and industry experts in health care, and they’re the ones who convened to determine both the criteria, and they’ll represent the independent judging panel as well. And those final parameters will be announced to the public sometime this year. And there they’re accepting public comments.

Remember this is a new area, homeostatic capacity. It’s kind of a new word, although I think it is a phrase the scientific community understands, and it can embrace, and can develop innovations around. So we’re in the early stages of all that.

As to why do it this year? Well, we know that every year we wait, there’s enormous amounts of suffering that goes on around the planet associated with age and loss of life. And so we know that every week we wait, a million people have succumbed to aging or aging associated conditions. So, we think this is a very significant time, and the sooner we start, the better.

We do think that this is going to take some time, and maybe a series of prizes, with a lot of different starts. And we think it will be a long journey, but the earlier we start, the more people can benefit from improved health.

[Damien Blenkinsopp]: Great, thank you very much. I understand that you’ve put your money, or is it Palo Alto Investors that have put the money in for the prize to stimulate? We’re seeing a lot more prizes now, as a method for stimulating innovation in other industries. I think this is the first one that’s tried to do it in health care, and certainly longevity. Or have you seen other ones before?

[Dr. Joon Yun]: I think there have been other prizes before. The [inaudible 11:56] Prize, Aubrey de Grey, the Methuselah Prize. I’m new to prizes. I’m the sponsor of the prize, and I learned about prizes with some of the experts in the prize community.

And one of the things I like about it is that it mirrors how evolution works, Darwinian evolution works. There’s a niche, there’s a diversity of options that compete for the niche, and there’s a winner.

[Damien Blenkinsopp]: Great. Coming back to the rules of the prize, you’ve decided to focus the prize on using heart rate variability, HRV, which we’ve covered quite often in this podcast before. Why did you decide that this was the biomarker you were going to use for the focus of the prize?

[Dr. Joon Yun]: Exactly. So whenever you want to nurture innovation, you need to have metrics. And homeostatic capacity is a new phrase, and there are some existing biomarkers or diagnostic tests that could represent proxies of homeostatic capacity.

But homeostatic capacity is a diffuse network of many, many innumerable traits. Such as physiological level, tissue level, systems level, molecular level, cellular level. It’s a composition and the inter-relationship between all of them. It’s a composite that reflects an overall organismic homeostatic capacity. So the challenge is how do you take and define biomarkers that represent copies that affect the surrogates for homeostatic capacity?

The reason HRV was chosen was, first of all, it represent a… Well, so HRV is heart rate variability. It is a biomarker of autonomic capacity, which itself is a surrogate of overall homeostatic capacity. So it’s just one variable that happens to have a number of features that make it interesting.

Number one, we have decades worth of heart rate variability data. It’s been in clinical use since 1963 to monitor fetal stress. And when HRV goes low, it’s one of the criteria for determining fetal stress and associated infant-fetal mortality. So it’s notable that it’s not used in the post-natal life, adulthood. I mean there are very few labs around the world that actually monitor HRV in patients as they get older.

And there is good cohort data, population level data, that suggests that declining HRV is also due to a chronologic age. And many of the diseases of aging are also associated with aberration in heart rate variability. None of this is established in a causal way, but the degree of association of HRV decline with some features of aging suggest that it might be an interesting biomarker.

But there’s some additional practical reasons why HRV was chosen. Unlike most biomarkers in health, HRV can be measured continuously, contextually. You can measure it for 24 hours. Most biomarkers, as you know, are done through blood tests, body fluid samples. You only get a snap shot in time. And given the dynamism of the system, most biomarkers have a tremendous amount of variation, even in a 24 hour cycle.

So the fact that [with] most biomarkers, it’s impractical to get continuous monitoring, and you can’t detect changing patterns, and changing dynamism over 24 hour life cycle, as well as in a very different context, make it less useful than HRV, which can be measured non-invasively, continuously.

There’s also a global footprint of devices, including consumer devices, that help measure HRV. What that does is opens up the aperture in terms of the breadth of teams that can apply for the prize. If we make the biomarkers too narrow, it limits the number of labs and groups around the world who might have an innovative idea on the intervention side to be able to process their innovation.

So there is a tradeoff between specificity of a biomarker for homeostatic capacity versus this practically of the diversity of options that we may be able to solicit. So, HRV, again, there’s been empirical association with aging. Mechanistically because it’s associated with autonomic capacity it is a feature of homeostatic capacity. It’s global footprint, non-invasive, continuous monitoring, and relatively inexpensive to obtain, unlike some biomarkers that are proprietary, it’s pretty costless.

[Damien Blenkinsopp]: Great, thank you for that. Are there any other biomarkers that you looked at, and you considered for measuring homeostatic capacity?

[Dr. Joon Yun]: Absolutely. There’s only a small subset of modern diagnostic tests that actually assess homeostatic capacity. And you can think of a lot, well, actually get an annual checkup, but indirect proxies. But more direct proxies, more direct surrogates, really require tests themselves be dynamic.

So, an example of another potential surrogate is orthostatic hypo-tension. So it’s your ability of the cardiovascular system to recalibrate blood pressure from a sitting to a standing position, or lying to a sitting position. When we’re young, we have tremendous real time system dynamism that allows us to adjust to quite the rapid demand. And you really don’t have much else raising your blood pressure.

But as we get older, it’s observed that the body’s ability to adapt to those change in conditions deteriorates. So it’s associated with aging, and that’s one way to infer that there’s declining homeostatic capacity. And this may help explain why as you get older there’s one of the contributors to syncope, one of the contributors to declining ability to perform a lot of more strenuous physical tasks.

You can also start to think about the cardiac stress test as an example of a homeostatic capacity test. This is one of the ones that is more standard practice out there for the medicine of today. Essentially, one of the things we’re measuring is the body’s heart rate response to an exercise challenge.

And in some cases the heart rate response is too rapid. So that could reflect some dysfunction in the Diego Connor Response. And in some cases the heart rate increase is insufficient. So, BP is reflective of a system that is less dynamic than it used to be. And these things are associated in a lot of, on toward clinical outcomes in the long haul.

Anything where the heart rate declines after exercise. And one of the things we look for is does the heart rate return to normal, does it look like a normal heart? Does it happen in a normal amount of time? Because as we age and our intrinsically homeostatic capacity declines in which case this is a non-capacity there is abnormal return to normal as well.

So these are small subsets of the overall diagnosis landscape used in clinical medicines today, that we think already reflect homeostatic capacity. But those things require, there’s a higher burden in terms of throughput to asses innovation, and the tests themselves require more involvement.

And furthermore, the data in those areas are strong, although there are many others, but we certainly need more data across the spectrum. So one of the hopes for the competition is that we help promote the idea, that we gather more, and develop more biomarkers for homeostatic capacity.

[Damien Blenkinsopp]: Alright, great. Great, I didn’t realize that was part of the project. Have you defined the exact standard? Because there’s a few different standards of HRV out there.

One of the ones we’ve discussed quite a lot is is the natural log, RMSSD, which is multiplied by 20 and used by a lot of consumer devices at the moment. Have you defined that as yet, or are you going to be defining that at one stage as a criteria for use in the project?

[Dr. Joon Yun]: Yeah, we’re deferring that to a team of experts that have, they did the exact same topic. So, I’ll leave it up to them

[Damien Blenkinsopp]: Great, great. How can people get involved in the Palo Alto Longevity Prize? I understand there’s already 15 teams which have signed up? Maybe there’s a few more already. What’s the timeline before, for instance, you stop accepting new teams, and then for the other steps of the project?

[Dr. Joon Yun]: Yeah, you know, I don’t have that information at my fingertips. Again, all of that, the process is being managed by the production team. And I’m a sponsor of the prize. So for those details I’ll have to refer you to the team.

[Damien Blenkinsopp]: In terms of your own personal use of biomarkers, are there things that you use, or you track on a routine basis for your own health, longevity, or performance?

[Dr. Joon Yun]: You know, I actually haven’t. I haven’t thought about this project relative to my own health yet. It’s something that I probably will consider. But no, I’m not doing any personal tracking right now.

[Damien Blenkinsopp]: Maybe that’s because you’re really healthy and your homeostasis is pretty good, so you know you don’t feel out of sync, and the need to do it.

[Dr. Joon Yun]: Oh no, I definitely feel it. But yeah, these are early days, and I think a lot more science has to happen. And I think, I think we will learn about it, if nothing else, from this process.

[Damien Blenkinsopp]: Great, great. If someone is interested in getting involved in this, perhaps putting together a team, should they just go to the website for the Palo Alto Longevity Prize, or I understand it’s still available for signing up, as a project team. So would that be the best place to go?

[Dr. Joon Yun]: Yeah, I think the best way to engage is to read through the website. And I believe all the details are there, at the paloaltoprize.org. I believe all the teams have signed up through the website process.

[Damien Blenkinsopp]: Do you know if there’s other ways people can participate beyond just putting together a team?

[Dr. Joon Yun]: I don’t know, I don’t know. Again, I will defer that to the team, the way the public can engage.

[Damien Blenkinsopp]: Great, great. What do you think will happen in the next five or ten years in this area? Have you got some kind of vision or hopes, or are there any things that you’re excited about? The opportunities that are going to occur in this area, biomarkers or longevity, in the next five or ten years?

[Dr. Joon Yun]: I do hold out some hope that there’s a small chance that there are some major breakthroughs coming. And you can sense that even in talking with teams. Scientists tend to be pretty conservative, and also for reasons of competitiveness they tend to under-share hypotheses and preliminary data. And after you hear enough of these really intriguing, unique ideas, you realize that the scientific field is more advanced than the public realizes.

And one of those things that prizes are trying to accomplish prizes such as ours and the initiative such as ours is to accelerate those ideas and actions. So it’s possible that there’s some major breakthroughs that are possible in the five year time frame.

The thing that we know for sure, is that we’ll learn a ton, and the idea to create new paths and new avenues of research that give us more shots on goal in terms of improving people’s health.

[Damien Blenkinsopp]: Great, great. Thanks for that. Do you have one biggest recommendation or insight that you’ve used some kind of data, or you’ve learned about your biology when it comes to health, longevity, and performance, that would be a recommendation for other people when they’re using data?

You’ve mentioned a few things as we’ve gone through this talk about why you selected HRV, for instance. And what would be your one biggest recommendation for using data effectively to improve health, longevity, or performance?

[Dr. Joon Yun]: Well, for now I like HRV because it’s affordable, and it’s also accessible from a technology perspective. And I think the access is growing throughout the world. I like the convenience factor. It’s more practical.

Most other biomarkers, I think the distribution isn’t as broad, and the effect is not at real time. And in terms of in lifestyle habits that, in a way that also match to improving someone’s health…. exercise is still my favorite. And there’s good data suggesting exercise improves the measures of HRV.

We also know that our improvement of HRV as well as exercise itself is also with the amelioration of the stages of aging. So, based on what is known today, I think that’s probably the most practical thing that a person can do to enhance their health.

[Damien Blenkinsopp]: Great Joon, yeah. Exercise is very important. Thank you so much for your time today. I really appreciate it, I know you’re a very busy man. We’ll put together some information on the project, some of those references, in the show notes so everyone can get access to that. Is there anything else that you’d like to share about the project that we haven’t covered already?

[Dr. Joon Yun]: No, that’s great Damien. I appreciate your time, and thank you for having me on your show.

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Today we’re looking at HRV- endurance training, adrenal fatigue, and future app developments.

If you didn’t listen to it, in Episode 1 we primarily looked at resistance training, or weight training.

Today we also look at some scenarios where the HRV metric can be confounded where an increase in it is not good, how it can be used to identify possible adrenal fatigue and how to improve its accuracy by combining it with Resting Heart Rate and qualitative measures.

Today’s guest is Simon Wegerif who founded ithlete, the first HRV app company, which appeared 5 years ago in 2009. In comparison to Andrew Flatt, whose focus was resistance training, Simon has a background in primarily endurance training and it was for this he originally became interested in HRV.

Since 2009, through working with its client base including a range of pro and amateur athletes and everyday gym goers, and now universities in connection with studies, ithlete has evolved its app to cater for specific scenarios like adrenal fatigue and understanding how individual factors are impacting training. Simon has been diligent in staying up to date with the research and adapting the ithlete app to take advantage of it as it evolves.

The show notes, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

Show Notes

  • The status of research on Heart Rate Variability and some of the issues to overcome such as standardisation.
  • HRV as a predictor of endurance performance – now as effective as running times?
  • Using “Active Recovery” to recover quicker from endurance and resistance training.
  • True overtraining vs. non-functional overreaching – how to improve training results by understanding how HRV indicates these two .
  • How to diagnose potential adrenal fatigue with a combination of HRV and RHR (resting heart rate) metrics.
  • The one situation where you don’t want your parasympathetic to become dominant (or your HRV to be high).
  • The need for HRV benchmarks to be established in order to compare your “health future” to others and as a proxy for aging.
  • The Palo Alto Prize spurring on new investment in research to improving longevity based on using HRV as a feedback mechanism for experiments.
  • Using yoga breathing (Pranayama) to increase Heart Rate Variability by up to 5 points within a few days.
  • The biomarkers Simon tracks on a routine basis to monitor and improve his health, longevity and performance.
  • Simon’s one biggest recommendation on using body data to improve your health, longevity and performance.

Give some love to Simon on Twitter to thank him for this interview.
Click Here to let him know you enjoyed the show!

The Tracking


  • Heart Rate Variability (HRV): Measures how your heart rate varies over time. Research studies link HRV to recovery status, stress and other aspects of human physiology.
  • Resting Heart Rate (RHR): Measure of your heart rate at rest (typically measured upon waking).
  • Calories: We discussed the merits of measuring calories in and out, the current hype cycle around ‘calorie counting’ apps and devices, and its relationship with weightloss.

Apps and Devices

  • ithlete HRV App: The app Simon developed which includes some of the RHR and adrenal fatigue functionality discussed during this episode.
  • Polar H7 Bluetooth Smart Heart Rate Sensor: A chest strap heart rate sensor that works with the ithlete and other HRV apps (Damien uses this one).

Simon Wegerif and ithlete

  • ithlete: Simon’s company and the HRV app with the same name.
  • You can also connect with Simon on twitter @SimonWegerif.

Other People, Books and Resources



Full Interview Transcript

Transcript - Click Here to Read
[Damien Blenkinsopp]: Hi, Simon. Thank you very much for making time today to come on the show.

[Simon Wegerif]: No problem, Damien. Really good to talk to you.

[Damien Blenkinsopp]: What I thought we would first do is quickly, where does ithlete fit in with the world of HRV apps and development, from your perspective?

[Simon Wegerif]: Okay, well, ithlete was the first HRV app available, and when I first started getting really interested in HRV, which was early 2009, I decided it was so interesting to me as an engineer by background, but also a keen recreational endurance athlete, trying to make the most of my own somewhat limited abilities, that the iPhone was just being launched early in 2009, and talking to a couple of people, I was looking for ways to realize my hopeful invention of a convenient, simple-to-use, but accurate HRV measuring device. And people said, you know, why don’t you do it as an app in the iPhone? So I started thinking about that, and I made that my target during 2009, and got the prototypes all done on an iPod Touch, and at that time, I think it was IOS version 2 was just coming out, so we were easily the first to bring even accurate heart rate measurement onto the iPhone, let alone HRV. So we’ve been doing this for a little while now, and the product, I think the current version of the app is relatively mature because of that.

It’s also — being the first gives you some advantages in the early — doctors in research started looking at it quite early on, and we’ve now got some good quality validation studies that have been done that show, in fact, the ithlete measurement to have an almost perfect correlation with the gold standard of ECG, which we’re very happy about. The ithlete finger sensor has also been validated.

[Damien Blenkinsopp]: Great, great. Well, you have three sensors. You’re using the finger sensor, the Bluetooth heart rate chest straps, and isn’t there another one?

[Simon Wegerif]: Yeah, the other one was actually the original one, Damien, so in the early days of the iPhone, there wasn’t any convenient and reliable way of getting a heart rate signal into the phone, so I designed a little adapter, a plug-in adapter which would go into the headset socket, which I still think was a good choice, because headset sockets are available, you know, on pretty much every phone, and the way they’re connected has remained standard, now, for three or four years. So it’s a little device which users can take from one phone to the next, be that iPhone, Android, or even Windows phones, if we do an app version for that. And that little receiver picks up the signal from the Polar type of chest strap, and, of course, that Polar transmission system has been around since the early 1980s, so there’s an awful lot of products in the market that support that.

In fact, although Bluetooth [Smarties 00:05:56] is, in many ways, the state of the art, and the finger sensor is the most convenient, we still sell a lot of the — what we call the little ECG receivers because of the massive installed base of Polar type straps and systems.

[Damien Blenkinsopp]: Okay, great. So I know you stay up-to-date with the research, and you’ve been following this since 2009 or before, so could you give us a bit of an overview, from your perspective, of the research? How much is there related to HRV? Where are the strongest areas, and, you know, how you look at it?

[Simon Wegerif]: Yeah, I think if you were to put heart rate variability into PubMed, which is the — you know, the recognized research database of peer-reviewed papers, I think you’d probably get about 14,000 hits. So there’s an awful lot of peer-reviewed research which has been done on HRV.

[Damien Blenkinsopp]: Do you mean 14,000 papers, separate papers?

[Simon Wegerif]: Yes, 14,000 separate papers, yeah.

[Damien Blenkinsopp]: Great, great.

[Simon Wegerif]: Which is quite a high volume. A lot of that is focused on disease state, so looking at autonomic dysfunction, for instance, in diabetes, cardiovascular diseases, cancer, and a lot of other disease states like that, but there is a fair body of research studies on sports performance and health as well. During my preparation for designing the ithlete app, I read about 500 papers during 2009, and I’ve now got about 1,000 in the collection, my collection that I’ve read.

Some of the papers have got some strikingly good methodologies and breakthroughs, and others are a bit weaker. I think one of areas where heart rate variability research has not done itself any favors is not standardizing in units or protocols. For instance, things like the duration of the measurement, the units that are going to be used, the position of the subjects, whether they’re lying down, walking around, standing, sitting, what are they doing. There hasn’t been much standardization there, I think partly because a standards document was never adopted in the industry.

[Damien Blenkinsopp]: So one thing I noticed about your ithlete app when I was playing around with it was that when you’re taking the reading, it’s got the breathing timer. It’s got this circle that moves up, in and out, with your breathing, which I thought was great to try and standardize that aspect a bit better in terms of how you’re breathing and just keep more rhythmic and controlled every time you’re doing it, instead of different. Is that why you put it in there, or?

[Simon Wegerif]: Yes. Breathing has a very important impact on heart rate variability, so when we talk about HRV, particularly in sports performance and everyday health use, we nearly always mean parasympathetic HRV, and parasympathetic HRV is primarily dependent on breathing. In fact, the HRV is caused as part of the breathing feedback loop with the brain. So as you breathe in, your heart rate gets faster; as you breathe out, your heart rate gets slower. And it always seemed to me, as an engineer, that unless you’re controlling your breathing in some way, that your HRV measurement process is going to be somewhat unpredictable, if you’re just relying on a breathing pattern which is uncontrolled. So controlling that breathing, but without creating stress, hopefully, in the user is the objective here, because everyone who knows much about HRV will know that stress lowers your HRV. So we don’t want to stress the person during the measurement, but we do want them to have a constant breathing pattern, and hopefully the ithlete breathing pattern is something that’s evolved over three generations of the app now, and we hope that people find it peaceful and relaxing to use.

[Damien Blenkinsopp]: Yeah, it’s kind of like this pulsing heart thing. I found it relaxing, and it’s just nice to have an indicator. Because I’ve used other apps, and, you know, they don’t have that. So every time you’re probably breathing a little bit differently, but you don’t notice it. So I thought it was a nice touch. Thanks for that overview.

So, you’ve done a lot of work in the endurance and aerobic areas. We haven’t looked at that yet on the show, so that’s what I’d like to explore a bit more with you. Any idiosyncrasies or differences compared to weight training, which we’ve looked at quite a lot with Andrew Flatt in the past. How would you say that it differs from weight training in the way HRV relates to endurance?

[Simon Wegerif]: Well, one thing, as a segue or a link from the body of research on HRV, Damien, is that a lot of the studies in the sports performance area have actually been done with endurance sports. So they’ve been done with running, cycling, rowing, cross country skiing, because, of course, Finland and the Nordic area has been one that has done a lot of adoption and research into HRV. So there is — the body of research in endurance sports is strong. It’s also something that I’ve been personally interested in, because one of the reasons I created the app originally was to improve my own performance, originally, in triathlon, but lately in long distance cycling.

And so HRV, interestingly, has been something which is really quite well proven and quite well applied to endurance sports. And one of the things about some of the research that’s come out in the past couple of years has been the very good correlations between changes in HRV and changes in performance. So there have been studies done at the national level on French swimmers where they measured their HRV before doing a weekly 400-meter pool time trial, and they found the correlation was so good between the individual’s change in HRV and their variation in performance on the Thursday time trial, that they said one or the other is good enough here. So if we measure their HRV, they don’t need to do the weekly time trial to assess performance improvement.

And a key researcher in this field also, Martin Buchheit, also found when club runners were training to improve their performance in 10K races, that only the runners that improved their HRV during — I think it was an 8-week training program. Only the ones that improved their HRV, improved their running times. The ones whose HRV didn’t improve, their running times didn’t improve, either.

So there’s been some very clear findings in the endurance area. And I think training guided by HRV is becoming more and more practical for endurance sports as a way of maximizing performance with the training time that’s available, but without risking overtraining.

[Damien Blenkinsopp]: Right, right. I know with respect to endurance, we’ve touched on this a bit with Andrew Flatt, he was talking about basically how he would be doing weight training, and his HRV would go down, but if he did a bit of aerobic as well, he would limit how far his HRV would drop the next day. How do you explain that? What’s going on there?

[Simon Wegerif]: Yeah, there’s been a pretty important study that came out, I think it was late last year from a couple of researchers in the University of Queensland in Australia, and again with Martin Buchheit involved, that built on work done by researcher Stephen Seiler, who’s been looking at the way, for instance, marathon, long distance runners have trained in Kenya for many years. And what he observed there is that they tend to follow a polarized approach to training. So the majority of their volume, say 80% of their training time, is conducted at what appears, to many athletes and coaches, to be really quite moderate paces, fully aerobic work. And in fact precisely defined, it’s a level of aerobic work below the first lactate threshold.

So essentially the lactate level in the blood is close to the athlete’s ordinary baseline. And recovery from that kind of aerobic work, although athletes can do habitually quite high volumes of that, you know, many hours a week, is very quick. And that’s reflected in HRV. But when you go above that threshold, then recovery takes much longer to achieve.

So in Andrew’s case, I think what he’s really enforcing is the fact that aerobic exercise really allows rapid recovery, and the fact that the metabolism is accelerated is helping to process the byproducts from the high intensity sessions and perform, essentially, what we call active recovery. Active recovery actually gets you back to baseline more quickly.

[Damien Blenkinsopp]: Does that reduce the stress, the stimulus to improve your body in any way? We’ve also spoken to, like, Doug McGuff of Body By Science. He talks about inroads, so, you know, one of the things about heavy weight training is you want to create a large enough stimulus to improve strength. So is this in any way — it sounds like it’s reducing, in a way, the stressor. Is that a correct way to look at it? I’m just wondering if that has an impact on how your body tries to compensate.

[Simon Wegerif]: Yeah, it does seem to be having that effect by stimulating the parasympathetic nervous system. And the parasympathetic nervous system is good for reducing inflammation, for rebuilding energy stores, glycogen in the liver, for ensuring that oxidative stress is reduced. And the really useful thing about long slow distance or aerobic training in endurance athletes is that it provides a good level of stimulus for mitochondria to adapt. So one of the things you want as an endurance athlete is an efficient metabolism with lots of mitochondria in the muscles, which are able to process fuels and turn those into energy. And what you also want is a metabolism that’s able to use fats as fuels. You know, your store of fats in any body, even thin people, is many, many thousands of calories, and fat is a very efficient way to store fuel. You know, it’s 9 calories per gram. Whereas, carbohydrate is 4.2 calories per gram, and carbohydrate is usually associated with quite a lot of water retained in the body as well. So if you can use fats as fuels, that’s a big advantage.

If you’re running a marathon, then you’ve only got enough glycogen for about — you’ve probably got about 800 grams. You know, you’ve probably got — your total body store is about 3,000 calories, of which your body will probably only allow you to use a couple of thousand, so your ability to supplement that glycogen fuel with fat stores is something that your body learns to do and learns to adapt to when you spend time training aerobically.

[Damien Blenkinsopp]: Yeah, we discussed this with Jimmy Moore. He’s done a lot of work with other people in keto diets and so on involved with training. So, yeah, it’s good for you to make that connection and bring that up in this context.

Okay, so kind of round off the impact — so you’re saying it helps recovery — it helps accelerate recovery by stimulating the parasympathetic system.

[Simon Wegerif]: That’s right, as well as building — building the cardiovascular system and energy stores and energy system to make you — make you efficient, really, and be able to go for a long time.

[Damien Blenkinsopp]: Are there any cases where we shouldn’t be doing this? If we’re just focused on HRV, it’s like, oh, well, it leads to a higher HRV, so — if we’re always just aiming to increase the HRV, which is part of the discussion I wanted to have today, so should we always be doing that? So if we’re weight training and we can do a little bit of aerobic to increase our HRV, so everyone be doing this?

[Simon Wegerif]: I think everybody should be doing a certain amount of it, but it’s not going to lead to good race pace performance unless it’s also complimented by some high intensity stuff. And the general adaptation syndrome of Selye, which was, you know, written a very long time ago, basically talks about stressing the system and then allowing time for it to recover, and when it recovers, it supercompensates, so the body is stronger than it was before. And high intensity work is a very good way of stressing the body sufficiently that it is stimulated to adapt and supercompensate compared to where it was before. And that’s a necessary component of high performance athletics.

[Damien Blenkinsopp]: Okay, okay. So it sounds like everyone — although it’s not going to lead to a higher baseline, by the sounds of it. If we think of we’re trying to increase our HRV over time in terms of kind of aggregate, rather than the ups and down adjustment cycle of just trying to time our training properly, doing a little bit of aerobic with our strength training probably isn’t going to increase the baseline. It just may help us to get back to another workout sooner than later in terms of recovering quicker. Is that a fair assumption?

[Simon Wegerif]: Yeah.

[Damien Blenkinsopp]: Or would that be, actually, kind of biasing the result, and it would be better to — I guess this area isn’t 100% clear as yet.

[Simon Wegerif]: It isn’t 100% clear. I’m trying to recall my own experience of doing a lot — because I’ve prepared for a pretty long cycling event across the Alps this summer, and I did a lot of hours of fully aerobic training, so I was very careful to keep my heart rate and intensity level below the first lactate threshold, and I accumulated a lot of hours, basically, about 15, 17 hours a week for about four or five weeks of this. I didn’t actually see my HRV baseline rise much. What I did notice was my resting heart rate went down during that period, though, and that was a very clear trend.

[Damien Blenkinsopp]: Okay, so let’s talk about that, because I know that’s something very important to ithlete. You track the HR, the resting heart rate, as well, and you use that in your assessment. And you see it as an important part. So what is the HR for you? What is it doing in terms of tracking and helping you to understand performance and recovery and so on?

[Simon Wegerif]: Well, resting heart rate, most people who do training and even people who know about health would recognize that a lower heart rate — a lower resting heart rate is very often a good thing. And most of the time, that it true, because it’s actually the ratio of your maximum heart rate to your resting heart rate that determines your VO2 max. So there is, for instance, a ready reckoner for VO2 max, which is your maximum heart rate divided by your resting heart rate times 15. So, you know, as your resting heart rate decreases, provided your maximum heart rate stays the same or only decreases a very little bit, then your VO2 max will increase.

Now, there are also situations, which can be due to either non-functional overreaching, so some states of overtraining, or even —

[Damien Blenkinsopp]: When we say non-functional overreaching, what does that mean?

[Simon Wegerif]: Well, non-functional overreaching is basically what you might think of as the third stage in progression of training load and recovery imbalance. So the first stage is shock, also known as the alarm stage, which is the body’s healthy response to a new stressor. And during that stage — so you do something intensive, your body is temporarily stressed. It reacts with an increased sympathetic tone, increased output of central stress hormones, increased adrenaline, norepinephrine, cortisol, and if you then allow time for the body to recover, then it supercompensates, and you actually end up you are a little bit fitter than you were before the stressor had been applied.

Now, overreaching is a deliberate imbalance of training and recovery, usually over a short period of time within a periodized block. So a lot of endurance training programs are periodized into a month or a 5-week block whereby you have a progressive overload, then, you know, ending up with a taper or a recovery week. And that is called functional overreaching, because you deliberately continue to stress the body, and then in the last week, you taper, and you supercompensate, and, you know, the benefits of training are imbedded in your system.

If the balance of training and recovery is such that, you know, your body really — it can’t cope with the amount of load that’s being applied, and that can include environmental conditions as well, so that can include bad diet, lack of sleep, all these other things which are, in fact, stressors to your body as well as training, then if, you know, after a short taper period you don’t recover and supercompensate, but you stay in the hole, as it were, then that’s non-functional overreach.

[Damien Blenkinsopp]: Uh-huh, okay.

[Simon Wegerif]: But people do even go beyond that. It is — yes, it is really — the way I would define non-functional overreaching is that when you take the training load away, you don’t see recovery or supercompensation within a few days or a week.

[Damien Blenkinsopp]: And does it take much longer, or would you have potentially basically lowered your baseline by overstressing the body?

[Simon Wegerif]: Yeah, and it can take weeks to recover from non-functional overreaching. And non-functional overreaching is still not as bad as true overtraining. True overtraining is really quite a serious condition, and it’s not that common, but it can takes months or even years to recover from. It can —

[Damien Blenkinsopp]: How would you differentiate the two?

[Simon Wegerif]: Yeah, true overtraining, again, is an extension of the states of overreaching, whereby you take away the training altogether, and the individual really remains in a chronically stressed state. I think it is quite rare, although certainly we’ve been contacted on a number of occasions by athletes and coaches who know that they are overtrained. And this is also known as the exhaustion phase in the General Adaptation Syndrome. And the body is basically continually failing to adapt to the chronic stress. And the chronic stress also starts to burn out the adrenal system, so the central nervous system starts to shut down production of central stress hormones. The adrenal glands themselves desensitize.

A sympathetic response is normally quite healthy.You know, when a person needs to have a fight or flight response, they want to be able to turn it on and turn it off again quickly. When somebody’s overtrained, that response is pretty much absent, to be honest.

[Damien Blenkinsopp]: Right. We talk a lot about the importance of parasympathetic. In one of our previous interviews, we talked about the fact that most people are sympathetic dominant, mostly because of lifestyle reasons today, and so on. So in the HRV Sense app, for instance, Ronda Collier, she noted that most people have a very high sympathetic in their LF, and their HF tends to be much lower. And over time, they can, you know, look at that for stress and so on. But now we’re talking about also that overdominance of parasympathetic can be a problem? Is that associated with adrenal fatigue?

[Simon Wegerif]: Yes, indeed. Once the body gets itself into this state whereby the sympathetic response is essentially impaired, then — it’s interesting. I mean, that’s a pretty bad state, right? I mean, that’s also a state where protein synthesis becomes impaired, so, you know, muscle damage becomes much more likely. Decreased testosterone and other anabolic markers, increased baseline cortisol, so basically, you know, the body is in quite a stressed state, although it’s sensitivity to the adrenal family of hormones has been reduced. And then, you know, parasympathetic becomes essentially dominant. You swing to a high HRV, which if you weren’t looking at heart rate, you might say that that’s a good state, right?

[Damien Blenkinsopp]: Right, right, right. So let’s be clear. What would the heart rate be doing that’s different to show that this is a negative HRV despite the fact that it’s high?

[Simon Wegerif]: Yeah, so what actually happens is that the resting heart rate decreases pretty significantly compared to your normal range. So all of the ithlete measures are based on solid statistics and smallest worthwhile change and things like that, so we’re always tracking rolling means and rolling standard deviations. We can look at the heart rate and see if that all of a sudden — you know, if that over a short period of time goes much lower than it should do normally, and coupled together with an unusually high HRV, then that is quite characteristic of parasympathetic dominant sympathetic burn out state.

[Damien Blenkinsopp]: Right, right. Have you come across many cases of this?

[Simon Wegerif]: Yeah, I’ve certainly see it in myself. We first came across it, because it’s not that well documented, so most of the textbook stuff on overtraining tends to talk about sympathetic dominance, and indeed that is the case through functional and non-functional overreaching. But then, you know, when people keep going, and there are some very motivated type A individuals that keep on going, and they get themselves further into this — into this truly overtrained state, the first time we —

[Damien Blenkinsopp]: Right. So would it be correct to say that your HRV would go down for a while, and if you ignore that, then you might get to this situation?

[Simon Wegerif]: Yes, absolutely. That is exactly what we see.

[Damien Blenkinsopp]: Right, right.

[Simon Wegerif]: The first time we noticed this, in fact, was in the beta testing of the original ithlete app in 2009, when we gave it to a national standard runner and triathlete, and he did a three-day running event in Southern England over the South Downs, and he said, ‘Hey, you know what, guys? My HRV was really high this morning, and I’m completely knackered. You know, what’s going on?’ And we started to look into it and talking to some researchers and developed this test, basically, out of that.

And we certainly have seen it a few — you know, a few times. I’ve seen it a couple of times myself. In fact, the day after I finished the Haute Route Alps, which was 1,000 kilometers in seven days across the Alps, I was six hours a day on the bike working quite hard, the day after that, the Sunday, my HRV all of a sudden swung from low, which had been progressively decreasing during the week, and it swung very high, associated with a much lower than normal resting heart rate, and ithlete went — gave me a straight red.

[Damien Blenkinsopp]: Right.

[Simon Wegerif]: So ithlete doesn’t mess about in that situation. It gives your a red card straight away.

[Damien Blenkinsopp]: It’s nice that it does that, ‘cause, you know, often I imagine most of the apps don’t pick that up, that scenario. So in terms of a swing of HRV, do you remember your — just to give people an idea, where did it kind of start from baseline, and it lowered steadily to what, and then it jumped up one day?

[Simon Wegerif]: Yeah, I can’t remember the numbers right now. I did do a blog post about it, in fact, so it’s on — yeah, myithlete.com/blog, I did a blog post about my HRV before, during and after this actual event. I think you can go look at that.

[Damien Blenkinsopp]: That’s good. So we’ll put a link in the show notes to help people. Okay, so this final thing on adrenal fatigue, is adrenal fatigue is a widely discussed topic today, because a lot of people, not just people who are training, but often it’s the weekend warriors, the people who are working during the week, and they got out and have pretty stressful jobs, and then they’re training at the weekends, or they’re doing triathletics and all these other things at the weekends. And there’s this question of when they start getting more and more tired is the adrenal fatigue. Doctors and clinicians argue about this and how to test for it. And many of the tests are considered not ideally accurate, there is saliva test, there is blood tests, and there’s a bit of discussion there. So I’m just wondering whether you think this would be a relevant biomarker, and if you’ve seen anyone try to compare it to some of those other adrenal fatigue tests?

[Simon Wegerif]: I haven’t. A practical test I could recommend for people, though, is if you suspect you might be starting to get adrenal fatigue, then the likelihood is that you won’t be able to manage high intensity exercise. You know, you simply — you hear comments like, ‘I was unable to get my heart rate or my power up into the right zone.’ You will notice that. And it is literally impossible. You just cannot manage the effort levels, no matter how hard you try. So your perceived exertion would go right up, but your metabolism and your body wouldn’t respond to the workload and energy levels that are required.

[Damien Blenkinsopp]: Yeah, yeah. So I noticed, also, that when you were talking about how to notice this, you know, you spoke about an athlete who came to you and said, ‘Look, my HRV’s really high, but I’m feeling terrible. I’m feeling really tired.’ So in ithlete, you have a bunch of indicators that you track whenever you track your HRV for training, in the morning you have sleep, fatigue, muscle, and stress, and mood, and diet. Do these filter into some kind of algorithm, or how are you using these to help people make decisions?

[Simon Wegerif]: They are going to. I mean, at the moment, these are quite widely used subjective metrics, and they are quite useful for tracking overall health and wellness, as well. So at the moment, it’s great for people to record those every morning, and on the ithlete, if they rotate the dashboard around to the landscape chart, they can visually for themselves see correlations between any one of those variables and their HRV, and in my case, I’m really not very good, if I’m lacking sleep, quality or quantity. So, you know, my HRV normally shows quite a good relationship with my sleep score. Other people —

[Damien Blenkinsopp]: Right. Is that the same for everyone, or do people have different weaknesses? You know, the high leverage weakness you’ve got to kind of avoid. So yours is sleep. Mine is probably sleep, too.

[Simon Wegerif]: No, I think people absolutely do have individual characteristics there. It could be stress for some people, or it could be diet in others, if they have particular dietary sensitivities. But what we are just starting to do, right now, in fact, is a cooperation with a UK university on some advanced statistical algorithms which will look for relationships between those individual subjective variables and the HRV over a period of time. So what we hope to be able to do within the next six to eight months or so is to be able to give users feedback and insight into their own data.

I — you know, for me, HRV has always been a journey of personal discovery. I’ve found out things about myself, what my body and my brain likes as assessed by HRV, and, you know, I’ve been able to keep my HRV sort of steadily trending upwards over the five years that I’ve been doing this; whereas, normally it would decline with age. But, yeah, what we want — what we aim to be able to do is to give users insights, exactly as you say, Damien, telling people, you know, over the past month, sleep was the most important factor for you, perhaps again, and diet was the second, and it seems like you’ve been having a lot of stress recently, and that’s been affecting you as well.

So I think there’s potential for this to go quite a long way, including things like, perhaps, looking at all the relationships between everything people are capturing, and then saying with some statistical confidence all of this stuff that you’re capturing isn’t explaining all the variation we’re seeing in your HRV, is there something else? Is there, for instance, travel?

You know, one of our — one of the members of our team just noticed that driving for periods above three hours was causing a big drop in his HRV the next day. So potentially we can also alert people to things that they’re not capturing or not trying to understand right now, but which nonetheless are affecting their health.

[Damien Blenkinsopp]: Yeah, yeah. So, yeah, just to be clear, because I didn’t bring this up before, but these ratings you enter into your app are basically from, you say sleep quality, and you just give a rating from weak — it’s kind of like 0 to 10, right?

[Simon Wegerif]: Yes.

[Damien Blenkinsopp]: Or you can put very strong, and that’s for each of them. So they’re qualitative measures, but as you say, you’re finding correlations with them, and you’re going to be looking into more of that.

[Simon Wegerif]: Yeah. We turn the position of the slider into a number, like you say, between 1 to 10, and I think that’s a technique — I think that’s called a visual analogue scale or something like that, and the statistics will be using those numbers to determine relations and give people feedback.

[Damien Blenkinsopp]: Right, great. Well, [00:35:23] we’ve explore a bunch of new topics and interesting scenarios that we hadn’t come up with before, because you’ve got this user base which is using ithlete. I think what would be interesting is, like, what do you see people mostly using this for, and what are the kind of biggest use cases, and most useful things people are using it for?

[Simon Wegerif]: We’ve got a wide variety of users. We’ve got well over 10,000 users now on the ithlete app, and they really vary. They do vary from weekend warriors to — all the way through to top professional athletes, both in team sports, endurance sports, things like boxing as well, through to health and wellness practitioners. So we certainly get quite a few bulk orders from chiropractors and holistic wellness practitioners and people like that. And I think it’s used for all kinds of things. It’s used by health conscious people who just think HRV is a good metric to track every day, and, of course, it is. It’s a sort of holistic measure of adaptation reserves or overall well being. So it’s a great thing for people to track.

I think in the more serious side of sports, people are looking in their training not to have dug themselves into too much of a hole, and they fairly quickly start to take the tool seriously when they get amber and red warnings, and they still go training on those days. They fairly quickly work out that that’s a bad idea, and they start to trust the tool more. We give them feedback on a day-to-day basis.

[Damien Blenkinsopp]: Is there any scenario where you wouldn’t trust it? I mean, we’ve highlighted one that you’ve identified and you’ve integrated now into ithlete, with that one HRV going up. Is there anything else you’ve kind of got on the horizon? Maybe there’s a couple of other scenarios that need to be looked into?

[Simon Wegerif]: Yes, definitely. One of those is taking readings at an unusual time. So the ithlete algorithms are based on you doing things at the same time every day. Ideally, it should be first thing in the morning, because then you haven’t got additional variables of drinking a coffee or not, or having something to eat, or looking at — opening emails, having an argument, anything like that. Those variabilities all eliminate it. And, of course, another advantage of doing it first thing in the morning is that you can plan the day ahead. So, you know, darn, I got an amber instead of a green, but it’s not too late, I can modify my training or something else that I was going to do today.

[Damien Blenkinsopp]: Yeah, that’s interesting, because in a future episode, I want to have someone talk about willpower, because I’ve read a fair amount about the correlation between HRV and willpower, and, you know, basically motivation and drive. So if I have a low HRV one day, I’m, like, okay, I’m going to take on less and less business tasks today. I’m going to focus maybe on one instead of trying to get five done. I kind of factor in like that. I mean, obviously you’re feeling like that as well, but I’m also kind of aware that maybe I need a recovery day in terms of just taking on work stressors and mental stressors and things like that, in order to be able to take on bigger stuff the next day and so on.

[Simon Wegerif]: Absolutely, or there might be some intervention which will help you a bit. So if I get an amber in the mornings, then I often, you know, I will change my training to an hour aerobic bike ride around a particular route in the local forest that I really enjoy, that, you know, is visually stimulating. And I know that will help me make the best of my current physiological state.

But back to the question you were asking about when would you not trust ithlete, or in fact any HRV product that compares to baseline, and that is if you get up significantly earlier or later than your normal time. So one of the things about the waking measurement is that you are taking it after you’ve had the cortisol awakening response, so basically when light starts to fall on the back of your eyes, even through your eyelids, it kicks off the cortisol awakening response, which basically gets your body ready to get up and start being active again. So it banishes the melatonin, and it starts the sympathetic nervous system to a certain extent, enough to get you out of bed and get moving in the morning.

Let’s say you normally do that at 7 a.m., and then one morning you have to get up at 4:30 in order to catch a plane or something like that. This is something that I noticed quite early on, that my HRV would, in that situation, be much higher than normal.

[Damien Blenkinsopp]: Ah, because parasympathetic is higher.

[Simon Wegerif]: Yeah, basically. Because my body was still in sleep mode, so the parasympathetic was dominant at that time.

[Damien Blenkinsopp]: So, basically, the circadian cycle is very important to control for.

[Simon Wegerif]: It is important to control for, and some people — I think everybody, once they realize that, that really your morning measurement should be +/- 45 minutes, something like that —

[Damien Blenkinsopp]: So I’m thinking jet lag is — because I just came from Europe to the U.S. a few weeks ago, and my HRV has been a little — I think I was surprised to see how high it was, given how tired I was feeling. So maybe that had some of the impact there.

[Simon Wegerif]: It could do. It could do.

[Damien Blenkinsopp]: Or do you think you adjust pretty quickly in terms of that cycle?

[Simon Wegerif]: I don’t think you do adjust that quickly. We’ve had so many stories reported back to us over the past few years. An Australian coach has said, ‘I never realized what an impact jet lag had on my body,’ and that was by doing HRV measurements, and he was flying backwards and forwards between Australia, Europe and America. And those are long haul flights. I think one rule of thumb is something like your body needs a day to adapt its circadian rhythm to each hour of time zone change. So if you’re doing all that trans-Atlantic or trans-Pacific travel, you’re going to have a really hard time getting adjusted, and your HRV is going to give you feedback on that.

[Damien Blenkinsopp]: Yeah. So the only other confounder is basically the issues is controlling for circadian rhythm and other things you’re introducing, like caffeine or those things. But in terms of actual scenarios, the only other one you’ve seen is where you continue to overtrain and eventually get to this adrenal fatigue situation, without introducing — and then the other scenarios are where you’ve introduced either a circadian or some other confounder in terms of stimulant or activity which is influencing your HRV?

[Simon Wegerif]: Yes, I would say so. Water has some interesting effects on HRV. Hydration level is something that — you know, some of the professional teams that are using ithlete, they want to control hydration level.

[Damien Blenkinsopp]: So are you saying dehydrated would lower your HRV, potentially?

[Simon Wegerif]: Yes, because it stresses the system, so, yes, that will tend to make you more sympathetic dominant. But, of course, that’s something that’s quickly fixable, right? You drink water, and within 15 minutes that HRV will have been restored, because your body absorbs water so quickly. So that will give you a false low.

[Damien Blenkinsopp]: Right.

[Simon Wegerif]: So if you woke up dehydrated and you were normally fully hydrated, you will get a falsely low — I mean, it is a low HRV at that point in time.

[Damien Blenkinsopp]: It’s relevant, yeah.

[Simon Wegerif]: But you have to take it — it’s relevant; it’s important, but you don’t have to take it easy the whole day —

[Damien Blenkinsopp]: Yes.

[Simon Wegerif]: — because recovery from that particular situation can be very rapid. You just drink large glasses of water and you’re right as rain.

[Damien Blenkinsopp]: That’s a good point. It’s a momentary HRV lapse, a decline. Are there any other scenarios where there are HRV’s you can quickly addressed? I’m thinking training scenarios. I mean, obviously, there’s, maybe a stress scenario, caffeine and things like that.

[Simon Wegerif]: Yeah, mental stress is important.

[Damien Blenkinsopp]: So people can account for those kind of things by — hopefully, if they’ve identified it, then they can retake their reading in an hour or so and see if it’s readapted to their usual baseline.

[Simon Wegerif]: Yes, they certainly could do that, yup.

[Damien Blenkinsopp]: Okay. Well, so you’ve talked about some of the things you’re going to be doing in the future with the algorithm and the correlation. Is there any other future developments and things that you — like, if you’re looking at the whole HRV app space, is there other things you’re looking forward to or that you see could be possible in the future, 5 or 10 years? Where do you see it all going?

[Simon Wegerif]: Well, what I personally hope for is that HRV, it is starting to get credibility now in sports training and sports performance. You know, it’s becoming, thanks to some of the really quality research that’s being done, it’s becoming more and more trusted. I’d like to see HRV trusted as a precursor to Western chronic disease, and in particular I mean conditions like high blood pressure. High blood pressure is an autonomic imbalance disease, and basically high blood pressure can certainly be caused by chronic stress over a period of time, and the blood pressure regulatory mechanism starts to go adrift. But you will see, in the case of not only high blood pressure, but type 2 diabetes as well, that HRV will go out of what ought to be considered acceptable normal ranges months or even years before those diseases take hold.

So what I’d like to see is HRV used as an ongoing wellness barometer, if you’d like. So I’d like to see normality of standards create for HRV measures, and for those actually to be something that people do, perhaps on their own initiative, but something that primary care physicians, general practitioners, etc., are happy to discuss.

[Damien Blenkinsopp]: Yeah, because — I mean, today we take our — if we go to the doctor for a standard checkup, we have our blood pressure and we have our heart rate, standard heart rate taken. What you’re suggesting is potentially HRV could be a better measure, and it should be included in those, if we could be more standardized and stuff, because you’d see it decline steadily over time if there were some chronic issues building.

[Simon Wegerif]: You would, and you would see it declining outside of a normal range. We exhibited — we launched the finger sensor in V3 of the Apple Consumer Electronics Show in Las Vegas in January. We probably did 200 demos during whatever it is, the three days that CES is on, and we had people who illustrated HRV values which, by looking at them, some of them were predictable, and in some cases, people really needed to pay attention. So we had a very large gentleman who came to see us, who said he got diabetes and he hadn’t been exercising recently, and he got 35 on the ithlete scale. And that shocked even him, because that is a very low number. I mean, that’s an extreme case, but —

[Damien Blenkinsopp]: Was that lying down or standing?

[Simon Wegerif]: No, that was sitting. So we did — all of these demos were done with people basically sitting at a table. But I would like to see some normative ranges exist for people. And also by tracking over weeks and months, that they’re able to do what I’ve seemed to been able to do, which is to basically find ways to keep my HRV increasing over the long term as opposed to declining with age. HRV is a very good forward looking indicator, and that’s why I sometimes call it a barometer. You know, it’s telling you about the weather to come, rather than the weather as it is right now. I would like to see it accepted and accredited.

And I think there’s been a useful start made in that area recently. There’s been this announcement about the Palo Alto prize, and that basically is, I think, either a half million or even $1 million award to researchers who can show initially in laboratory animals that they’ve developed techniques which would cause animals’ HRV not to decline over a period of time. The idea is that that will be applied to human studies later on, once the techniques are proven. So HRV is starting to become recognized now as a longevity indicator.

[Damien Blenkinsopp]: Right, right. You wouldn’t have seen it yet, but we also interviewed a guy named Todd Becker who’s very interested in hormesis and aging and longevity, and you might have read his stuff.

[Simon Wegerif]: Yup.

[Damien Blenkinsopp]: He plays around with that to increase HRV.

[Simon Wegerif]: I did read it. His article on HRV was excellent, really, really good.

[Damien Blenkinsopp]: Yeah, so he has some interesting points on that. Look out for the interview when it goes up, because it has some relation with this discussion.

So in terms of places where people could go to learn more about this, are there any people or particular journals where you think are good sources of information about HRV?

[Simon Wegerif]: One of my observations about HRV, there’s this massive body of research out there, but unfortunately it’s largely untapped, and I think that’s partly due to the impenetrable nature of medical research language. What we have tried to do is also to summarize a number of what we regard as some of the most important articles. So on the ithlete blog, we have done a number of research summaries where we’ve tried to take — captured the essence of what we regard to be some of the most important papers and put it up there for people to look at.

Also, we’re doing a new website where we’ll be putting more resources in there. I think Todd Becker’s article is an excellent introduction to HRV with a really good — a really good, if you like, approach to experimenting with different interventions on himself to see what made a difference. I think Andrew Flatt is doing some very good work at HRVtraining.com. There are a few sites around. And even Men’s Health carried an article or two on HRV over the past year.

[Damien Blenkinsopp]: Was that a good quality article, or was it just good that it’s getting the word out there?

[Simon Wegerif]: It’s good that it’s getting the word out there. I think reasonably brief at the moment. But HRV is getting more mentions in the mainstream press, which I think is important.

[Damien Blenkinsopp]: Great. Okay, so I’d like to round off with a couple of personal questions. I always like to get some information about how people like you, who’ve obviously spent a lot of time thinking about data on biology and working with it, actually make use of it. So what kind of data metrics do you track for your own body on a routine basis? HRV, I guess, obviously. But beyond HRV, or in the specific context of HRV?

[Simon Wegerif]: I’m always wrestling with how to quantify my training. So training load is something that’s interesting to me. And I don’t think that any of the existing measures are really adequate.

[Damien Blenkinsopp]: So is that — are you talking about cycling or — you’re talking about volume?

[Simon Wegerif]: Yeah, that is the point. So training load metrics, there are many of them. So how do you quantify any kind of workout? If it’s cycling, is it miles? Is that a good — is that a good indicator? Is it average heart rate? Is it something about zones, the amount of weighted addition of all the zones you are doing? In team sports, they use RPE a lot, which is rating of perceived exertion. They also do translations from GPS data using group statistics for acceleration levels and running speeds and things like that.

But all of this training load stuff, what are we trying to achieve exactly with respect to — you know, training is all about stimulus and adaptation. From what I can see in endurance sports, there’s two completely different kinds of stimulus that we provide to the body, both of which seem to be necessary, and both of which are very helpful. One is this aerobic stimulus, which some people call the long, slow distance, and the other one appears to be the high intensity stuff. So how should we quantify each of those, other than by observing Kenyan runners who win all the long distances races and seeing what they do? I’m really interested in the science and the biology and the physiology behind that.

There’s all the stuff about calories. How do we measure calories? Why do we measure calories? What exactly are we going to do with that information? That stuff is of interest to me. Calories was of interest, before I did this trans-Alpine cycling, because I wanted to lose weight, but I wanted to do it in a controlled way, and in a safe way as well. So I didn’t actually damage either my health or my sports performance, but I wanted to lose 7 kg, just a stone, a reasonable amount of weight, and I wanted to do it very safely.

[Damien Blenkinsopp]: So you focused on calories to do that?

[Simon Wegerif]: I ended up actually focusing on food types. So what I actually did as advised by my good friend, Dr. Mike T. Nelson, was actually just to deliberately introduce a lot more protein into my diet, and basically diet — there’s an easy way and a hard way to diet, and I think the hard way is to think about all the things that you can’t do. And I think the easy way is to introduce good stuff, and that will necessarily push out some of the other things.

And what I mean by that is — Mike’s advice, specifically, was to increase my protein intake dramatically. And one of the ways I chose to do that was by having a big omelet after training in the mornings every day. And that actually makes you much less hungry during the day for snack foods, biscuits, carbohydrates, things like that. I also asked my wife not to buy biscuits and not to put biscuits in the — or cookies in the cookie jar, so that those were just sort of taken out. I was also — with chocolate, I just said I’m only going to have two squares of 70% chocolate a day, and that’s okay. Because 70% cocoa chocolate is so strong that you don’t want lots of it anyway, but it does sort of just satisfy that need.

So by deliberately eating lots of protein, I basically pushed out quite a bit of carbohydrate, and that combined with the volume of training actually tailed my weight down quite nicely.

[Damien Blenkinsopp]: Right. You make an interesting point in calories, because there’s a lot of devices coming out to measure calories. One of the areas of investment. And obviously that’s been a huge focus for the last 30, 40 years in diet books and so on. However, there’s a fair amount of research now to say that calories are not necessarily the whole thing, input and output, and that it’s a bit more complex than that.

In our discussion with Jimmy Moore a couple of weeks back about focusing on fat. You focused on protein. He focuses on fat intake, and it has the same impact. It satiates you and you tend to lose weight, and you’re not counting calories.

Yeah, so this is arguing whether it is useful to count calories, and these are the kinds of discussions I love to bring up, because especially when the marketing and everything that is out there is saying, ‘Let’s count calories; it’s going to change our behaviors; it’s going to have an impact on our lives.’ But is it really as beneficial as it’s portrayed to be, or are there better methods, like we’re doing — we looked at using the ketonics, which measures your state of ketosis, and as long as you’re staying in a state of ketosis, you’re going to be losing weight. So there’s other approaches to it that may be more useful, depending on what you’re doing.

And the training load thing, I think, is also interesting, and difficult, as you said. There’s not really any measures. We talked to Doug McGuff from Body By Science. He has a very specific protocol which kind of allows to do that, but you have to use that exact training protocol; whereas, I think what we kind of really need to get to is like you were talking about, is we have the metabolic and the strength, or as you call it, the aerobic and the —

[Simon Wegerif]: The high intensity HIT.

[Damien Blenkinsopp]: The high intensity stimulus, and how do we quantify those? Is there any way to quantify those so that we can see what stressor we’re getting, and then we can see, oh, we got a decline in our HRV because it was that stressor. Right? And currently you’re trying to do this with qualitative measures, which is pretty much the best I’ve seen that exist today as well. I don’t know — so you haven’t seen anything? It seems you haven’t — on your journey looking for that, you haven’t yet found anything that might be better than a qualitative measure?

[Simon Wegerif]: No. I’m always looking for things which are practical, which people will actually do every day. So anything which is too complex to calculate, people might do it a few times out of interest, but then it’s not going to imbed itself as a habit.

One thing I will say about calories, though. This whole motto of ‘What gets measured gets done.’ So giving people some kind of feedback that they can relate to which motivates them is always important, and whether that’s steps or whether that’s calories, I personally don’t mind, so long as it motivates them to imbed good habits and to reach for smart targets and goals.

What I think the particular problem I have with calories is that, yes, perhaps you can measure calories out, calories expended. Calories coming in is pretty difficult, though, unless you’re really going to spend a lot of time not only looking at the back of food packets and weighing things out exactly, which can be done, but at the end of the day, it doesn’t seem to work out that well, either. I mean —

[Damien Blenkinsopp]: It’s very impractical. It’s very time consuming.

[Simon Wegerif]: It’s very impractical, and it doesn’t actually work out that well. So people who’ve tried to do this very exactly, like Nigel Mitchell, who is the consultant nutritionist for Team Sky and is a very well recognized and respected nutritionist, says that if you do this exercise exactly — so on professional cyclists, they use power meters. You can measure the exact number of joules that they have expended. They can also measure the efficiency of the cyclist in terms of oxygen consumption, they can work out very accurately how many calories in those guys should need, and even if you do do all the food weighing stuff and measuring and everything else like that, the weight balance doesn’t seem to come out exactly as you would have hoped. There’s some quite large inaccuracies in there, one of which I believe is potentially the fact that the calorie numbers on the back of the food packets are achieved by burning the product in pure oxygen and seeing how much heat it gives off, but to what extent does that really represent the way our digestive systems work? And do they always do the same thing with two forkfuls of pasta? Does it matter, you know, what else you’ve got in your stomach at the same time?

[Damien Blenkinsopp]: And your microbiome, which is another interview with recently did. Like, your microbiome can impact how you metabolize the food. So I think it is more than calories, and it seems like the research is steadily going towards that, but it actually seems pretty complex. You know, microbiome, the types of macro and micro nutrients that you’re consuming. But, as you say, if you’re counting calories, you’re potentially looking at helping yourself to behave better, so it potentially could help.

Just, I think there is a device and a crowd sourcing project which is tracking calorie input, so in a more convenient method, I think it’s still in crowd sourcing. I’ll put the link in the show notes, because I can’t remember the name of it, but it would be interesting to see if that one works out. Because, yeah, like noting down everything you eat is not something that I can see people doing for a very long time.

What has been the biggest insight about your own biology that you have drawn to date from any data or anything you’ve tracked?

[Simon Wegerif]: I will tell you, I haven’t mentioned before in this discussion, but it is actually HRV — so HRV biofeedback, which is another — another topic in its own right and may be one that you will cover in a future podcast, but one of the things in my journey to steadily increase my HRV was — I do tend to be quite a driven person. I do tend to get moderately stressed, and my wife is much calmer. She’s been doing yoga for a number of years, and she’s always told me, ‘Simon, you should try yoga breathing.’ And I must admit, I did poo-poo it a bit, until I actually had a chance to meet up with an old friend who was a yoga instructor, and he told me about breathing. And I started to relate that to HRV, and I built myself a little biofeedback app prototype, and that, over a period of just a few days, made a big change upwards in my baseline for about 5 or 6 ithlete points.

And that was a really — that was a really big insight for me, that I could increase my HRV and feel much better quickly by using basically guided, deep diaphragmatic breathing. And there are good reasons as to why that should work.

[Damien Blenkinsopp]: You were tracking — you were doing this for, like, what 10 minutes a day or something like this? And you were using an HRV device to see if you were raising it? Or were you just using the HRV for training every day, and just watching it? So it was like an experiment?

[Simon Wegerif]: It was like an experiment. I did my ithlete reading every morning, and then, I mean, you couldn’t help but notice how much it had swung upwards when I started doing this breathing practice. And what I found even more surprising was that when I experimented again by not doing it for a few days, my HRV remained elevated. So it seems to have a chronic effect on upwards HRV. And I think this is a technique that’s got a lot of potential for the future as well.

[Damien Blenkinsopp]: Yeah, very interesting. Great, great point. Okay, last question. What would be your number one recommendation to someone trying to use some form of data to make better decisions about their body’s health or performance?

[Simon Wegerif]: I think it would be do it consistently. Do it consistently. Preferably, you know, every day or several times a week, and do it for a period of time. And when you’re trying to — if it’s a measure that you’re trying to improve, like HRV, try to change just one thing at a time to see if that thing does make a difference. So just be a little bit scientific in what you do and how you do it. Because otherwise, you know, there’s so much data around now that actually deriving information from that data is in some ways getting harder, because there’s more and more data, more and more variation in it.

[Damien Blenkinsopp]: Great, great point. And yeah, the information overload is going to get worse as time goes on, because there’s so many devices and things coming out. I know I already have too many devices, and I’m trying to decide which ones I focus on. And HRV happens to be one I very consistently do, because it is very rewarding, and I notice the changes.

So Simon, thank you very much for your time today. It’s been a great discussion, and I can’t wait to put this out on the podcast.

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What is it that makes our bodies stronger? Gives them greater longevity? Greater resilience to disease? Greater performance?

The strange answer to this is that often something that harms us, stresses us, is what ends up making us stronger. The process is known as “hormesis” and applies to pretty much everything we can think of. Low doses of all types of stressors can make us better by stimulating us to adapt – exercise, emotional stress, radiation, natural pesticides found in plants – also known as phytonutrients and so on.

When the dose is too high it proves to do the opposite – make us weaker. So it’s about balance – but how do we know when we get the “dose of stress” just right so that we get positive results?

Today’s guest, Todd Becker, runs the popular blog GettingStronger.org dedicated solely to the topic of experiments in using hormesis to improve HRV so we may improve our lives. Todd is a scientist from Silicon Valley working in biotech, and runs his own N=1 experiments with hormesis in a wide variety of areas from improving eyesight to improving estimated longevity and general health.

In particular he’s experimented with improving his baseline and temporary Heart Rate Variability, as a proxy for longevity, with a long list of activities, from the well researched to the more experimental. In this show he talks about the outcomes, what worked, what didn’t and the usefulness of tracking heart rate variability for general health and longevity.

The show notes, biomarkers, and links to the apps, devices and labs and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

Show Notes

  • What got Todd started on his mission to experiment with hormesis – an experiment that reversed his myopia.
  • The hormesis framework, AKA the body as an adaptive system, with all the areas our health is modulated by hormesis.
  • Phytonutrients as natural pesticides, or toxins, and the work of Dr. Bruce Ames.
  • Can the gut microbiome also be improved via hormetic mechanisms involving probiotics?
  • The need for balance of the intensity of the stimulus given to your body to provide positive benefits.
  • Using lenses to stimulate growth in eye muscles, addressing myopia, sometimes in a matter of hours.
  • Why Todd sees the Heart Rate Variability biomarker as more useful than the majority of markers and chose it as the end result to aim for and measure.
  • A review of how heart variability works and illustrates our ability to adapt to stress.
  • The inverse relationship between the heart rate and heart rate variability markers.
  • The positive impact that cold showers can have on your HRV throughout the day.
  • How Todd increased his baseline HRV by 10 points over several months through eliminating a variety of lifestyle habits or modulating them.
  • Using fasting (also known as intermittent fasting) to increase your HRV.
  • The major factors Todd found that reduced HRV including alcohol, hot tubs and exercise.
  • Linking someone’s HRV to how they respond to emotional stressors and how additional stressors like alcohol can magnify emotional behaviors.
  • The amazing power of vacations to increase HRV, regardless of how you feel – food for thought before you skip that vacation this year.
  • Biomarkers Todd routinely tracks and finds useful to keep track of and his perspective on the value of tracking vs. anecdotal experience.
  • Todd’s and Damien’s benchmark values currently for HRV when well recovered or more stressed.

Connect with Todd on Twitter to thank him for the advice in this interview.
Click Here to let him know you enjoyed the show!

Todd Becker & Getting Stronger Blog

The Tracking


  • Heart Rate Variability (HRV): Measures how your heart rate varies over time. Research studies link HRV to recovery status, stress and other aspects of human physiology. We have looked at HRV from a variety of perspectives in a number of episodes covering HRV.
  • Average Heart Rate (commonly referred to as heart rate): A high resting heart rate can be indicative of bad health, while a lower resting heart rate can be indicative of good health and fitness. Todd discusses how average heart rate often correlated negatively with heart rate variability.

The Tools

  • Cold Showers: Cold showers are a form of cold therapy that can be used at home to encourage the body to adapt. Todd’s experiments revealed that his HRV improved using these.
  • Intermittent Fasting / Fasting: Fasting involves fasting for several days typically, while intermittent fasting is based on a daily cycle. Standard approaches to intermittent fasting are 20 hour fasts, or 18 hour fasts.
  • Avoiding Alcohol: Alcohol effects HRV negatively so avoiding it or quitting it temporarily or permanently should enable you to improve your HRV.

Other People, Resources and Books

Full Interview Transcript

Transcript - Click Here to Read
[Damien Blenkinsopp]: Hi Todd, great to have you on The Quantified Body show. Thank you very much for having your time available today.

[Todd Becker]: It is great, I am happy to join you.

[Damien Blenkinsopp]: So you have got a very interesting site, which is pretty much very dedicated to the topic of hormesis, which is called getting stronger. Could you tell me particularly what prompted you to take an interest in hormesis and this topic when you first started out?

[Todd Becker]: Well, it wasn’t any one thing. I just noticed certain patterns in what made me healthier and it really came from a variety of different areas. I would say probably one of the most pivotal experiences was learning that I could improve my eyesight without glasses, and that was probably almost 15 years ago, and understanding that the eye can respond to stimuli and the vision can improve, very [inaudible 00:03:18] to the way that weightlifters gain muscular strength by going into the gym and training. And then I started to think about how that is try about so many aspects of physiology from the immune system, which benefits by being tested and exposed and I think autoimmune and immune problems come from an underactive immune system or an overactive immune system.

It is not trained properly, thinking about how calluses form on the feet when you walk barefoot and how when I started doing barefoot running rather than these cushy shoes providing benefit by cushioning me and protecting me or actually weakening me and by exposing my feet and my calves and knees and really the whole musculature to the shock that it was designed to withstand actually got stronger and less prone to injury and then thinking about how bones and the skeletal system responds and it really almost requires stress when astronauts go out into space and experience weightlessness. They rapidly lose bone density and it is hard for them to regain when they return, so really just starting to think about the body as an adaptive system and think about the factors that influence that.

Then I did some reading and I think for me it was just the concept that lies really at the nexus of all of those different adaptive phenomenon.

[Damien Blenkinsopp]: So how long have you been playing around with this idea?

[Todd Becker]: I think if you go back to the vision improvement idea that is 15 years and even before that I think another experience that led into this low carb dieting, which I first encountered in the mid 90s, I didn’t really realize at first that ketosis is a form of hormesis but what happened is I started to think about this framework and how much you can explain with it. And of course it doesn’t explain everything and it is certainly not the only factor in health but I think it is an important one and it has been overlooked so that is why i felt that there would be an intro in a blog that really focused on that concept.

[Damien Blenkinsopp]: Right, I like the way you put it. It is a nice framework to be able to look at things and I know you have done a bunch of your own experiments, so that is what I wanted to talk about. Before that, give people an idea of how broad this is. There are a whole number of topics you have looked at and referenced, like exercise you brought up, phytonutrients in plants, like some of the things that we thought had antioxidative and protective effects actually are working on a basis of hormesis as well. You talk about sunlight, radiation – have you looked at the topic of pesticides?

[Todd Becker]: A little bit. I would say that I guess when we talk about phytonutrients these are really natural pesticides if you think about it in this biological arms race where plants want to avoid being eaten and predators want to eat them. So they develop more and more effective toxins to scare you off but predators that are able to detoxify those natural pesticides get the spoils. So it is kind of this back and forth but as far as artificial pesticides there is probably some element that we know there has been a somewhat controversial analysis of dioxin which is highly toxic and actually has some hormetic benefits at low dose. So even artificial toxins can play that role.

[Damien Blenkinsopp]: Yeah, you are aware of the work of Dr. Bruce Ames?

[Todd Becker]: Yes, right, I think he was instrumental there and he certainly has been critical of modern toxicology and the sort of linear, no threshold concept that everything is toxic down to the tiniest measurable dose. Even though he developed some of the institutional tests, like the Ames tests that are used to look at mutogenicity or carcinogenicity, he is critical of over-extrapolating with those tests. But just for your listeners who don’t really understand the technical concept of hormesis it is really the idea that something that is damaging or toxic at higher doses can actually be beneficial at lower doses. At first that seems like a paradox but then you realize that evolution required us to survive in the face of all kinds of stresses including toxins and UV radiation and heat and cold and if we didn’t have some method of fending off those stresses either by adapting to them and defending ourselves against them or repairing ourselves or our DNA once we have been exposed, we would perish.

So I think most organisms have some hormetic mechanisms that allow them to adapt to harsh environments and survive. The key is what is that level? What is that sort of magic dose that gives you stimulating effect as opposed to the inhibitory or detrimental effect and it can vary quite a bit. I mean, some substances like alcohol, for example, show hormetic effects at much doses than some, say, metals that are considered much more highly toxic and only showed the [inaudible 00:08:18] effect at much lower doses. And there are a couple of researchers who really have done a lot of good work to kind of document the ranges in which different stresses are hormetic.

[Damien Blenkinsopp]: Yeah, it is very difficult to kind of assess where it is going to be overwhelming. I guess it is not what doesn’t kill you makes you stronger, it is more like what doesn’t overwhelm your system makes you stronger.

[Todd Becker]: Yeah, I think the other interesting thing is if you look at the work of people like Edward [inaudible 00:08:46] that these are the guys who are really documenting all of this [inaudible 00:08:51] sort of static type of hormesis where they will expose say a worm or a plant or a microbe or an animal to toxins and they will find that dose that is causing damage or disease and that dose that is causing a benefit. But what I am also interested in here is the idea that this can be a dynamic type of range that progressively you can become more and more tolerant by gradually exposing yourself to increasing stresses. of course there is always a limit and you can only tolerate so much radiation or UV or exercise or cold and there is a limit. But i think you would be surprised at what that range might be.

[Damien Blenkinsopp]: All right, so going back to your analogy of strength training because I think most people understand strength training and that you are not going to walk in and lift 100 kg the first time, but if you start at 50 kg or whatever as your level, after a couple of weeks you work up to 60 kg and after some recovery you kind of go through this process. You can eventually move up to that 100 and you can say it is very similar and you have an ability to kind of get stronger across all of these different stressors and deal with all of them. Is that the way you look at it?

[Todd Becker]: Exactly. I think that the principle is the same, the details are different in each case. And you hit on I think a key principle of doing this [inaudible 00:10:13], which is gradulous. A lot of people jump in too quickly, have a negative experience, and conclude that they can’t do it. I think a classic example is exposure to cold. After initial, awful exposure people say, ‘I could never do that.’ Or fasting is another good example. Some people try to just jump in and skip meals all day and they will get ravenously hungry or have hypoglycemia and they will conclude that they are incapable of it, not realizing that if you had built up to it gradually you can adapt. So I think that is a key aspect there.

The other thing which you touched on a little bit is rest and intermittency. Weight lifters go in and they will lift heavy weights but they are essentially causing microtrauma or tears to their muscle fibers and they have to allow for the damage to be repaired. And this is true in any kind of overtraining where you are running anything. If you don’t allow that period of recovery you are not going to get the benefit. So I think gradualism and then a progressive increasing and allowing adequate rest and repair, I think these are probably the factors that people overlook and leave them to conclude that this doesn’t really work.

[Damien Blenkinsopp]: Yeah, that reminds me of one of my buddies at University who used to come with us to the gym once every three months and he would hit it really, really hard and he would go home and he would feel horrible for three days and be in so much pain and he wouldn’t come for another three months. You would never get anywhere of course, doing that, and he would be through a lot of pain. So that was a nice analogy. That is not the way to go about getting stronger as the theme of your blog. It is really to take it gradually, as you say, with all of these things.

So what are the mechanics behind how this works? Do we have any ideas about it or is the science very vague at the moment still?

[Todd Becker]: I think you can cluster these things into a few different categories. One is physical changes to tissue, so the example of building muscle. You stimulate – you apply physical stress and cause some damage or change and then allow the tissue to remodel. The same thing is true with bone that you apply to stress. And part of it is directly within the tissue, part of it is the nervous system, part of it is stimulation of hormones, growth hormones, but there is response. Another really interesting example is vision improvement and particularly reversing myopia.

This is a very interesting stressor where by incremental defocus and by causing a slight blur, you actually induce differential growth in the scleral tissue of the eye by stimulating neuromodulators that actually grow differentially and cause the eye to change shape. It happens very gradually over many, many cycles, but there have been experiments in chicks and chimpanzees and then most recently in humans, that fitting people with concave or convex lenses, plus or minus lenses, induce these changes in growth literally within a matter of minutes and hours.

So there are these physical stressors – calluses are another example of a physical stressor that causes growth factors to build up the tissue. So that is one type of hormesis. Then I think there are metabolic processes – for example, real shifts in nutrient balance, for example ketosis, deprivation of carbohydrate and sugar, causes a shift in expression levels of different lipases that causes a reduction in insulin and causes hormonal shifts that actually up-regulate the ability to digest fats. And again, this is a process that might happen over weeks. So there are kind of different time scales.

[Damien Blenkinsopp]: Yeah, just to jump in there – it can be different according to the person where they are starting from, the condition of their body and potentially even their genetics, as to how quickly your – if their ability is to adapt to them.

[Todd Becker]: Certainly – let’s take another example as the tanning of skin. Some people can readily respond by producing the melanin that allows them to tolerate UV and get a suntan and is actually protected. Others, probably some of your buddies from the northern part of the UK may have very fair skin or reddish hair and don’t have quite that same ability. Metabolically some people can induce lactates that allows them to digest milk very rapidly. Others have very low or little ability to [inaudible 00:14:41] significant genetic variation there.

[Damien Blenkinsopp]: Yeah, and here increasingly we have got this biosis when people have problems with their gut, which is pretty common these days. I don’t know if you know a guy called [Chris Cressor 00:14:52]?

[Todd Becker]: Sure.

[Damien Blenkinsopp]: He talks now about using probiotics like kefir but in very small doses to start with, otherwise it kind of overwhelms the gut microbiome. So it seems like he is using some similar principle to hormesis there and with his patients or people who have problems. It has to start very, very small but eventually it gets to a large extent where the gut is able to digest and use it afterwards.

[Todd Becker]: And really that is a good example that sort of also follows the model of what is called oral immunotherapy. It used to be thought that people who had, for example, severe peanut allergies just that there was no hope. They had to take immunosuppressant drugs for the rest of their life and children who were vulnerable to this just had to stay away from even the slightest dust from peanuts in the air. But then there was some really good research that showed that very gradually reintroducing an allergen like peanut under the tongue in extremely minute amounts allowed the immune system to learn to tolerate it to the point where there was no problem anymore. I think that is another good example of that gradual exposure.

[Damien Blenkinsopp]: That is an interesting one because that is where the immune system is overactive in response to a stressor. And then you are teaching it to just be balanced. So it is kind of a slightly different twist to it.

[Todd Becker]: Yeah, well we are talking about allergies and autoimmune disease and I think it is very relevant to point out this recent book that I got very excited about called An Epidemic of Absence by Moises Velasquez-Manoff, and he really updated the hygiene hypothesis, which a lot of people are familiar with which basically holds that allergy and autoimmune disease that has become prevalent in the western world ever since we have instituted a lot of hygiene measures and cleanliness and since people have moved off of farms and paradoxically we have conquered infection, but allergy and autoimmune have gone up. And the idea is that somehow we are not getting exposed to allergens.

But what Manoff does in his book is how is this in terms of the what is called the old friends hypothesis and the idea is that we co-evolved with [inaudible 00:17:07] organisms in our gut, parasites that we lived with basically for evolutionary reasons to outsource some of the functions of our immune systems to those organisms. And that sort of took some of the work away that our own immune systems have to do. But now that we have pretty much banished them through better hygiene we don’t have parasites anymore, our diets have changed so that the microbiome in our guts – we wash ourselves and we don’t have the benefit of the service that they were providing.

So all we are left with is an undertrained immune system with the sort of reserve or the emergency system, the IGV system that just goes crazy whenever it has the slightest insult, and so the idea is let’s reintroduce some of the old friends. But what is particularly interesting in the book is he goes through one autoimmune or allergy disorder after another and shows that there is sort of a critical period in infancy or childhood where if you don’t get that exposure you are prone to these autoimmune disorders.

[Damien Blenkinsopp]: So that is the idea of balance again. It keeps going back to this balance and this is why I wanted you to come on and talk about this, because you have actually tried to identify balance for hormesis using heart rate variability. In my own experience, I have had back injuries and I have had various things where you want to get stronger, you want to recover, and you understand that this concept of hormesis can help you, as you pointed out with your eyesight, right?

But if you push it too far you potentially go backwards rather than forwards. It is the same as like my friend from the university who is going to the gym and pushing it too far and is actually going backwards instead of forwards. And in my training over the years, experimenting with different things, I have often done that as well and figured out that I needed more recovery and I didn’t have this balance.

I have eventually come back to trust numbers. So I thought it was interesting that you were using heart rate variability to look at a little bit and understand if the hormetic effect was having a positive impact or not.

[Todd Becker]: Sure. Now, I know you are a big biomarker guy and you like numbers and I am a little bit more cautious about that. I would certainly like there to be a magic number that I could follow. I have done a little bit of experimentation with a glucose meter, which kind of helped me understand how I responded to diet and exercise in terms of glucose. And I found it a little bit useful but also potentially misleading. I have friends who are sort of in the quantified self movement who measure just about everything and kind of I think go overboard with it But one thing I have seen is that it is very hard to take a single number in isolation because there are always exceptions or what you might be looking at is not a cause but a consequence, so it is difficult.

I stumbled on heart rate variability and what i like about it is it is not just some random measurement of some intermediate metabolite in your body which may reflect oxidation or inflammation but who is to say what the right level is. In the case of heart rate variability you are actually measuring something very close to real function and what I found before finding HRV is to try as much as possible to look at functional measures of strength or performance.

[Damien Blenkinsopp]: Sure, could you give an example?

[Todd Becker]: So the vision is pretty easy, right? You can read a Snellen chart and see when you lift weights and you know how much weight you are lifting. So when you run you can use speed, right? These are very objective things but what I like about HRV, so what do you do in terms of just overall metabolic health? Is there something that sums it up?

[Damien Blenkinsopp]: Why don’t you just take a step back there and clarify? When you were talking about the running and the speed and if it is improving then when you are doing is having a good, positive hormetic effect, right? But if it is going backwards, if you are taking longer times, then you know that you are going backwards – just to clarify for the audience.

[Todd Becker]: Exactly, and there is no question. If you are overtraining and you are running slower, then okay.

[Damien Blenkinsopp]: Right, if you are lifting less weight, which happened to me with many of my experiments back in the days, I would be basically lifting less and you are like, ‘Okay, something is not going right here.’

[Todd Becker]: Right, so if you would like to find something like that for just overall metabolic health, that is a harder one. Maybe you feel good but subjective feelings may not be the whole thing. So what I like about HRV, heart rate variability, is I think it is sometimes not fully understood, what it is. What it is essentially is the variation in the heart beat. You can have a low heart rate but if the heart rate is getting exactly once per second that has got no variability, right?

So why is variability a good thing? And apparently it is. Apparently people who are very fit have a higher heart rate variability, which means there is more variation. Sometimes their heart will be 1.05 seconds and then 0.9 and then 1.03 and then 0.85 and then you look at the standard deviation of that or some transformation of that and the more variation beat to beat there is the better it is. But you would think, why is that good? Because we know of arrhythmias as being signs of pathology and certainly at some level they are.

[Damien Blenkinsopp]: Could you just – what is an arrhythmia?

[Todd Becker]: An arrhythmia would be not having an exactly precise regular beat, having some irregularity to it. And there is different deviations from the regular. So the question is why is it good to have this variability and I was kind of searching for this but I read this book, an older book by James Gleek, called Chaos. It was written in the 80s that in chaos really describes what are called non-linear systems which underlie a lot of what is going on in biology or in the brain and in society.

There are a lot of effects that aren’t just additive but interact with each other in very complex ways. So he had this insight, which is basically non-linear processes are necessary for homeostasis, the ability to handle a stress or a deviation, and come back into control. If you have a linear system and you give it a slight nudge, you cause some [inaudible 00:23:27] to it and it tends to go off course and stay off course. In non-linear systems they have all these interactive components and if you give it a nudge it tends to return to a center, what they call an attractor in mathematical terms. In biological terms, if you have a fever your body acts to cool yourself. If your blood pH drifts there is something that pulls it back. If you eat a big meal and your blood glucose gets too high, the insulin turns on and brings it back within range. So there are these feedback systems that tend to bring you back to center.

So what is interesting is that you have got these two systems which work in cooperation – the parasympathetic and the sympathetic nervous system. And the parasympathetic system is generally the one that kind of calms you down and gives you this resilience where sympathetic is the fight or flight which you need to energize yourself but if it goes too strong it can cause stress, high cortisol and eventually the parasympathetic system has to bring you back down to normal after you have met the stressor, some type of event that you have to deal with. Now, if you are adaptive you can switch between these two systems readily and the key one is the parasympathetic one because the sympathetic one tends to drive, just very strongly and calming down and bring – changing your ability to go at full strength and then slower and adapt to the day is really an adaptive strength. If you look at people who are older and have Parkinson’s and walk very stiff or rigid and you measure their gait or their heart rate it is very regular, very stiff. It doesn’t deviate. If you surprise them, shock them, ask them to suddenly run or something, they have great difficulty shifting into that higher gear and people who are stressed out likewise have great difficulty turning down the stress and shifting. So it is a sign of health to be able to shift gears quickly and be adaptive. And essentially that is what HRV is measuring.

If your heart rate naturally can sort of move around to these different frequencies then it can quickly tune into the faster one or the slower one and it can move quickly. If it is locked into a steady beat it is just harder for it to change and I think this manifests itself in a lot of ways.

[Damien Blenkinsopp]: So you see it as a measure of your ability to adapt to stressors, which is actually similar to some of the other discussions we have had. I don’t know if you have tried this but if you looked at your HRV when you are lying down versus standing up. So in our first episode Andrew Flatt was talking about how standing up is a slight stressor. So you can see how it impacts the HRV and you have a slightly different score and you are basically applying a very, very slight stressor to yourself just by standing.

[Todd Becker]: Yeah, and people even look at how quickly can your HRV when you stand or sit come back to equilibrium. That is sort of a secondary measure and athletes who can run and then sit down and bring their heart rate down quickly are typically the ones who are fit. But if you look at disease states, cardiovascular problems, cancer, infections, these show up very quickly in reduced HRV and it is kind of almost a leading indicator of a problem so it is has even been introduced diagnostically and i think it is pretty powerful. And I find that is useful because we are all individuals as a tool for self-discovery. You can find out what tends to drive your HRV up or down and I learned a lot of things that I was very surprised about myself.

[Damien Blenkinsopp]: Yeah, and like you I have been fascinated by this measure and if you read around it is really applicable to so many useful things as well. I have seen people applying it to willpower and there are studies on willpower and of course we all want more willpower. There are a whole range of uses for this but what have you specifically applied it to and found that was most interesting?

[Todd Becker]: Well, I tried a lot of things relating to exercise and found some of the normal things that athletes find which is that when you work out very intensely it drives the HRV down and it takes a while to come back up. And when it is back up you are rested and ready to go, and that is what everybody knows. But then I just tried different foods and definitely noticed a big effect except the one thing I did notice is that I practice intermittent fasting which means that I eat one or two meals in a part of the day, typically dinner or lunch and dinner, and fast a lot of the rest of the day. And I found that well into the fast my HRV would tend to go up and then after a meal it would go down. So that was kind of interesting.

[Damien Blenkinsopp]: Did you notice an increase in your base line? If we talk about the daily – the specific time you are doing the experiment versus changes which tend to be longer-term?

[Todd Becker]: Oh yes, I definitely have noticed that. So let me get to that after and I will tell you a few specific ones and then I will get into the baseline. So that was a big one and the other really big one which really surprised me is cold showers. So i thought I am going to get in the cold shower and see what happens and I am sure what will happen is my heart rate will go up, which typically means my HRV will go down because it is not precise, but they tend to be inversely correlated, right?

, I am somewhat adapted to the cold showers and I have been doing that for several years. I get in the shower and actually measure it while I am in the shower and my heart rate goes down and my HRV goes up. And I get out of the shower and it has gone up by ten points. And that is kind of the average, it goes up by ten points literally within 3 to 5 minutes and it stays high the whole day, which also corresponds to my subjective feeling that cold showers are a real mood elevator for me, unlike caffeine or sugar or whatever, which is just kind of a quick thing and then it fades. I do that and then I am good for the whole day and it is consistent and it is a big effect. So that was a big positive effect. So fasting and cold showers are kind of the two things that really drive it up.

[Damien Blenkinsopp]: So the cold there is a cold exposure, basically, so it is a minor cold – ?

[Todd Becker]: Yes, cold exposure. So I get in a pretty cold shower and I am in there for several minutes. I used to, when I started that, I would shiver quite a bit. But that only lasts a little bit.

[Damien Blenkinsopp]: So, that’s a pretty cold shower?

[Todd Becker]: Yeah, and I do ocean swimming and things like that which is really fun. But then I found some negatives and of course I found that if I worked out really intensely, I could drive my HRV down really low, which worried me. But it would come back as hot tubs that are really hot that would also drive it down. The other thing that would really drive it down was alcohol. Usually it would be maybe two or three drinks and one drink didn’t have much effect but two or three drinks would really drive it down.

[Damien Blenkinsopp]: Is this like for a few hours, say for the rest of the day?

[Todd Becker]: A few hours or the evening. And then I thought about this and this was really interesting. I thought, wow. The cold showers surprised me because I thought that was definitely going to get my heart rate up and it didn’t. And alcohol, that will make me relax so my heart rate will slow and my HRV will go up, right? No. My heart rate goes up and basically the body is trying to deal with the alcohol. It is a depressant so it is trying to fight that and you are impairing yourself and I think this was a real insight because what is HRV? It is your resilience, your ability to take on the next stress and you may think that if you have had a few beers that you can handle things but actually you handle them a lot more poorly. Driving, of course, is an example but your judgement goes way down.

[Damien Blenkinsopp]: Yeah, that is very interesting. You see a lot of fights with alcohol, for example. And that is because people are not able to adapt to them and they are overreacting and not able to deal with emotional stressors around them.

[Todd Becker]: Yeah, the adjustment goes way off. So basically these things that are kind of relaxing can impair HRV and then things that are stimulating, the cold shower or fasting, which also tends to sharpen your focus and help the HRV. Then the other effect is – these are the immediate effects.

[Damien Blenkinsopp]: So just going back to the heat exposure, I do saunas, infrared saunas, and I have been doing that daily for the heat shock protein benefits, amongst others. I don’t know if you have done that and unfortunately I am going to have to track the HRV specifically around that and I am going to have to start doing that to see what happens. Do you think that would be similar to the hot bath?

[Todd Becker]: I think so, but here is the other half of the story because these are the immediate effects, right? The things that you notice within hours or minutes, but then you have got to look at the compensatory effect of what happens later. So for example exercise obviously impairs your fitness temporarily but you wouldn’t do it if – one of the reasons you do it is to become stronger and get fitter. So you do it and then the next day your HRV is actually a little bit higher. It may take two days or whatever the recovery period is so there is almost this ratcheting effect where you temporarily drive it down and then it kind of comes back up to an even higher level and I think that is pretty interesting. So the question is which things work that way and which things are just direct? So the cold showers brings the HRV up and then I don’t see a fading of that. Exercise I see it going down and then it comes up stronger and I think hot tubs and saunas are a little that way where it drives it down, but I think it actually can improve.

[Damien Blenkinsopp]: Do you think this could be in relation to the way your body perceives the intensity of the stressor? Maybe heat is a larger stressor than cold so your cold shower just happens that it is at the right balance?

[Todd Becker]: It may be and also heat on some level relaxing and another level is a stressor, so it may be the degree. And it is similar with alcohol. Moderate alcohol didn’t have the same effect as –

[Damien Blenkinsopp]: Yeah, so if you had like a tiny sip of alcohol potentially your HRV could have risen a little bit?

[Todd Becker]: A little bit more. So let’s go to the baseline question. So I have actually increased my baseline HRV over a couple of months significantly and there is a lot of noise and fluctuation if you look at my graft but what I did is I am careful not to overtrain and I noticed that can really set me back. Then with alcohol I have realized that one or two drinks, I feel the buzz. It is social, it is fine. And I really cut myself off there and I drink less. And that has really helped the HRV come up quite a bit. So I am just kind of paying attention to the things that really set me back and that is probably the main change and then it has come up about ten points.

[Damien Blenkinsopp]: Yeah, so I mean it is important to point out also that as you age it gets lower, so that is another reason you kind of want the baseline to be going up rather than going down. As you said earlier it is an indicator of general health but as age also so you could say biological aging. So I have noticed with intermittent fasting that is the one where I have been looking at it the most and I have done – I did one month on intermittent fasting and then two weeks off and then back to intermittent fasting again. and I am about ten points higher pretty much every day. It takes a little bit, a little while to climb back up to where it was if I stop intermittent fasting. But after about a week it tends to be about ten points higher than when I am not intermittent fasting, so that is about three months of data so far. But for me it seems – and I feel, of course – I mean, a lot of people talk about the benefits of intermittent fasting but I feel much better and much more energy throughout the day and so on.

[Todd Becker]: One thing I did that really drove it up and of course you can’t do this all the time, I took a vacation. And it went way up. Obviously, that was useful.

[Damien Blenkinsopp]: Yeah, that is a really important point you bring out here because especially you are from the US and very well known for having not taken any holiday or you have your standard two weeks, I believe, in the US?

[Todd Becker]: Right.

[Damien Blenkinsopp]: But of course, many people work in corporate and if they are not taking their holidays at all. You see a big increase in HRV like that and that is a really big sign that you are probably really overdoing it and you need to emphasize more some time out. I don’t know if you thought of it that way, when you saw those numbers, maybe I should do this more often?

[Todd Becker]: Sure, I tend to lead a life that even though it is busy I don’t feel stressed out and I really feel in balance. So I wasn’t feeling overworked but of course maybe I was fooling myself.

[Damien Blenkinsopp]: I mean, this is the beauty of trying to quantify stuff because I will give you an example. My dad, he is a workaholic and he always has been. And so he doesn’t – when he goes on holiday he falls asleep. And my impression is that he is highly strung. So he is working and I feel the same way when I am working and I have often had the case where I am working hard and then I will take a holiday and I will get sick when I am on holiday. And it is kind of like your body is just trying to manage the day to day and why you are stressed is just dealing with it. But as soon as it has an opportunity to let go. It would be like okay, you can recover now and I can be a bit sick.

[Todd Becker]: Isn’t that true? That is a common effect, you finish your exams and you come home and you get a flip, right? But my vacations tend to be somewhat active with cycling, body surfing, running, and so I wasn’t just sitting on the couch all day either but I was really enjoying myself and that was the key.

[Damien Blenkinsopp]: Great, some great insights there. Have you found any other areas with HRV as being useful besides these we have already spoken about?

[Todd Becker]: There is Dave Asprey who has written something and he has a little company and an app he has created to use HRV to detect food sensitivities.

[Damien Blenkinsopp]: Yes, they are actually using heart rate. We actually had Rhonda Collier on the last episode. She is the CEO of Sweetwater, who is behind that app.

[Todd Becker]: Exactly.

[Damien Blenkinsopp]: That one is based on pulse rate but she does some very interesting stuff on the stress side, splitting out the frequencies. And I haven’t played around with the app a lot on the stress side, but I think you have to get into it quite a bit to find some benefits. She certainly has over time, but she has been using it for a very long time.

So coming back to the whole hormesis side, I don’t know if there are any other biomarkers besides HRV? You have mentioned the difficulties of trying to assess, basically saying how much oxidative stress do you need versus not? It is very hard to say what is going to be beneficial versus what is going to be overwhelming for your body, which is why you are looking at the endpoint, the end result?

[Todd Becker]: Yeah, the functional endpoint and what really matters in terms of performance.

[Damien Blenkinsopp]: So obviously you brought up some others which are more specific to whatever you are doing, how fast you are running and so on. Is there anything else you have come across that you have found useful for looking at hormesis and how to balance it?

[Todd Becker]: Not in terms of quantitative measures. I think in this discussion we have really focused a lot on the physical side of hormesis but I think it applies quite well also to psychology and to sort of the spiritual side of health because really what is stress? There are physical stresses but what we are really talking about is your reaction to events, right? And so how you handle stress I think is very important to health and there is this concept out there that we are overstressed, that modern life causes not just physical but psychological ailments because of too much stress.

I think what they are talking about there is chronic, repetitive, daily stress that we are not handling well but I think the underappreciated side of stress is that we need it and particularly we need it at certain frequency and certain natural contexts and we need intense stress. Our body, we evolved to be able to handle it and if we protect yourself from psychological stress we actually become more vulnerable to it. I think that exposing yourself to intense physical exercise actually makes you more psychologically resilient but I think it is also important to confront fears, anxieties, and push yourself to higher levels and also to become comfortable with discomfort just in general. In fact, it is even sort of a psychological benefit to things like cold showers and that you are throwing yourself into what you perceive to be an intensely uncontrollable, disagreeable situation and you are pushing through it and you develop more resilience to it.

[Damien Blenkinsopp]: Right, because you talked about this on your blog and I started doing the cold showers, as I mentioned to you. And you say that you are tensing your muscles and you are psychologically preparing yourself for it and it is quite a horrible shock when you start but later on you start really noticing it. I mean, I found this after a few weeks or something and I guess that is what you found over time. Do you still find that you react a little bit to the shock of the cold?

[Todd Becker]: Yeah, and it is less and less. And there is this theory called the component process theory of emotion that Solomon and others sort of pioneered and Solomon was looking at – he was trying to explain addiction and also thrill seeking and he said these are really sort of the opposite sides of the point. A thrill seeker is somebody who does skydiving and the first time they do it they are confronted with this intense, paralyzing fear. It is uncomfortable. But when they land there is this euphoric afterglow that tends to last for a lot of the day. But the more they do it the event itself becomes less and less uncomfortable and the afterglow effect becomes stronger and stronger so it becomes pleasurable.

Cold showers, it is a little bit like that. Exercise can be like that. And you said it is the flip side of addiction. In addiction people pursue a direct pleasure, whether it is alcohol, drugs, sex, gambling – whatever it is, it gets their dopamine going right away. But then when they stop it there is this down or withdrawal. So this is the reverse to where the more they do it they become tolerant to the pleasure and it is less fun but the down becomes greater, so they get into this addictive cycle because they just need to do the addictive activity just to get back to normal.

So exposing yourself to hormetic stress is kind of the opposite of addiction and what I find is that it makes you more resilient to just daily stressors, arguments and things that come up at work and it increases what I call my background level of pleasure. I mean, I am just basically always happy and things don’t throw me off or blow me out and I think it is because by forcing yourself to expose to these intense stresses, you develop this resilience. It is something that has kind of gone away from the kind of lives that people, pioneers who lived away from civilization, had to face these natural stressors – the weather, hardship, lack of food, moving around. And the fact that we are more protective and that we live in an environment that is so regulated from stress I think we failed to develop this resilience. And so by engaging in some of these activities I think you get an enormous psychological benefit in addition to the purely physical.

[Damien Blenkinsopp]: Right, so that is a great overview. Basically the way you are using hormesis is if you can do this in lots of different aspects of your life then they are all kind of tied into your organism and HRV is like an endpoint measure which is global, so it is useful because it is like if my HRV is higher today I am going to be more resilient to emotional stress. No matter what it is if I have to be motivated to do something or take on a new challenging task like if I got higher HRV some days then it is probably going to be an easier day to start something new.

I have been looking at that a bit because I have heard about this, but I don’t know if you have – when you notice that your HRV is high if you find it easier to start more challenging tasks or take on conflicts or these kind of more mental challenges and I don’t know if you have noticed anything about that?

[Todd Becker]: Definitely, and I think that is the case.

[Damien Blenkinsopp]: Great, so what you are doing in terms of your routine and where you use biomarkers or you don’t, you have already talked a little bit about where you have seen them be useful or not, but on a week-to-week basis what kind of things are you tracking in your life?

[Todd Becker]: Quantitative things?

[Damien Blenkinsopp]: Right, whether it be HRV – what is kind of your routine for using any type of data about your health?

[Todd Becker]: I would love for there to be an app that really gave me information that I found useful and used all the time. And I understand companies like Apple are kind of moving into that space. And there are a lot of devices out there. So I am always interested in them but I just haven’t been convinced in their utility. And I am also a little bit hesitant to become too tied to tracking. I want to be much more tuned to my actual experience and try to find ways to use that as much as possible. I am a bit of an advocate also of simple finds, like relying as little as possible on external things, whether they be glasses or supplements or devices so that I can be fully present.

But if I can find a few things to track and if they are pretty robust I will go for them. So HRV is probably – I mean, I was experimenting with a glucose monitor and that was helping a little bit but I didn’t find it necessarily reliable. So the HRV is maybe the closest I have found so far, although I don’t know if I am at a level where I fully trust it yet. So I don’t know if there is any you find particularly useful?

[Damien Blenkinsopp]: Yeah, I track a lot of stuff and I kind of bring new ones in and then throw them out as they become inconvenient. Also one of the biggest challenges I think right now is the convenience. If we had a watch or some device which tracked everything accurately in the background it would be really easy to have interesting data. But on the HRV I use the averages, seven-day rolling averages, because it does go up a little bit and down. There is a little bit of variance in it and also just in the way you are measuring it you can introduce little differences based on emotional stress and other aspects so you have to watch out a little bit for that. So I find that I am really watching more closely the seven-day rolling average.

[Todd Becker]: I tend to agree. I think the weekly average is just about right and that seems to correspond to something that I see as a real shift.

[Damien Blenkinsopp]: Yeah, and I feel remarkably different when I am ten points higher on that average, so that is what I am trying to do, get it as high as possible. So just out of interest, I don’t know if you are lying down or you are standing up, what HRV score are you?

[Todd Becker]: Yeah, so I do it sitting and I am using the RMSSD, the natural log times 20, so on that scale I am typically in the range of in the morning 70 to 80. And on really good days I have actually hit 90, which doesn’t happen very often. And on sort of off days I might be in the 60s. But I would say kind of typically bouncing around between 70 and 80.

[Damien Blenkinsopp]: Right, you are a bit better than me. don’t get up to the 90s. My high is at the 80s. I am normally between 70 and 80 when I am intermittent fasting. Otherwise I can be between 60 and 75, maybe a little bit lower at 60 to 70 and it will go as low as the 50s on bad days. But I am actually dealing with some health issues so I think that is responsible for that mess.

[Todd Becker]: Certainly. I wouldn’t consider myself an athlete, I would just sort of consider myself generally fit for being 58 years old. So to me as long as it is sort of in that range I am happy and as an indicator that it is sort of a warning sign if it were to plunge, I start to look into it.

[Damien Blenkinsopp]: When mine plunges I take the day off. I have had some really crazy crashes and sometimes I don’t know what is going on and you have got a virus or something. I got a crazy flu virus from my nephew just recently and it took me out for a week. But I knew about it the day it was hitting because of the HRV. Even if I felt not so bad in the morning, the HRV showed it beforehand.

[Todd Becker]: Yeah, I think you’re right – fatigue, infection, and it picks those things up right away. And intoxication.

[Damien Blenkinsopp]: Alcoholic intoxication. Well Todd, thank you so much for your insights today about hormesis, which is really very a broad and interesting framework to look at all sorts of things we could be doing to improve our bodies in terms of performance and so on, and your experience with HRV has been very interesting to hear.

[Todd Becker]: Well, I have enjoyed talking to you. Thanks for the opportunity.

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In the first episode of The Quantified Body, we looked at the biometric of Heart Rate Variability or HRV and how to apply it to optimize training and workouts.

HRV has also been researched in other contexts such as stress management, general health, motivation, and willpower, where it can help you make decisions about how to improve these areas and identify what’s working for you – and what is not. So we’re going to continue to look at its use in these different contexts and the research behind it.

Today we’re looking at managing stress with heart rate variability and general health management, also our guest heads up the company which is currently leading the way in HRV apps targeting the stress management area.

Today’s guest is Ronda Collier, CEO of SweetWater Health, a company developing HRV applications for mobile platforms like the iPhone and Android. Ronda has over 25 years experience in technology product development and founded SweetWater Health in 2010 to focus on Heart Rate Variability.

She’s very hands on and working with a variety of companies in the area, so there’s a lot of practical details in our chat today and ideas from her on how HRV apps are going to progress over time.

The show notes, biomarkers, and links to the apps and devices and everything else mentioned are below. Enjoy the show and let me know what you think in the comments!

itunes quantified body

Show Notes

  • A review of the market of heart rate variability supporting devices and apps and the different standards and their accuracy.
  • What is required for accurate readings in terms of data input from the EKG compliance heart rate reading device (e.g. heart rate chest strap, ).
  • The best “use cases” Ronda has found for getting actionable data from heart rate variability.
  • The different measures of HRV: Time domain, frequency domain and non-linear.
  • Using HRV for stress management, to improve your stress baseline with activities like meditation and see the progress as well as identifying ‘high stress’ triggers for you.
  • Comparing the HeartMath coherence training to the use of the standard HRV stress measure (frequency domain).
  • How to use the SweetBeat and SweetBeat Life apps to monitor stress – some tips on Ronda on how to use effectively including health and less healthy (aka chronically stressed) benchmarks for HRV, LF and HF to compare your numbers to.
  • How the more advanced users are using the SweetBeat app and its more detailed metrics and functionality to improve their stress management over the day.
  • Other functionality on the SweetBeat and SweetBeat Life apps including food allergy/ sensitivity testing and correlating changes in a range of biometrics tracked by the app including HRV and other readings from devices it interfaces with.
  • Using HRV as an objective measure of effectiveness of alternative health treatments or techniques such as acupuncture or chiropractor.
  • The goal of raising your parasympathetic activity (HF) to lower chronic stress and the interventions and activities that have an impact on it such as yoga – Ronda provides benchmarks and examples of what they’ve seen work.

Give some love to Ronda on Twitter to thank her for the advice in this interview.
Click Here to let her know you enjoyed the show!

Biomarkers in this Episode

  • Heart Rate Variability (HRV): Measures how your heart rate varies over time. Research studies link HRV to recovery status, stress and other aspects of human physiology. See the specific measures below for which ones measure stress.
  • R-R intervals: Time interval in between heart beats (R = peak of heart beat).
  • RMSSD (Root Mean Square of the Successive Differences): The time-domain measure used to calculate HRV that has proven to be reliable and is used in a lot of the research studies – the industry standard for HRV.
  • lnRMSSDx20 (RMSSD with natural log and multiple of 20 applied): Applications have begun using this measure, which is basically RMSSD scaled to an index of 100, to make it more user friendly. SweetWater uses their own version of this.
  • LF (Low Frequency): Spectral measure that indicates combination of parasympathetic and sympathetic activation. The HeartMath algorithm uses a spike at a frequency within this band.
  • HF (High Frequency): Spectral measure that indicates parasympathetic activation.
  • LF/HF Ratio: The ratio of LF to HF gives a proxy measure of stress, or more specifically .
  • HeartMath Coherence Score: The HeartMath coherence score goes from 1 to 16 and measures your alignment with a spike at 0.1Hz on the frequency domain which is within the LF zone, and none or very low presentation in the other areas like the HF zone. LF represents both sympathetic and parasympathetic activity, so the 0.1Hz frequency is related to parasympathetic activity specifically. You find this within HeartMath
  • Resting Heart Rate (RHR): Measure of your heart rate at rest (typically measured upon waking). This is one of the measures Ronda tracks routinely to monitor her own health.
  • Blood Pressure: One of the biometrics that Ronda tracks for her own personal health.
  • The Coca Pulse Test: A measure of increase of heart rate that attempts to identify food sensitivities and allergies. You can read more about it in this book from the creator Dr. Arthur Coca, The Pulse Test: The Secret of Building Your Basic Health. SweetBeat and SweetBeat Life HRV apps use this test for their food sensitivity functionality.

Apps and Devices from this Episode

  • SweetBeat: The original HRV app that has been available for the last 2 years – it has HRV for training, HRV stress, food sensitivity functionality.
  • SweetBeat Life: Ronda’s new app that has extended functionality including the correlation function and additional data on HRV and real time HRV data.
  • Ithlete: One of the competing HRV apps with similar functionality to SweetBeat in the HRV for training area. Does not have HRV stress management functionality.
  • The Health Patch: One of the competing HRV apps with similar functionality to SweetBeat in the HRV for training area. Does not have HRV stress management functionality.
  • HeartMath: HeartMath use a proprietary algorithm measuring coherence with a variety of devices including the emwave2 and Inner Balance Sensor (iPhone, android).
  • Basis Watch: Watch that tracks heart rate and resting heart rate, but due its technology, has limitations in accuracy and sampling and is unable to record heart rate variability.
  • Mio Alpha: Another watch with heart rate monitor functionality which is working on a more advanced technology than the Basis watch, which may potentially track HRV eventually.
  • Bioforce HRV: Another application used for HRV for training similar to ithlete.
  • VitalConnect HealthPatch: A stick on patch that lasts for a number of days or longer depending on use that tracks heart rate and heart rate variability. The SweetBeat apps work with this patch and SweetBeat Life can use the data with its correlation functionality.
  • Withings WS-50 Smart Body Analyzer: This device weighs you and tracks other body data. SweetBeat Life interfaces with this and is able to use the data with its correlation functionality.

Other Resources Mentioned in this Episode

    Ronda Collier and Sweetwater Health

  • Connecting with Ronda Collier and SweetWater Health: You can connect with Ronda at her website SweetWaterHRV.com (company site) and also on twitter @BeatHealthy and facebook BeatHealthy.
  • Other People, Resources and Books Mentioned

  • Quantified Body Ep. #1 on “HRV for Training”: In this previous episode we looked at using HRV to optimize workouts and training sessions in great detail with Andrew Flatt, athlete and researcher.
  • The Quantified Self Conference: This conference takes place yearly in San Francisco and has many devices and apps companies attending as well as many presentations on quantified N=1 experiments and on the quantified self movement itself.

Who should I interview next? Please let me know by clicking here

Full Interview Transcript

Transcript - Click Here to Read

[Damien Blenkinsopp]: Hi Ronda, great to have you on the podcast.

[Ronda Collier]: Hi Damien, thanks for having me.

[Damien Blenkinsopp]: That’s great. I did see you briefly last year in the Quantified Self. Do you go to that conference every year?

[Ronda Collier]: Yeah, we have been the last – well, there have only been two and we have been at both of them. We presented at breakout sessions for heart rate variability. So they are pretty popular.

[Damien Blenkinsopp]: Yeah, and do you meet a lot of providers of HRV? You have been in this segment since 2011. How has it changed since then? How many players were there doing HRV stuff back then and how has it changed now? Are there different types of players? I noticed your proposition is changing a bit.

[Ronda Collier]: Yeah, back in the old days and really before smart phones, heart rate variability systems were big and clunky and expensive if you wanted to measure some of the standard HRV values like LFHV, which we can talk about. And nobody really heard of them quite frankly. I only know because that is our space. I think Heartmath really brought heart rate variability closer to the consumer with their M-wave products.

[Damien Blenkinsopp]: So they were the first ones, although theirs is actually a bit different to the standard.

[Ronda Collier]: Yeah, theirs is different and Heartmath is really more about coherence training, which is wonderful in itself, but they really had people talking about it in some of the more esoteric books, if you will. But I ran across Heartmath in reading some books for actually researching my thesis.

[Damien Blenkinsopp]: So how long has Heartmath been around? I know you worked there for a little while.

[Ronda Collier]: Yeah, they have been around about 20 years, yeah, for a long time. So they have an extensive amount of research on heart rate variability that is pretty interesting. And then three years ago you had iFleet starting to come out and that was really it. And then you have Zumio came out with their camera sensor, which is not very accurate but yet sort of furthering the cause of heart rate variability, which is important.

And moving all the way up until today where we are seeing a few more players like iFleet more in that space, Bioforce really not displaying all the HRV parameters like Sweetwater is, more the number used for training.

But I think the big news in heart rate variability is the Samsung, the new Galaxy is announced to measure heart rate variability.

[Damien Blenkinsopp]: Wow, yeah, that’s a big deal.

[Ronda Collier]: And even though it is just with the camera sensor, just for your listeners, a camera sensor is never going to be accurate.

[Damien Blenkinsopp]: Right, that is something I wanted to talk about today because I know you plug in with a variety of sensors. We did talk in our first episode with Andrew Flatt about some different sensors and some of the different measures and obviously we want to make sure people understand the practicalities and the accuracy, depending on which one they decide to go with. I think that is an important point.

[Ronda Collier]: It is – and so even though the Samsung is using the camera sensor, they are talking about it. And now that is great, and it means it is showing up in the mainstream. So we are really excited. It is such an important parameter that has just been kept in the closet for some reason.

[Damien Blenkinsopp]: Right, so let’s just kind of dive into the kind of accuracy since we are talking about it anyway and we won’t have to circle back. Obviously the thing about the Samsung Galaxy is they didn’t want to provide something external to the phone, and they want to try to have the device within the phone. And besides the camera sensor, is there anything else you could use that would actually come with the phone that would be able to help you track heart rate?

[Ronda Collier]: The closest idea I can come up with for you here is there is a company called AliveCore that has an iPhone and Android case, and it is actually EKG accurate, which is what you really need for accurate heart rate variability and that is all that Sweetwater will support, anything that is close to EKG accurate.

[Damien Blenkinsopp]: How do you establish that standard, EKG accurate? Is there a certain – I don’t know, is there sensitivity in terms of the speed of the heartbeat it has to be able to pick up? Or how do you rate that?

[Ronda Collier]: There is obviously the sampling rate. It has to be twice the heart beat. It is called Nyquist frequency for electrical engineers. But really what you need in simple terms are accurate, beat-to-beat intervals.

[Damien Blenkinsopp]: So you are saying that it has to sample twice as fast as whatever heart rate you are trying to –

[Ronda Collier]: At a minimum, yeah. There is something called the Nyquist frequency in electrical engineering, so if you want to get an accurate digital sample it has to be at least twice the frequency of what you are sampling.

[Damien Blenkinsopp]: Right, and for the normal population what is the maximum heart rate you are trying to track?

[Ronda Collier]: Oh we track, gosh, as low as 30. And if you are below that you are pretty sick and you probably aren’t using our product. Then up to about 200.

[Damien Blenkinsopp]: 200, wow. So you have to be running?

[Ronda Collier]: Some athletes actually get up close to that. My personal max heart rate is about 170, but people do get up in the 200s and we can measure that as well. So you have a wide range. But really it is getting accurate, beat-to-beat intervals that is the most important.

[Damien Blenkinsopp]: Yeah, does that mean with all of the different sensors you work with – because you have the application which interprets the data, and you work with a bunch of sensors from different providers, quite a few companies. Do you only work with providers which have the specification you just gave us? Do all of them fit that?

[Ronda Collier]: That’s right, that’s right. We support lots of shelf chest straps, like a Polar or a Zephyr, and there are a lot of Bluetooth heart rate monitors out there now, but now all of them work with Sweetwater. Some of them simply don’t transmit our intervals at all, and that is the beat-to-beat interval. So when I refer to R-R, that means the beat-to-beat intervals.

[Damien Blenkinsopp]: Right, so you are saying that some of them only track the heart rate and they don’t track the difference?

[Ronda Collier]: That’s right. And then some transmit the R-R intervals, but they are not accurate.

[Damien Blenkinsopp]: Could you give us examples of that? Is it because they are dedicated to a different application? Why is that?

[Ronda Collier]: I think that a lot of the vendors are starting to realize they want to transmit R-R intervals, but they just haven’t spent the time on it yet I would imagine, because we have worked with several vendors who did not have accurate R-R intervals and then worked with us to get there. Their focus was to get the Bluetooth heart rate monitor out first with an accurate heart rate and the R-R intervals were a secondary item. Then once they worked with us they got those to be accurate.

So that is usually the vendor is not interested in the R-R interval or they are interested in getting them accurate.

[Damien Blenkinsopp]: Right, and you think this is something that is changing, whereas people were just kind of focused on heart rate a few years ago, or three or four years ago, so these censors came out which didn’t look at the R-R now. Now would say most of them have this on their agenda in some way? Or is it still –

[Ronda Collier]: Yeah, I would say so. There are a lot of off brands that we haven’t even heard of, much less tested, that our customers are finding and then emailing us saying that their HRV doesn’t look correct. So we go and usually write the vendor and ask them before we go purchase the item.

But yeah, there are a lot and I am really surprised at the number of small companies doing the Bluetooth, low-energy heart rate monitors.

[Damien Blenkinsopp]: I guess that technology is relatively cheap, so there are a lot of chest straps and things like this that have come out. They haven’t necessarily done the full technical specification?

[Ronda Collier]: That’s right. So anyone that is going to use a heart rate variability app such as Sweetbeat or Sweetbeat Life, I recommend going to our website and selecting one of those, because we have tested those and we have actually measured that the R-R intervals are close to being correct.

[Damien Blenkinsopp]: So I guess the lesson here is there is no specific industry standard used by everyone. So if you were going to get something like Sweetbeat you should definitely go to your website, like you say, and check which ones are relevant – and it is probably going to be like that for a while, I guess?

[Ronda Collier]: Yeah, yes. Even the ones that look like they are working, we do a detailed test. We are all engineers at Sweetwater – the founders are all three electrical engineers so we are very careful about making sure that one plus one equals two. So what we will do is say a three-minute Sweetbeat session and then we will dump the R-R intervals, and they better add up to three minutes.

[Damien Blenkinsopp]: Okay, and yours is always three minutes?

[Ronda Collier]: For the HRV reading, yes, that is for the athletic reading. But you can do five minutes or eight minutes, but the R-R intervals need to add up. And some of the heart rate monitors don’t and so we work with the vendors to try to get that more accurate, because we want to support them.

[Damien Blenkinsopp]: Yeah, and it is better for everyone if you can support more sensors. So there are a bunch of different things coming out. There are the chest straps, which we have spoken about – so you are working with Polar, 60Beat, Zephyr, and Wahoo. And then there are biosensors, where you have these plastics that stick to you, basically?

[Ronda Collier]: Yeah, we just released our second product called Sweetbeat Life, and Sweetbeat Life works with what is called the health patch, which is a product by Vital Connect. So the health patch looks like a big band-aid, about three inches long, and that is an FDA-approved, single-lead EKG. It also measures respiration, body temperature, body surface temperature, calories burned – accurate, by the way, because it is measuring your body temperature and heart rate – as well as activity.

It is a real doozy, it has got everything in one. We are really excited about that because we are going to get a whole bunch of new metrics and be able to correlate that with heart rate variability and stress and provide more information.

[Damien Blenkinsopp]: That is great. How long does someone wear a patch like that for? How long does it work for?

[Ronda Collier]: That is a great question because we came up with a use model that Vital Connect never considered. Their original use model was it comes with a separate module, the patches are disposable and so you plug the module in and stick it on and their use model was you could wear it for three days until the battery dies.

[Damien Blenkinsopp]: It’s 24 hours?

[Ronda Collier]: You can, yeah, if that is what you want to do. What we do is we just keep the plastic that goes on the back and rather than have to put a chest strap on in the morning when you are doing your morning HRV reading you actually reach over and grab your patch, stick your module in, and stick it on. And so I get the patch to last for over a month.

[Damien Blenkinsopp]: You basically have this sticky part on you and then you just plug the electric part in every morning?

[Ronda Collier]: I peel the band-aid off, like take the band-aid off, and you pull the module out to save the battery, and I just have that sitting by my bedside. And in the morning I grab the band-aid and I stick the module back in and stick it back on.

[Damien Blenkinsopp]: Oh, so it sticks on and off without a problem, basically?

[Ronda Collier]: It does, and it is funny – different skin types can do it more than others. But if you are laying flat on the bed for your HRV morning reading it works pretty well for like a month.

[Damien Blenkinsopp]: You said two interesting things there. The first was you said FDA-approved for EKG. So does the FDA approve certain monitors and sensors and say they are EKG standard?

[Ronda Collier]: You go through a process, basically, to get a device clearance. But yeah, so this particular one is FDA approved. And for over-the-counter, obviously, because we are selling it to consumers.

[Damien Blenkinsopp]: Do all of them have to be FDA approved?

[Ronda Collier]: No, this is a consumer product. Although we – our product is we want to have values that are clinical grade and we do tests to make sure they are accurate. And I do want to note that HRV is very sensitive to the data going in. So if you have the wrong R-R intervals or the wrong interbeat intervals you are not going to get accurate data. So it is super sensitive. So anyone who is interested in HRV, make sure that you are aware that you have a quality heart rate monitor, whatever that is.

[Damien Blenkinsopp]: Definitely, and I want to talk more about the accuracy and use cases. The other interesting thing that you said though was you are using it and it sounds like you are using the HRV for training in the morning. Is that your main use for it? How else do you use it yourself?

[Ronda Collier]: Well, I use it for HRV for training in the morning. I also use it to track my circadian rhythm. I am really curious what is going on with me, quite frankly, at naptime in the afternoon. And it is very interesting – my parasympathetic nervous system actually increases in the afternoon?

[Damien Blenkinsopp]: Is that because you have a nap?

[Ronda Collier]: Yes, I will back up. Heart rate variability has a circadian rhythm, and I look to be curious, to see what is going on. And sure enough at 2:30 in the afternoon my parasympathetic or HF, HRV parameter increases.

I also use it especially early on with Sweetbeat. I used it when I was sitting at my desk to figure out what was going on and why I would get triggered. Because you are working all day and suddenly your neck hurts. And you are like, ‘What was I doing?’ You don’t even know because we do it all the time.

So I have actually learned that if a browser doesn’t load when I think it should, my face gets in the screen and I tense up.

[Damien Blenkinsopp]: You told me about this at Quantified Self. I think everybody hates that and we just don’t really realize how much.

[Ronda Collier]: Well, the important point here is that if you can learn one thing that you are doing all the time, then you can reduce your stress.

[Damien Blenkinsopp]: Yeah, and is that an HRV reading? You are using the stress monitor with your HRV app for that?

[Ronda Collier]: Right, right.

[Damien Blenkinsopp]: Okay, and previously we have talked a bit about HRV for training, so I think the audience has a reasonable grip of that and then how that works. And we didn’t look at all on the stress side, and that is a different calculation. Can you talk a little bit about what is behind that? How does it use HRV and how is it different with HRV for training calculation?

[Ronda Collier]: Yeah, absolutely, so the HRV for training calculation is based on – let me back up because I think it is better to give a high level of review. Heart rate variability, in itself, is just that – the variation of the heartbeats in the beat-to-beat intervals. It can be measured in several different ways. One is called time domain, or statistical analysis, like standard deviation. Root mean square of successive differences. The RMS, those are all typical statistical measures.

Then there is another way to measure the HRV and that is called frequency domain. And this is using [inaudible 00:16:43] fast forms and for you engineers out there, you kind of know what that is. And looking at the frequency components of the R-R intervals.

And then thirdly there is actually non-linear, which we are not using in Sweetbeat at this time. So the HRV for training uses a time domain parameter called RMSSD and that is a measure, it turns out, of your vagal tone. And the vagus nerve is the tenth of 12 cranial nerves in the nervous system, in the [inaudible 00:17:12] nervous system. And that particular piece of the nervous system is what gets fatigued during overtraining and endurance sports. So we measure that time domain measure for the HRV for training.

[Damien Blenkinsopp]: And you were saying that you specifically use that because the research has been based mostly on that measure?

[Ronda Collier]: Yes, that’s right.

[Damien Blenkinsopp]: So just one clarification on that – when you have actual score in Sweetbeat, the last time I spoke to you, you said it was based on 100. Is that the natural log of RMSSD times 20, or are you using something different? I think iFleet uses the natural log times 20.

[Ronda Collier]: Yeah, it is similar to iFleet but it is not the same.

[Damien Blenkinsopp]: So if you went out and got one and then a month later it broke or whatever and you went and got a different one, then you can’t have all of those values in Excel and compare it back for two months because they don’t necessarily fit?

[Ronda Collier]: No, no. And that’s actually a great point, Damien, because we have had people ask why is it different in iFleet? Because we use a different algorithm. We were 10,000 miles apart, having the same idea, but doing it differently.

[Damien Blenkinsopp]: So there is no industry standard, and it is basically because everyone decided it was going to be better to have it on a roughly 1 to 100 rating?

[Ronda Collier]: Yeah, it is a consumer thing. But there is an industry standard for HRV, but it is in numbers that a consumer would have a hard time with.

[Damien Blenkinsopp]: Could you give us a quick example?

[Ronda Collier]: Sure, so RMSSD, depending on who you are and HRV is very individual – while you sit there and in three minutes it can go between let’s say 60 and 68 – and it will sit there and vary because your nervous system is very dynamic. And then maybe the next day you get up and it is 54. So these numbers are just not easy for people to deal with.

So by scaling it from 0 to 100 it is easier for people to understand.

[Damien Blenkinsopp]: Yeah, that makes sense.

[Ronda Collier]: The stress level, so that is the HRV for training piece. And then the stress level, we actually use the frequency calculations of HRV and we measure the low-frequency components, which correspond, in simple terms, to the sympathetic nervous system. Actually, it is a combination of sympathetic and parasympathetic, but mostly sympathetic-dominant.

And then the high-frequency components, which are a measure of your parasympathetic branch of your autonomic nervous system. So for the stress level we look at those two and then we measure the balance between the two. So when you are sympathetic-dominant, you are stressed, sympathetic or fight-or-flight dominant, you are stressed. You want to actually be sympathetic-parasympathetic balanced.

But when you are really relaxing or just woke up in the morning and are sort of chilling, then you actually want to see yourself being a bit parasympathetic-dominant.

[Damien Blenkinsopp]: So if you are at work you would want to be a little bit sympathetic-dominant? So you are working on something and you are writing or doing a presentation?

[Ronda Collier]: Yeah, you normally would be. But you don’t want to be chronically that way.

[Damien Blenkinsopp]: Okay, so you are saying that balance would be 1-1, so LF and HF would be equal?

[Ronda Collier]: Yes.

[Damien Blenkinsopp]: What is bad? What kind of ratio is starting to look bad? Is it 2-1?

[Ronda Collier]: No, 2-1 is still pretty okay. You don’t want to be that way 27/7, but a lot of people are. When you start getting really bad is when you are over 4 or 5, which you would be surprised, is pretty darn common and people are even higher.

[Damien Blenkinsopp]: And you were saying it is throughout the day?

[Ronda Collier]: Every time you do a measure you are always – you are sitting at your desk and you can never, ever, get anywhere near 3, no matter what you do.

[Damien Blenkinsopp]: Even if you do some relaxation techniques, some people can’t get it down?

[Ronda Collier]: They can’t get it down.

[Damien Blenkinsopp]: That would actually probably be me, because mine won’t. I know there are some specific reasons, it is not because I am a really stressed out individual. But yeah, that would be me. And I was worried about it a bit more at first until I learned a bit more and I spoke to you at Quantified Self about it.

What is yours, for example? You were talking about when you get stressed at your computer. What does that tend to go up to? What would it normally be if you -?

[Ronda Collier]: I will qualify that with I have been meditating for a very long time. And I did a lot of coherence training with Heartmath for years, and so I will qualify that. But I am pretty balanced. Mine will go up to maybe 2 or 3, which is if I am really stressed. Otherwise I am usually anywhere between 0.8 to 1.5.

[Damien Blenkinsopp]: That sounds ideal, I guess? Is that?

[Ronda Collier]: Yeah, I am pretty balanced. I have worked hard to make my life that way, by the way. It was not always the case. I used to do chip design, which is very high pressure at Silicon Valley startup companies. I wish I had this app then because it would be interesting to see what I was running on, probably full time.

[Damien Blenkinsopp]: I was just going to ask you – that would be so interesting to know how that sort of evolved over time. And especially – this is when I started more meditation, this is when I did this, and you could see the steps down. Because I recently started – I didn’t really know how to track my meditation and if it was effective in any way. And I have been looking for a way to track it for a while.

So these days I go to the part and I switch on Heartmath. I have been using Heartmath to just track my meditation and it seems to be getting better, but honestly I don’t understand the difference between that and say the HRV for stress reading. Could you give me – like, could I use both of these for meditation and try and track how effective my meditation is? Or do you think that is not a reasonable use of it?

[Ronda Collier]: It is. This is a great question and we get this all the time in our support questions. Heartmath is a coherence training device or app, and what that does is get you into a state, basically getting your nervous system and all of your nervous system operating a – it’s called coherent, but in the frequency domain all you have is a little bit of energy at your breathing rate of 0.1 hertz.

[Damien Blenkinsopp]: You told me once before that this was in the LF zone?

[Ronda Collier]: And that falls into the LF. We don’t define what makes HF and what makes LF. So LF is 0.04 to 0.15 hertz, and HF is 0.15 hertz to 0.4 hertz, and that is an industry standard because we follow the HRV standards, and that is what it is.

So if you do coherence training you are going to have a huge spike if you are coherent at 0.1 hertz. And you won’t have anything anywhere else, because that is what coherent is. There is not going to be any energy in the HF range at all, or anywhere else, even in the VLF range, which are the very low frequencies.

So really it is a spike there at 0.1 hertz. And so that will show up as high stress in our app; however, if you are meditating and not doing regular breathing, your breathing normally and then you should be able to see your nervous system actually have a power increase. So that could be a measure of your meditative quality.

[Damien Blenkinsopp]: Do you mean the HF, the parasympathetic, would increase?

[Ronda Collier]: Actually, you could see the whole thing increase. It will stay balanced but the whole thing can increase.

[Damien Blenkinsopp]: I will go and try this for a few days. I go and meditate and I switch it on to the stress and then there is a chart in your app which looks at the LF and the HF and it shows it charting over time. Is that the screen you would look at?

[Ronda Collier]: That’s right, and Sweetbeat Life actually does it in real time now.

[Damien Blenkinsopp]: Okay, what is the difference?

[Ronda Collier]: It doesn’t show LF and HF graph in real time. Sweetbeat shows it in numbers in real time, but Sweetbeat Life, if you go to the landscape mode on the monitor screen, it shows it in real time. So it is a little more intuitive if you are meditating to look at a graph than read numbers.

Be aware though, if you have been doing Heartmath you just go coherent. When I meditate, I just automatically go coherent now so I don’t use it for that anymore. But I do use it in [inaudible 00:25:07].

[Damien Blenkinsopp]: Did you say you don’t go coherent in meditation anymore?

[Ronda Collier]: I do go coherent. All I have to do is think about meditating and I am coherent.

[Damien Blenkinsopp]: Oh, okay. And if you look at the research I am not actually sure that meditation correlates with coherence all the time. And actually if you look on the forums in various places, you will see some people who have been meditating for a while and they try to use Heartmath or something else and when they are in their usual meditation zone, they get a lack of coherence. THey go out of coherence and then when they focus on getting coherent, they go in under coherent. So I don’t know if there needs to be more research done around that. Do you know anything about that?

[Ronda Collier]: Once your nervous system is trained for coherence, and this is my experience, and our other founder Donna Lever, also as soon as she sits down to meditate, she is not trying to go coherent and she doesn’t have a device, but we go coherent. If you want to, you have to be mindful about not doing that regular breathing that brings you coherence. So there are a lot of meditative techniques where you breath in and hold at the top and focus and then that goes – so you just would do a different breathing technique.

[Damien Blenkinsopp]: Right, and breathing does seem to be essential. I think it makes quite a big difference in the Heartmath side. In your app – let’s move back to Sweetwater – does breathing make a big difference to stress numbers, the LF and the HF, in your app?

[Ronda Collier]: Absolutely. While we are not a coherence training device, if you go coherent you are going to see it. And so it will look like – you will see it once again as a spike at LF and so it will show up as stress.

[Damien Blenkinsopp]: Yeah, which in your app would be red, I am guessing?

[Ronda Collier]: That’s right, the stress levels are blue, green, yellow, orange, and red; however, you would be able to look at your power numbers and see what you are doing. You would want to see a super high power number in the LF.

[Damien Blenkinsopp]: Right, and so in your case when you were doing meditation, specifically, you would look at the LF and the HF screen, rather than the bar with the ratings? But just for general stress like you are talking about, you want to understand a situation like if you are stressed or not and if you are feeling a bit rough or looking at your screen and not feeling good or for presentation or whatever – would you use the LH-HF screen or would you use the bar with the red and the yellow and so on?

[Ronda Collier]: I think I would use the bar initially – for your listeners, definitely just use the bar and then once you start figuring out what you are looking at then you can actually look at the LF and HF and that can become second nature, once you are done with the bar then we tend to look at the geek screen at the LF and HF.

[Damien Blenkinsopp]: Right, and then as you said higher power is good as well as the ratio?

[Ronda Collier]: That’s right. When you are really feeling kind of dragging, if you look at the power numbers you could be – I am going to make numbers up. I have had listeners quote my numbers and there is so much variety in HRV numbers, so I am just going to use some average numbers. Some days your LF and your HF might be around 100 or less.

[Damien Blenkinsopp]: Both of them?

[Ronda Collier]: Yes, somewhere around there.

[Damien Blenkinsopp]: So is that a bad day?

[Ronda Collier]: For me that is a bad day. That is a low day where my energy is zapped or I have done something where I am emotionally or physically drained. Then there are other days where you are just on top of the world and you are at 2,000 to 3,000. So that is where you won’t see that from looking at the bar from blue to red, but you will see that looking at your numbers.

[Damien Blenkinsopp]: My numbers would be like – most of the time my LF is like 1,800 and my HF is like 200 or 300, if I am lucky. So if my HF isn’t high enough –

[Ronda Collier]: That’s right. And Heartmath should, over time, improve that.

[Damien Blenkinsopp]: It definitely helps and you can feel it. I guess you recommend to do this kind of thing, but once you identify something that is stressing you in your life and you do a Heartmath session or a meditative session and use the device, then you definitely come back afterwards and you have got more energy, you can get back to what you are doing, and it definitely makes a huge difference in my productivity. Once I discovered this it was pretty much a game changer for how I work.

[Ronda Collier]: Yeah, and you bring up a great point. One of the reasons that we created Sweetbeat was to not only provide you with feedback that you would go off and meditate or chill, but to provide you with real-time feedback so you can actually, right then and there, go, ‘Oh, I am doing this and I have been doing it all the time and I didn’t even know it.’ And then learn to actually correct your behavior right then and there. Put your shoulders back, uncross your legs, sit back, take a deep breath at your desk, and then reset.

[Damien Blenkinsopp]: Right, and so the idea is that you can be watching the screen and you can watch when your numbers readjust or go back to normal and then you can tell when you are in a better state.

[Ronda Collier]: That’s right, and then next time Sweetbeat gives you an alert if you change your stress state and you can program it to do that. So that is how I learned about the screen thing. Other customers have used it while they are driving and it starts beep, and they realize that they have just stressed out over something that they deal with every day. And so it brings to consciousness things that have been previously unconscious that are contributing to heart disease and hypertension in middle age.

[Damien Blenkinsopp]: Would you say this is the most common use case? I was going to ask what you find people are using the most. I guess you have this big database now with everyone’s data. I am not even sure if you have come to grips with that because you have all this data.

[Ronda Collier]: We have not come to grips with it yet. It is going to be a huge issue. What we do is when customers write in and want to know about their data we can help them with an analysis if we have time. We go ahead and look at some of their sessions and give them sort of a bird’s eye view of what is going on for them and so we are still doing that.

[Damien Blenkinsopp]: Yeah, but you can’t do things like understand what, on average, the users are using that for?

[Ronda Collier]: Oh we do, and we have done that. We have a large percentage – the micro market is lead athletes and even fitness enthusiasts using it to guide their training.

[Damien Blenkinsopp]: Right, so that is every morning as soon as they wake up?

[Ronda Collier]: That is that group. That group is also using it throughout the day, running 20, 30-minute sessions just to see how they are doing. Then there is the other market segment, which are quantified selfers and they are wanting to run it for like 8 hours.

[Damien Blenkinsopp]: Right, to see where they spike?

[Ronda Collier]: Absolutely. They want to run a session all day and then they want to sleep in it. They are just running it constantly.

[Damien Blenkinsopp]: When I first got mine I wanted to do it 24 hours and I think I even wrote to you about it.

[Ronda Collier]: Yeah, your phone won’t hold all that – there is a lot of data.

[Damien Blenkinsopp]: That’s what you told me.

[Ronda Collier]: But with the health patch we are working on making that a little easier for folks. So the health patch will make the full time monitoring much more accessible because it is actually comfortable and you don’t even know it is there. You can sleep in it without the strap on you, though some people don’t mind. I don’t sleep well with the strap, but the little health patch just sits there and it is not a big deal.

[Damien Blenkinsopp]: Anyway, the idea behind the 8-hour or the 24-hour is people are trying to figure out, and using the stress monitor, what kinds of things are triggering them throughout the day. This is what they are doing, right? They are just mapping the whole day and they are like, ‘Hmm, at 1 o’clock and 3 o’clock I got really stressed out, what was I doing?’ and that kind of thing?

[Ronda Collier]: Yeah, that’s right. And also they are tracking LF and HF. A lot of the folks have gotten big into looking at those numbers because once again, the stress meter only tells you the balance of LF and HF. The numbers themselves tell you the power levels.

[Damien Blenkinsopp]: So it is more interesting once you start looking at LF and HF?

[Ronda Collier]: People love the power levels, so yeah, it is really great and we were really pleased with that.

[Damien Blenkinsopp]: Yeah, is there a more detailed understanding though? As you have already described? A lot of people probably want to get their HF up higher and I guess there are two ways to look at it as the baseline, where you are from day-to-day. And I don’t know if you do kind of averages of how people evolve over time and they manage to address that kind of baseline versus –

[Ronda Collier]: You are bringing up a really important point for your listeners. Because HRV has a circadian rhythm, if you are going to do a day-to-day comparison you need to do it at approximately at the same time in the same position. If you are laying down and then stand up your heart rate increases to equalize the blood pressure. So really your position is important.

Also, your mental state will be important. So if you measure it at the same time each day but one day you are all stressed because something happened in your family, your HRV is going to be different. That is why we recommend that people do it first thing in the morning and really mindfully don’t start thinking about your day because that can affect the reading.

[Damien Blenkinsopp]: Yeah, what I do every morning now is I lie down and then I do a standing up reading as well. Which do you do? Do you both or do you just do lying down or standing up?

[Ronda Collier]: Well I just do lying down. I am lying in bed and I am not thinking, because once I get up then my mind starts thinking about my day and so that can affect the readings. We have done measurements where something was going on in my family and I was just sitting here and already had the strap on when I was testing in the early days and something happened and just from my thought and looking at what happened my stress soared right in front of my eyes and it was kind of crazy.

Our other founder, Joe Beth Dow, had the same thing happen. So really your mental and emotional state, if you are going to do the day-to-day comparison, you need to be mindful of that. And if you see it drop just really go inside and go, ‘What am I feeling sick? Or sad, or angry, or upset, or something like that.’

[Damien Blenkinsopp]: Right, to kind of detect if it is something you are causing yourself or if it is the underlying how you are feeling today, that is a good point.

[Ronda Collier]: That’s right. It can be physical, emotional, psychological, or environmental.

[Damien Blenkinsopp]: Yeah, I can definitely relate to what you are saying about it is easier when you are lying down when you first get up and then you tend not to think about it so much. But I do the lying down one and then I do the standing up one and I tend to start thinking about things. And I have to kind of catch myself, especially if I am thinking about work or something. So I think you are totally right about that, if you are going to do the standing one it is good to keep in mind that it is at the same time.

The other thing is movement. HRV for training is a very specific, three-minute reading. So you either do it lying down or standing up or sitting down.

[Ronda Collier]: Do your three-minute reading and you are done, yeah.

[Damien Blenkinsopp]: And you always do it the same just to keep it the same. How about movement? I guess some people doing these 8-hour cycles are also tracking all sorts of things throughout the day. Is it relevant to track HRV while you are moving? Is that an accurate reading? I had some experience with this before and I couldn’t really figure it out. What is your take on that?

[Ronda Collier]: That is another great question. You should see your heart rate variability changing through the day. When you go from sitting to standing or lying down to standing your heart rate should increase and your sympathetic should increase to increase that heart rate. So you should see nice cycles throughout the day. If you are not then that is a serious problem and that would be indicative of someone with some heart disease.

[Damien Blenkinsopp]: You are saying if the power levels aren’t changing, as you are doing different things?

[Ronda Collier]: That’s right, or even the stress level, which is the balance because I will repeat the example and when you are lying down and standing up – when you go supine to standing your sympathetic nervous system kicks in to increase your heart rate, to pump your blood, or to equalize the blood pressure. And that is normal.

For people who have low HRV to a point that maybe it is a heart disease, they have a hard time and their heart can’t respond and their nervous system is brittle, if you will. And so when they go from lying down to standing up their heart rate doesn’t increase the way it should.

And so if you were to go throughout your day in 8 hours and not see a lot of variety in your power levels and your stress levels, that would be a problem.

[Damien Blenkinsopp]: The HRV readings are accurate in terms of the LF and the HF – it is accurate data when you are moving around it is just that it is changing a lot. So your HRV should go down, I guess? In this case it is going to be the stress. So would you be more stressed when you are moving around, if I am walking or running it is going to be more sympathetic? Or can it vary per person?

[Ronda Collier]: It really depends. We were wearing it at CES the last year, or the last two years, and these kind of things usually stress me out. I guess I decided that I am not going to let trade shows stress me out anymore. I did, actually, mindfully because I will just go bonkers. And I needed to be present to go talk to all the people were were going to meet with.

And so I was walking around CES with a completely balanced green to yellow stress, which is pretty good. And really the numbers were high and I was just in a good space. Now, if you are running and exercising then your HRV is going to drop and that is just the nature of the beast.

But it is really more about that you are going to see the variation when you stand up and sit down and sit down and stand up or have an emotional stressor, or anger or environmental something coming at you.

[Damien Blenkinsopp]: Yeah, so it is not that there aren’t any people using this to track their exercise – are they tracking their HRV or their stress?

[Ronda Collier]: Oh, these guys use it for everything.

[Damien Blenkinsopp]: Is there any research behind that? What kind of understanding could you get?

[Ronda Collier]: Sweetbeat was not designed to be used while you exercise. There are some things you can glean from that. In fact, you can see where you hit aerobic to anaerobic if you know what you are looking at.

[Damien Blenkinsopp]: That is interesting.

[Ronda Collier]: It is, it is very interesting. We just having pursued that, but I can see it.

[Damien Blenkinsopp]: Can you give us a quick add to that or is it more complicated?

[Ronda Collier]: Yeah, it is okay – so your stress level goes up and your whole power levels just plummet. Your HRV plummets because everything is moving so quickly. And when you hit that threshold your stress level on the colored bar actually goes down when you hit that threshold, so that is the easiest way because your HF actually kicks in.

[Damien Blenkinsopp]: Your HF you are saying will go up when anerobic starts?

[Ronda Collier]: Yeah, and remember you are down in numbers in the teens now. So your listeners that want to try it, yeah.

[Damien Blenkinsopp]: Yeah, they should try that out.

[Ronda Collier]: Look at the geek screen and watch the numbers. Pay attention and then you will be in the red and then suddenly when you go a little harder it will back down and the bars will be like in the yellow and in the green.

[Damien Blenkinsopp]: Wow, that is really interesting. That would be interesting if you guys do something with that later.

[Ronda Collier]: And there is a bunch of research on that too. It is so dynamic and it is kind of hard to do in an app, but we think about it.

[Damien Blenkinsopp]: So I guess you will have some complicated algorithms you will have to develop and it might take some more research. It would be interesting if you could do that because currently the tests – I looked at different breath tests and so on you can do to establish anaerobic threshold. And it is not easy, you have to go to the labs and mess around. So eventually if we had an app like your iPhone app that would be really cool.

[Ronda Collier]: Yeah, I have done one and they pushed me too hard – I need to warm up. I do. And so they got completely wrong measures, said my max heart rate was like 150, which is just not true. I go to the gym and hit 165 all the time but I need to ramp up. So going on a full-force run in the first minute just doesn’t work for my body.

It would be cool to have an app that would let people – there needs to be a protocol because we have done enough looking into it with that, but not in the first minute, come on.

[Damien Blenkinsopp]: You have probably got your hands full with all the other stuff going on in your app already, so it is probably not for tomorrow. I just want to go back and we have touched on circadian rhythm a few times, saying how it distorts the figures. So I want to make sure the audience doesn’t get confused with that point. Is there a specific pattern? If I am looking at stress over the day, is there any way I can picture it in my mind so it will be a bit higher at this point or a bit lower at this point?

How do you look at the circadian rhythm? I guess the first thing to say is if you are doing HRV for training it should be at the same time every day? I woke up at one time at 4 o’clock in the morning, which I sometimes do, and then other times I will wake up at 8 o’clock and do my reading then. And one day I did it at 4 o’clock and it was completely different. It was actually a lot worse and I don’t know if that fits the typical theory. But I was like, ‘I think I better take this a bit later.’

[Ronda Collier]: It’s going to be individual, but typically – and I am just going to give you a typical case. Your HRV will be highest in the 6 am, 7 am, 8 am. And then it dips down in the early afternoon and then it comes back up in the evening.

[Damien Blenkinsopp]: And then it stays up during the night?

[Ronda Collier]: While you are sleeping your HF really should kick in and that is why people measure it when they are sleeping. If your HF isn’t kicking in then you are maybe not getting very good sleep.

[Damien Blenkinsopp]: That’s me, but we won’t get into that. That is why at 4 o’clock it was terrible. So you basically gave us the outline there. So in terms of stress that would be reflected in the stress levels as well, so you are saying in the afternoon you probably have the worst stress levels? It would be harder to be non-stressed in the afternoon, is that what you are saying?

[Ronda Collier]: Actually, I can give you mean. All I have is research numbers, so the only thing I can tell you from personally looking at the HF and LF numbers are that my HF kicks in the afternoon, which causes my heart rate to decrease, and I am sleepy.

[Damien Blenkinsopp]: Is that because you have trained yourself to have a nap?

[Ronda Collier]: But everything is low, so my HF will go from maybe 3,000 in the morning down to 900. But I am still HF-dominant, so once again, that goes back to the power numbers. They are just really – once people use Sweetbeat and get used to the stress levels then really dive into the power numbers because that is saying so much about what is going on for you.

[Damien Blenkinsopp]: And so your aim there is – 3,000 sounds incredible, like for my levels. You are saying that over time you would really like to get the HF up, that is the idea? To increase the power of the HF?

[Ronda Collier]: Yeah, most people want their HF up because they are sympathetic-dominant and kind of chronically stressed. So we have done a few case studies with yoga, so actually a young woman was one of the case studies in her early 20s who just felt stressed out, always. So her HRV was always on the low side and she was sympathetic-dominant. So she did yoga twice a week for six months and brought that into balance. She raised her power levels and brought herself much closer to balance.

[Damien Blenkinsopp]: How was she tracking that? Or how would you advise if someone is doing a long term intervention like that where they are doing classes twice a week or they are doing meditation once every day, how would you advise them to best use the app to track that?

[Ronda Collier]: I would do the HRV for training but if you are looking at LF and HF, I should mention this, it is better to have a five-minute reading or longer because with our algorithm, once again we use the industry standards for heart rate variability and there is what is called a short-term measure, which is five minutes, and a long-term measure, which is 24 hours.

So our algorithm is designed for a minimum 5-minute window. So you would not want to really use HRV for training because that is designed for the time domain accuracy and it is not the best. You are not going to get the most accurate LF and HF in the three minute, but you want a five minute.

[Damien Blenkinsopp]: Great, so your HRV for training switches on and off and it does the three minute and then it is finished. It is all built in so you don’t have to worry about that and it is going to do it for you?

[Ronda Collier]: Yeah, that’s right.

[Damien Blenkinsopp]: But what you are saying is that for the stress monitor it is labeled stress monitor in your app, as I remember, and that one you have to do for five minutes?

[Ronda Collier]: Yeah, at least. And usually you just want to put it on either right when you get up in the morning and do that, or still when you are kind of relaxed somewhere, maybe watching TV in the evening, or pick a time when you are kind of unwinding. So if you are doing the six-month intervention, pick a time a couple of times a week or every day that you go ahead and measure yourself and the history and the charting and you can see what your trends are.

[Damien Blenkinsopp]: So ideally that is the same time every day and should be the same activity, like you are saying – if it is always watching TV, although I think if you are watching an action film versus a romantic film or something it might have a little bit of an impact there too, so you have to watch out for that. Great.

[Ronda Collier]: That’s right, and if you have a favorite program that you always watch you should measure during that.

[Damien Blenkinsopp]: So you mentioned yoga – are there interventions that you know people have done in your user base? Are there examples of good things to try out in terms of experiments? What would be the top five things to try to raise the baseline?

[Ronda Collier]: Definitely yoga and meditation, those kind of go together. Nutrition, of all things, stop eating anything that is out of a box. Read the labels and if there an ingredient you can’t pronounce, don’t eat it.

[Damien Blenkinsopp]: So that would be easy if you start a diet on the first of the month. And then you can, over time, probably see some change over the next weeks if it is a positive change or a negative change?

[Ronda Collier]: That’s right, because our bodies are completely interdependent and interconnected. All the systems are connected to the other. Sweetbeat also has, which I haven’t mentioned, a food sensitivity test. And it allows you to test for foods that you may not be allergic to but you are sensitive to. And these foods can actually cause your heart rate to increase by quite a bit, even if you are just sitting.

So we have case study after case study of people sitting quietly at their desk, watching TV, or relaxing, and their heart rate goes up 20 beats after eating the offending food.

[Damien Blenkinsopp]: Did you base that on research? Where did that come from?

[Ronda Collier]: It’s called Dr. Coca’s Pulse Test – I think it is Coca’s Pulse Test. And Dr. Arthur Coca was a renowned immunologist in the 50s, founder of the journal of immunology, so he was quite well-known at the time. And he came up with this simple test to help his wife, who was having issues where they couldn’t find it in allergy tests, but they were suspecting that she was allergic. And so he came up with this pulse test for her and so she was able to fix a whole lot of ailments by using the pulse tests and eliminating offending foods.

And so all of the inflammation and all of that interacts with cortisol. There is stress cortisol and that is why I mentioned nutrition, because it is all interrelated and so if you are eating things that you could even be slightly sensitive to it can affect your heart rate variability.

[Damien Blenkinsopp]: Is it in peer-reviewed journals, this kind of research, as well? Or is it Dr. Coca’s? It sounds like it makes logical sense. Has anyone done any studies on it to validate it?

[Ronda Collier]: I could not find any peer-reviewed journals on this; however, they do teach it in medical school so a lot of allergists know about it. So yeah, it is very interesting that I have been unable to find any because we at Sweetwater go to the National Institute of Health database for our research. We want peer-reviewed research that will back up our algorithms. So yeah, the Coca pulse test, no, but a lot of functional medicine doctors, MD or not, use the pulse test and are familiar with it.

[Damien Blenkinsopp]: So it is worth finding out to see if there is something?

[Ronda Collier]: Absolutely.

[Damien Blenkinsopp]: Is there anything you would advice – and maybe you don’t know about this – but say if something is showing up and it looks like an analogy, what would be the next step for someone to try to get more validation around that? Have you got any suggestions, or is that something kind of out of your area?

[Ronda Collier]: Take it out of your diet. If you eat something, what the app does is if you are wearing a heart rate monitor it automatically will take your pulse at 30, 60, and 90 minutes. And assuming you are not out running or exercising, if your heart rate increases then that is not good.

So what you would do is note that and basically remove the offending food.

[Damien Blenkinsopp]: Yeah, so a lot of functional doctors these days advise – because a lot of the allergy tests aren’t that consistent either, so a lot of them advise you on elimination anyway. So I guess if you really wanted to validate it afterwards, don’t eat it for a month. And then eat it again and see what happens to you or if you feel worse, and again do the test with your app, for example. That is probably the next best thing to do?

[Ronda Collier]: That’s right. I wasn’t testing anything but I ate – and a reasonable, regular serving of cherries about a month ago. And I was just sitting at my desk and I was testing the Sweetbeat for something else and I wasn’t doing a food test, but I noticed my heart rate was 79. My resting heart rate is about 50 and I was like, ‘What is this all about?’

So I looked it up and a lot of people are sensitive to cherries. And I could feel my heart pounding. And so I am really aware, and I am going to retest cherries.

[Damien Blenkinsopp]: You are probably becoming a lot more aware about yourself and notice a lot more things because what I have found when you are using these kinds of apps it kind of validates tiny little – like if you feel a little bit off, it starts to validates you and you start to get more confidence in trusting yourself and starting to notice more because of that. So it is probably not something you are telling everyone, but using these HRV apps for this kind of apps for this kind of thing can help build your awareness of yourself over time as well.

[Ronda Collier]: That reminds me, sort of back to what people have done to improve their HRV. [inaudible 00:49:14] cofounder, walking in the park, in green – she learned a few things because her HRV was on the low side when we started Sweetwater and now even through a whole bunch of life events, a mother passing away and so her HRV has continued to increase through the years because she learned the things that increase it so she does them every day, versus doing them haphazardly.

[Damien Blenkinsopp]: Let’s get back onto the – what other kinds of things have we missed? We talked about yoga and meditation.

[Ronda Collier]: That is another one, we have done some research on – another one is acupuncture so we have done lots of case studies and actually there is peer-reviewed research on acupuncture. We have done some ourselves and your nervous system just balances and power levels increase during and after an acupuncture session, so that was another interesting one.

[Damien Blenkinsopp]: That is quite a controversial area. I know there is a lot of functional doctors who really support it and there is also a fair amount of research there. But when you bring up acupuncture a lot of people find it controversial still.

[Ronda Collier]: Well that is changing, and insurance reimburses acupuncture for people with arthritis. So Western medicine does acknowledge and that is why there are a lot of peer-reviewed papers surrounding acupuncture. They know and they can measure that the pain receptors have changed, specifically around the points for arthritis treatment.

[Damien Blenkinsopp]: Well here is the thing – I think acupuncture is a bit of an art, so some people might be better at it than others? Is that the way that it works? Could you evaluate the quality of the acupuncture you are getting based on the impact on HRV?

[Ronda Collier]: Yeah, absolutely. I have a good acupuncturist so I have seen my nervous system change about 20 to 30 minutes after the needles go in, which is about what you should expect. Another is chiropractic – we hold our stress in our bodies and there are, once again, peer-reviewed papers on chiropractic and HRV.

You can see whether the adjustment made a difference to you or not, so it is sort of an objective measure in general to some of these treatment venues that some people are not sure of, like acupuncture and chiropractic. You can actually measure whether it made a difference.

[Damien Blenkinsopp]: Yeah, so it is useful, especially if you are doing something new that you are not sure about, whether it is yoga or whatever you are trying that is new. I guess it also help your motivation, so if you can see the numbers changing it is this low thing, but if you can see that positive feedback you are like, ‘Oh, this is making a difference.’ Whereas sometimes – that can give you more motivation just to keep at it because you can see things changing.

So I know we have gone on quite a long time here and I wanted to make sure we cover a couple of other things, which is your new app and the correlation in particular, which has been added. Is there anything else new that has been added or is that the main thing?

[Ronda Collier]: Better graphing features and like I said, some of the real-time graphs. The Vital Connect patch so you can see real-time calories burned, once again accurate. I have a Fitbit so don’t get me wrong, but it is not accurate. Neither are the machines at the gym, by the way, but this gives a real accurate calorie burn.

It also gives – let’s see, respiration, body temperature, and calorie burn. It does measure number of steps and all that, as well as all of our HRV values.

What is new in Sweetbeat Life besides the Vital Connect patch, which has all that new information for you in real time – we have a correlation feature that allows you to basically correlate your HRV and stress levels to all the other parameters in the Vital Connect patch as well as correlate to your Fitbit, the number of steps you are taking, your calories burned, your calories eaten, and we also connect to Withings, so we have the withings scale and so your weight is in there as well as the Withings blood pressure.

One can learn what am I doing when my HRV is good? How many steps, how many calories? Or what am I doing when my weight is where I want or not want? I personally learned that it is not calories in versus calories out for me that helped me get to my desired weight – and we are talking three pounds here and it is important. It is the calorie out. I need to eat more and burn more and then I actually can lose weight easier. So that was important for me.

[Damien Blenkinsopp]: Right, so you are saying you saw a correlation with intake and activity levels?

[Ronda Collier]: That’s right, burning 1500 and eating 1200 I didn’t lose weight. But eating 1700 and eating 1400, I did. And so that was really important for me. And a lot of people will be concerned about what they are doing to maintain the proper blood pressure or stress levels and so on, so it is really a great tool to bring meaning to all this data.

[Damien Blenkinsopp]: And when did you launch this? I think it is the early stages in the understanding of the use cases.

[Ronda Collier]: Yeah, we launched in May. And if anyone does decide to try out Sweetbeat life, we have great videos embedded in all the screens now. For the correlation function we have put a lot of information on a very simple screen, so it is very important to watch the video and pay attention. Because once you know what you are looking at then you hit the buttons and there are all these buttons to see all this great information and you know what you are looking at.

But when you first go looking at it, you are not going to understand it, so please do take the time to look at the video. That is just the nature of trying to convey a lot of information on a small screen.

[Damien Blenkinsopp]: Yeah, and so what are your plans for that? Right now the correlations are between data of the Fitbit data and the Withings scale. What are the main areas people are correlating?

[Ronda Collier]: And the map my fitness, to measure how many mets your workouts are as well – just adding more, first we are going to stay where we are right now and get customer feedback on this. Once again, it is a lot of information crammed into one tiny screen, so we want to get that right first and find out what is useful to the customers and then do an iteration there and then just start adding more of the popular tracking devices.

[Damien Blenkinsopp]: Yeah and it sounds like you are going to learn as you go because you don’t know what is going to correlate either. And eventually patterns are going to pop out so it is going to be more interesting to integrate with some devices versus others.

[Ronda Collier]: That’s right, and one of our favorite scenarios is with the athletes that have been training using Sweetbeat and measuring all these things with let’s say blood pressure, weight, you name it, for a year and then they have Iron Man coming up. What we want to do is provide them with meaningful information of what they were doing that consistently got them into the most rested and ready state.

[Damien Blenkinsopp]: Yeah, like you were saying if they have six months of data or whatever that would be pretty amazing.

[Ronda Collier]: Yeah, and then they can go back and create this is what I was doing that consistently gets me to where I want to be the morning of the race, and so this is what I am going to do.

[Damien Blenkinsopp]: Whose idea is this? I don’t think anyone else is doing this yet. Obviously this is where people have been talking that things should go in terms of correlation.

[Ronda Collier]: This was our idea and oddly enough this came from an app challenge that we were going to do with Qualcomm Life. And Qualcomm Life collects data from so many different devices and so we were just going how can we show the value of the Qualcomm Life platform? And so that is what really led us to do this at the timing that we did it. So we are very grateful to Qualcomm LIfe for having that app challenge when they did because it really pushed us to get this together. So we really are the first people creating useful information besides just a dashboard with charts for all this data that everyone is collecting.

[Damien Blenkinsopp]: Yeah, and it will be interesting to see what kind of experiments they try to run and what correlations they can come up with. So how many users do you have using the Sweetbeat versus the new one? It has been out since May?

[Ronda Collier]: The new one has only been out since May so we have under 1,000 on Sweetbeat Life and tens of thousands on Sweetbeat.

[Damien Blenkinsopp]: I know you have got all this data – have you got any plans to try and sort through any of that? What are the most exciting things coming up next that you have ideas about? Or do you have ideas that you hope to do in the next two years?

[Ronda Collier]: I would have to kill you if I told you.

[Damien Blenkinsopp]: I thought it might be something like that.

[Ronda Collier]: We have a lot – that’s all of our secret road map. But we are doing some really cool stuff coming up and we are so excited, that is all I can say. And the health patch has really enabled this because it opens up a whole new market of people that frankly are not going to wear a chest app. They are just not going to put it on, so the patch really makes it more accessible. That allows us to create products for an audience beyond the Quantified Self hacker that will stick to the strap on or the athletes that already have straps.

[Damien Blenkinsopp]: How much does the patch cost?

[Ronda Collier]: So the starter kit is $199 and that comes with five patches and the electronic module.

[Damien Blenkinsopp]: So it is like $40 a patch, and they last – you said you used yours for -?

[Ronda Collier]: Well the replacement patches are $20, so a month or more depending on what you are doing with it .The price point is high because it is a brand new product, but that is going to be coming down as the volume ramps up, obviously.

[Damien Blenkinsopp]: It is brand new and I saw it.

[Ronda Collier]: It is brand spanking new. The only place you can get the health patch right now is through Sweetbeat, and we are the first app out with it. Consumers can expect that number to coming down in the years to come, like I said, as the volumes ramp.

[Damien Blenkinsopp]: Great, thank you very much. Just a couple of questions more about you and the way you use data in your life. What would be your number one recommendation to someone trying to use some form of data to make better decisions about their body’s health performance? What would be your number one recommendation?

[Ronda Collier]: Actually I think our correlation feature is our number one recommendation for me because it is giving you really useful information. HRV, for your listeners, should be measured along with your blood pressure, your weight, and your cholesterol because HRV perturbations are early indications to something that hasn’t shown up physically yet.

So if you are monitoring your HRV as you go through your life and you suddenly saw a drop, a consistent drop, then there is a problem. And then with the correlation feature you may be able to go back and see other aspects start to change with the lowering HRV. You can’t take one thing in isolation.

[Damien Blenkinsopp]: So you are using it as a discovery problem that you can’t see, because most health problems in our life take us by surprise.

[Ronda Collier]: Yeah, so I have the Withings scale and the blood pressure cuff and a Fitbit and I use iFitness.

[Damien Blenkinsopp]: So it is like risk management?

[Ronda Collier]: That is right, that is right, and learning what I can do. Sometimes, especially with weight loss, people are like, ‘I don’t know – I count calories and I do this and I do that. Why am I not losing weight?’ Then suddenly they will lose a couple of pounds and this will give some really useful feedback. I also want to mention on that vein that getting accurate calorie burn during the day – if you are really on a serious need and you need to lose 40 or 50 pounds, that is a long haul.

And 200 calories a day is a big deal when you are tracking, so getting an accurate calorie burn throughout the day is important. So really being more accurate, and Sweetwater health is really about more accurate feedback for the consumers and athletes.

[Damien Blenkinsopp]: Yeah, because there are a lot of apps out there and they are definitely not the same. I got the Mybasis watch and I think you know that compares unfavorably to some of the other trackers.

[Ronda Collier]: Yeah, we bought a Basis to check it out. And you have to wear it too tight on your wrist that it is not comfortable if you want heart rate. And it just doesn’t match my outfit.

[Damien Blenkinsopp]: Right, and just talking about the My Basis quickly, the reason you can’t do heart rate variability is that they are just not sampling quickly enough? Have you looked into it?

[Ronda Collier]: Any wrist face device, like [inaudible 01:00:52] use pulse oximetry, so what they are looking at are the capillaries in your skin as they expand and contract, so it is just very difficult to get very accurate beat times.

[Damien Blenkinsopp]: Right, so they are using averages to get the heart rate and they need way more accuracy to get to heart rate variability, which is more difficult than a heart rate. On My Basis if you start running around it starts losing track because your heart rate is moving, so it can’t even keep track of your heart rate.

[Ronda Collier]: Because it is motion and the pulse oximeters are very motion-sensitive because they are basically measuring capillaries and if you move your skin the capillaries are moving. And so Mio, just for those athletes, the Mio Alpha has done a terrific job of eliminating motion artifacts. You can actually use that one while you are running and still get an accurate heart rate.

[Damien Blenkinsopp]: A heart rate, but not heart rate variability.

[Ronda Collier]: No, and they want to do heart rate variability but they are also engineers and so they just know that they can’t.

[Damien Blenkinsopp]: They are struggling but potentially one day that technology might –

[Ronda Collier]: Potentially one day, yeah. If you can get the processing power without draining the battery in a watch it can be done.

[Damien Blenkinsopp]: You have probably told us some of this already. What data metrics do you track for your own body on a routine basis, like the things that you would keep in mind every month or every six months? What are the key five things that you think are most important for yourself?

[Ronda Collier]: I keep track of my HRV and I am aware of my blood pressure. I am also aware of my resting heart rate and I don’t know why, but I want to know. Mine actually drops low sometimes so I am worried on that end, it gets around 40 and I sort of want to keep an eye on that. I weigh myself, and weighing yourself every day is stupid, sorry. I weigh myself probably once every month or two and keep track of that.

You don’t want to – because pounds creep up and suddenly you are ten pounds overweight. And I track my steps because I work at home and you want to make sure you are moving your body. I exercise every day but man, if i don’t go out to the gym or go hike or do something like that –

[Damien Blenkinsopp]: Thank you very much for that. it is always interesting to hear what different people are focused on, especially when you are so involved in tracking yourself, so it is always interesting to hear what you focus on. Ronda, this has been an exceptional interview with tons of detailed information about how your app works and how you can use it. Thank you very much for your time today.

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Whether you’re a professional athlete or a weekend warrior, taking a break from mental work to hit the gym at weekends, recovery is an important part of how you train.

When we don’t recover sufficiently we end up decreasing our performance and health rather than getting the results we desire – higher performance, beating our records and increasing our health and wellbeing overall. In today’s chronically stressed world, it’s all too easy to over train as we are so used to the constant stress burden.

Most people are aware of this now. But it’s still difficult to manage, even with this knowledge. How do we know when we need to take a break from training? When a workout is going to have an overall negative impact rather than the positive one we seek?

Enter “Heart Rate Variability” also known as HRV.

HRV is being increasingly used by professional athletes and the everyday gym goer to attempt to better manage recovery by providing an estimate of when we are over stressed vs. well recovered. Trying to answer the question – should I leave it a few more days before my next workout? Or should I go easy in today’s workout?

Over the last few years a large number of devices and applications have been hitting the market so HRV is a lot more accessible now. With just an iPhone or Android app and a relatively cheap sensor you’re ready to go. While many of these HRV apps look very straightforward, there is actually a lot to them with different metrics, and correct vs. incorrect approaches to using them.

To cover the HRV topic in depth, today’s guest is Andrew Flatt, owner of the blog HRVTraining.com – which is one of the best resources on using HRV for training I’ve found to date.

Andrew is a PhD student at the university of Alabama who has been working in the Human Performance Lab at Auburn University on research related to HRV and exercise. He has been making use of HRV since 2011 to monitor and optimize his own training and that of the athletes he coaches. He is also an accomplished athlete himself, and was the 2010 Canadian National raw powerlifting champion.

Andrew is very hands on and has done a lot of on the ground work with HRV, so he has a great practical as well as research-based perspective on how to use heart rate variability to optimize training.

itunes quantified body

Show Notes

  • What HRV (Heart Rate Variability) is and what it measures
  • How to use HRV to optimize your workout schedule, cycling of workouts and recovery from illness
  • The mechanisms behind HRV: vagal tone, autonomic nervous system activation, sympathetic and parasympathetic activity
  • A review of the different HRV metrics, and why RMSSD is recommended for convenience and non-professional use
  • The devices and apps you need to track your HRV at home and their accuracy (EKG/ ECG, finger light sensor, ear light sensor, phone and web apps)
  • Additional features that are useful in the apps to give more meaning to the HRV data
  • The impact of lifestyle activities on HRV (partying, sleep, sickness, alcohol and diet)
  • Benchmarks of HRV scores for strength and cardiovascular athletes vs. non-athletes – what’s a good HRV that indicates good recovery? What’s a bad HRV that indicates a need to recover?
  • Taking your readings methodology – arguments for Supine (lying down) vs. standing up
  • How and when to take your HRV readings to ensure that the data is accurate and meaningful for optimizing training
  • How HRV varies according to your age, gender, lifestyle, training schedule and type of training (cardiovascular vs. strength/ resistance training)
  • What Andrew sees coming up over the next years in the HRV domain and how it’s going to be useful
  • Andrew’s top recommendations on using data to improve decisions around training and health

Biomarkers in this Episode

  • Heart Rate Variability (HRV): Measures how your heart rate varies over time. Research studies link HRV to recovery status, stress and other aspects of human physiology.
  • R-R intervals: Time interval in between heart beats (R = peak of heart beat).
  • Resting Heart Rate (RHR): Measure of your heart rate at rest (typically measured upon waking).
  • RMSSD (Root Mean Square of the Successive Differences): A measure used to calculate HRV that has proven to be reliable and is used in a lot of the research studies – Andrew’s preferred measure.
  • lnRMSSDx20 (RMSSD with natural log and multiple of 20 applied): Applications have begun using this measure, which is basically RMSSD scaled to an index of 100, to make it more user friendly.
  • LF (Low Frequency): Spectral measure that indicates combination of parasympathetic and sympathetic activation.
  • HF (High Frequency): Spectral measure that indicates parasympathetic activation.
  • Coefficient of Variation (CV): Measure of variance across a set time period (Andrew has found to have good correlation vs. weekly mean value).
  • 7-Day Trailing Average HRV: Average of HRV values used to track your progress over time. Andrew uses this mostly to guide his training now.

Devices/ Apps from the Episode

Other Resources Mentioned in this Episode

Interview Transcript

Transcript - Click Here to Read
[Damien Blenkinsopp]: Andrew, thank you very much for coming on the show. It is a great pleasure to have you here.

[Andrew Flatt]: The pleasure is mine, Damien. Thanks for having me.

[Damien Blenkinsopp]: Thanks. What I thought we would do to start with is jump into what is HRV a little bit – Heart Rate Variability – so that people who haven’t come across this before can have a rough understanding of what it is and where it was.

[Andrew Flatt]: Sure. So heart rate variability often gets confused with basic heart rate, which is measured in beats per minute. Heart rate variability differs by measuring the actual time difference between heartbeats.

So on an electrocardiogram we R-to-R (R-R) intervals and from breathing patterns there is variance between successive R-R intervals. And what heart rate variability is doing is capturing those changes between those heartbeats.

So it is a little bit more specific of a measurement but it is not dissimilar from basic heart rates, so people shouldn’t get too confused with it.

[Damien Blenkinsopp]: So could you give me a quick overview – what is heart rate variability, HRV, and how do you use it? What is it all about?

[Andrew Flatt]: So your resting heart rate is generally not consistent. We learn in a textbook that a heart beats approximately every 0.8 seconds for an average of 75 beats per minute. What that doesn’t factor in is the actual changes in heart rate, the subtle changes that, in response to respiration, where when you breathe in your heart rate actually speeds in a little bit and when you breathe out your heart rate will slow down. And that is normal.

That is called respiratory sinus arrhythmia. And essentially what heart rate variability is capturing is those subtle changes in heart rate in response to respiration. So heart rate in beats per minute is kind of giving you that average of how many beats there were, whereas the variability is telling you how much variation there was between the beats.

Now, there are various statistical procedures and so forth that we can assess variability. There is a standard deviation, there is the Rubian square, there are spectral analyses. So there are various parameters for heart rate variability but in a nutshell it is just measuring the variance and changes between the time interval between heartbeats.

[Damien Blenkinsopp]: Right, and you brought up a little bit of terminology there – it is R-R intervals, which is basically R means the top of the beat, the kind of spike of the beat that you kind of see on the electrocardiogram, so R-R just means the time in between beats, correct?

[Andrew Flatt]: Right, because they are such high peaks it is really easy to measure the interval between them so that is generally why the R-R intervals have been used.

[Damien Blenkinsopp]: Right, and just out of interest, why is it called an R? Why isn’t it called a beat?

[Andrew Flatt]: The peaks are just alphabetically named. There is the P, QRS complex, the T-wave, so – we just –

[Damien Blenkinsopp]: And the peak just happens to be the R, good. So I know that you have been using HRV in a bunch of areas to basically make better decisions, mostly about training. Could you talk about the different scenarios you have been looking at it with and where you find it most useful?

[Andrew Flatt]: Well, I think it just comes down to why I started measuring heart rate variability. I first learned about it just reading on some strength and condition forums, a website called [lead ips .com 00:03:22]. And there were some strength coaches talking about how they are using it with their athletes, so I kind of gained interest in it then.

But it wasn’t until I was preparing for a powerlifting competition and training was going really well. I was pushing it real hard and I was set to set some personal record at a lighter body weight when all of a sudden, I took a dive and I actually got a little bit of a cold. I took a few days off from it and I went back and hit the weights and things were just feeling real heavy.

And it was too close to competition for me to really fix things and I actually ended up pulling out of the meet and I was really disappointed. And I thought to myself there has got to be some kind of way that I can better manage my training and maybe kind of prevent this or see it coming a little bit better.

So that was kind of the motivation to actually purchase a heart rate variability device and start using it. So my original motivation was to guide my own training. I am involved in powerlifting so it was kind of a selfish motivation more so than working with athletes, but eventually that is kind of where it came to, where I would actually start using it with athletes.

I was training friends and colleagues and I would get them using it and look at their data. And that is kind of how things went from there.

[Damien Blenkinsopp]: So you obviously found it very useful, to have gone into an insight using this with other people now. So what kind of decisions do you make based on this? Is this is the only indicator you use? Is it the main indicator you use with your training program and deciding when to change up the variables?

[Andrew Flatt]: You know, when I first started using the device I was very skeptical at first. I didn’t know much about it other than what I read on the forms and what I actually did was for six months I used it and collected data, but I did not use it for any kind of decision making.

In fact, I really didn’t look at the trends or analyze anything until after about six months when I would kind of look at the trend and I would look at my training log and I would try to see what it was telling me in the first place. I think one of the biggest mistakes is people get a device and they think they know how to use it and then they want to start making decisions with it.

I think you almost want to do some kind of cross validation with it on yourself first and see what it is telling you in response to training or in response to different kind of life events – you get sick, you travel – what is it showing you? Is it meaningful? Can that drive better decision making?

And essentially, what I found was after six months of using it I would look back on it and after heavy training sessions I would see a decrease in my HRV score. Most noticeably I would see, after any kind of a new training stimulus, so being involved in powerlifting I wasn’t doing a whole lot of conditioning work but at the time I was doing my Masters, I was working with a whole bunch of other people.

In the weight room I was a grad assistant strength coach and they love to do conditioning on Wednesdays. So on Wednesday morning, we would go and run these stairs, and man, it was tough for me – being a power lifter and not running since I played football years before. And my HRV scores would just absolutely plummet after these sessions.

But after a few weeks I would notice smaller and smaller fluctuations in my scores and I was kind of reflecting the progressive adaptation for that training stimulus, and I thought that was kind of cool.

[Damien Blenkinsopp]: Right, so what kind of impacts do you see? So, once your score has plummeted, what does that mean the next day? Say you start the day and you track your HRV and your score has plummeted, what does that mean in terms of how you are going to be feeling? What does that mean in terms of how it is going to change the decisions you make that day?

[Andrew Flatt]: A low score can definitely be the result of a heavy training session. Unfortunately it is not that simple. One of the great things about HRV is also one of its downfalls, that it is a global marker of stressors, whether that is physical, mental, or chemical. So not always will you see a low score because of training, it can be brought on by other things. So you really need to be tracking other variables to really make a meaningful interpretation of what the data is telling you.

[Damien Blenkinsopp]: Right, so in the context of your training program, if nothing else changes it is kind of like that it then should be down to your training?

[Andrew Flatt]: Right, so I think one of the main things is are you an aerobic athlete? Are you an anaerobic athlete? Are you a team sport athlete? It depends on your training because what heart rate variability is, is it is a reflection of the cardiovascular autonomous nervous system. So for the most part, and especially within the research, it has predominantly been used with aerobic athletes and that is kind of who would most benefit from it.

I mean, resistance-training athletes, at this point it is all experimental to see what it is we are actually showing but it doesn’t necessarily reflect muscle soreness. It doesn’t necessarily reflect muscle damage or your neuromuscular abilities for that day, your CNS potential. It is a reflection of the cardiovascular autonomic nervous system, which is still a very important piece physiologically for being prepared for training.

So it is only one marker to consider the cardiovascular system is extremely important with the recovery process, with removing waste products, and so forth. So when the cardiovascular autonomic nervous system has kind of rebounded back to baseline levels or super-compensated to above, that would indicate that system is ready to go and it is more likely to be in a more adaptive state to any kind of physical stress.

[Damien Blenkinsopp]: Right, so you have mentioned that it is the autonomic nervous system and another thing that we often hear is that it is an indicator of vagal tone. What does that mean?

[Andrew Flatt]: So the autonomic nervous system, simply put, is divided into two branches – you have your sympathetic branch and your parasympathetic branch. The term ‘vagal’ is referring to the vagus nerve, which is essentially the parasympathetic branch of the autonomic nervous system.

You have parasympathetic innervation in the heart that essentially – in any kind of physiology class your professor will give you the car analogy, where if your foot is on the brake the car is not moving, and that is your rest and response. And the autonomic nervous system is taking care of all the things that we don’t consciously control – so our blood pressure, digestion, endocrine gland secretion, and so forth. And then when you take that foot off the brake you have that withdrawal of parasympathetic or vagal activity.

Then when you hit the accelerator all of a sudden you get that sympathetic output and that is going to actually increase heart rate and prepare you for any kind of stressful events, whether it is exercise or simple postural change from lying down to standing up. You have to pump blood to the brain so you don’t pass out and that is a sympathetic response.

[Damien Blenkinsopp]: Right, and another way I have heard it described it is that basically your parasympathetic is trying to balance your system so that the vagal tone is the ability for you to balance and respond to stressors around you. Is that another way you look at it, or is that not correct?

[Andrew Flatt]: Yeah, so essentially the sympathetic nervous system will be quite active during physical stress like exercise and then to recover from that is when your parasympathetic nervous system will help rebuild structures and repair the damage essentially that occurs during those stressful events.

So that is why measuring your parasympathetic activity on a day-to-day basis is a reasonably good indicator of your recovery status. If your body is still stressed from training and you have a higher sympathetic output or even just parasympathetic withdrawal, you know that your system may not be fully recovered.

Now, what I want to be clear is that it doesn’t mean that you can’t train if your HRV is a little bit low. And a lot of these apps, what I think people need to understand, is only measuring parasympathetic activity through a timed domain measured called RMSSD. So that does not give you any indication of sympathetic activity. It is purely vagally-mediated, so parasympathetic.

[Damien Blenkinsopp]: So just a couple of other terms that you hear quite a lot is LF, low frequency, and HF, high frequency. As I understand it they often say LF is the sympathetic stressor and HF is the parasympathetic relaxation. Is that true or is it more complex? Some of the apps track the LF and the HF as well, but some of them don’t.

[Andrew Flatt]: So the way you are talking about it, they are called spectral measures from frequency domain analysis. HF generally does indicated parasympathetic activity. LF actually would be indicative of both parasympathetic and sympathetic activity. So it is not as clear as we would like it to be, where HF is parasympathetic and LF is sympathetic and it gives you an indication of sympathovagal balance, they call it.

It isn’t that clear and one of the issues with the spectral measures that you are referring to is that in terms of their practicality and field settings, they require longer measurement durations for a valid assessment. These are less reliable markers on a day-to-day basis so it has kind of been recommended that RMSSD is the preferred parameter, especially for convenience and non-expert users in the field that just need a simple number that they can read and interpret real easily. The RMSSD value is preferred for that.

[Damien Blenkinsopp]: So is RMSSD the one that has the most research behind it?

[Andrew Flatt]: Well with RMSSD, the reason why it is preferred is that it is a more reliable marker. It is very easy to calculate. If you have R-R intervals you can actually calculate RMSSD in Excel – it’s a statistical measure, root mean square of successive R-R interval differences, that is what it stands for. It is consistent in paced or non-paced reading situations, where as HF and LF are going to be a lot more influenced by your breathing rate.

So, for in the field with athletes who may not be sticking to a certain respiratory rate or whatever, it is not going to affect your numbers as much. And lastly, I kind of got to it before, is it can be calculated in a relatively short time frame. In fact, you can get an RMSSD measure in ten seconds; however, that generally isn’t enough R-R intervals to capture a real window of that autonomic activity.

So actually part of our research was seeing what is the shortest timeframe we can measure HRV in with RMSSD and what we did was we found 60 seconds to be no different than a criterion measure, which has been established as five minutes. So we essentially randomly selected 60-second segments within a five-minute ECG and we found no differences. But when we looked at 30 seconds and 10 seconds there was less agreement with the five-minute measure. So our conclusions were that 60 seconds was probably enough time to get a valid HRV reading with RMSSD.

[Damien Blenkinsopp]: That’s great, that’s very short. A lot of the apps, you said, do a lot of the standard – I think it just comes from the research, which is five minutes for a recording. But a lot of the apps now are looking at like three minutes or something like that. What kind of variance do you see across the apps? Have you seen any apps that go as low as 60 seconds, making it a lot more convenient?

[Andrew Flatt]: Yeah, there are some apps – ithlete, for example, is an app that uses a 55-second test. There is another app call HRV4Training that uses – it actually allows you to select your test duration so there is a 60-second option. I believe there is a two-minute option, a three-minute option. And then I think there is a device called Tink that I believe is a 40 or 45-second test. I used that briefly. And the other apps tend to use a little bit longer.

Now, the longer measurement is certainly not a bad thing to get a bigger sample of R-R intervals for analysis. The issue comes down to is the athlete or the client – are you willing to do that every day? If it is two or three minutes, that can be a little bit long. Fifty-five seconds or one minute, that is generally not too bad. I find it more tolerable with the athletes I have used it with. Generally they can handle it, so it call comes down to preference, right?

[Damien Blenkinsopp]: Yeah, totally. So we talked a little bit about the apps. So I would like to dive into that because I know there are quite a few out there and there are a lot of them coming into the market now and HRV is just starting to become pretty popular. So basically you are going to have a device for tracking your heart rate and you are going to have an app to go with it. Which ones have you looked at and what are the tradeoffs and benefits of each? Have you got preferences and so on?

[Andrew Flatt]: So I first started out with the ithlete app. That was the one I read on the forums that people were talking about. In fact, I think it was the only one available at the time.

[Damien Blenkinsopp]: So when was this, by the way?

[Andrew Flatt]: This was 2011, early. I think around summer 2011 is when I actually bought it. So that specific device at the time required a heart rate strap and a little ECG transmitter/receiver device that you would actually plug into the headphone jack of your mobile phone. And again, it was a 55-second test and I have stuck with that device.

There are a few reasons why I have stuck with it, one being that it uses such short measurement duration. And especially now that I have looked at the data, I am quite confident that short of a duration is still going to give acceptable measures or more valid data. So I have stuck with that but I have used others. I have done some beta testing for some people and looked at some other apps. And at the end of the day you just want one that you are going to be able to use and that provides your data that is easy to interpret, nice visual trends, health, or whatever is more affordable for you.

There have been some advancements in technology that allow you to measure HRV without an ECG receiver. Now you can just use a Bluetooth heart rate strap with some of these devices. There was recently validated, a pulse wave finger sensor that ithlete is using that you can literally without any kind of heart rate strap you just plug your finger into this little finger sensor device that is plugged into the headphone jack and you can actually get your heart rate reading from the pulse at your fingertip.

[Damien Blenkinsopp]: How accurate do you think that is? Because I used one of those for something called Heart Math, which is using HRV but in a different area and that uses your ear. So it is collecting your pulse from your ear. But I find that every time I move in any little way that it is messing with the signal and it is not very clear. So do you find the finger sensor? Because it is using light, right? So it is pulsing light in to see what your heart rate is. Do you find that reliable?

[Andrew Flatt]: I think we have about 15 athletes where we looked at the pulse wave finger sensor and compared it to EKG. They were soccer players, male and female. We did supine and standing positions. And it was accurate. It was more accurate in the supine position but acceptable agreement also in the standing position. So we haven’t published that yet. We want to collect more data on it. But I am pretty confident in it based on the data that I have collected with it.

Now the pulse wave finger sensor device, that is not putting your finger over the camera lens – where the flash goes. That is not what we measure, just to be clear.

[Damien Blenkinsopp]: So if someone is getting one of these apps, what would be your suggestion? So all of them are using RMSSD, I’m assuming. I know the one I am using, Sweetwater HRV plus a Polar H7 strap, so the heart rate with the Bluetooth that you mentioned earlier for an iPhone 5. So that works fine for me and that was relatively cheap to get off and running with. So I know that Sweetwater, for example, they take RMSSD and they modify it a little bit. They put it on this 1-100 index. Do the other apps modify this? Are there compatibility problems later if you want to switch apps and you can’t compare your score?

[Andrew Flatt]: So Sweetwater, or the SweetBeat app, I have actually experimented with and that, from when I used it, was providing various HRV parameters. It was giving you the HF, the LF, RMSSD, SDNN – numerous parameters of HRV, which is great if you know what those mean and how to interpret them. But I generally tell people to look at the RMSSD.

I know when ithlete started using a modified RMSSD value what they essentially did was they logged transformed RMSSD and multiplied it by 20, and that gives you a figure on a 100-point scale. BioForce uses that value. I wasn’t aware that Sweetwater or that the SweetBeat device did or not. I thought it was a raw RMSSD value, but I could be wrong.

[Damien Blenkinsopp]: I actually spoke to them one time, so it is definitely a modified scale version of it.

[Andrew Flatt]: Okay, so then they probably use that value or something very similar. Now, not all apps use that value. For example, Omegawave has a smartphone app and they are using their own algorithm to come up with a daily readiness score, so they are factoring in HF, LF, the HF-LF ratio, RMSSD, so it is not one parameter that they use. So there is difference among the apps and what they interpret. So it is something you would probably want to look into.

[Damien Blenkinsopp]: Right, and you probably don’t want to switch around too much once you have settled on one.

[Andrew Flatt]: Right, you find an app that you like. What is most important for the end user is I think the visualization of the data and how they can view it so they can see what their kind is like, how it is responding to their training. One of the things I really appreciate about the ithlete app is that it allows you to input your training load score, so depending on what kind of training you are doing or how you choose to quantify your training load you have your RPE values and you can calculate tonnage for weightlifting or powerlifting.

You can do a trim value for endurance athletes or what have you. So you can input a training load value and then it also gives you the ability to track your cyclometrics, you perceived level of stress, sleep quality, muscle soreness, mood, your nutrition. There is a sliding scale for that you can kind of rate. So all of a sudden you have a device that isn’t just tracking your HRV but it is kind of monitoring several variables which really makes interpretation of your HRV trend more meaningful. I know BioForce has an online system where you can go on, input your data similar to the ithlete one.

I am not sure if you can do that from the app or not at this point but it is a very similar system. So that is another great product to look into. So when you are evaluating what app you want to use, you want to look at what additional features it has to offer because an HRV score by itself is less meaningful without all this other information. So the more information you have and that you can maybe attribute your changes and your trend to, the better off you are going to be.

[Damien Blenkinsopp]: Right, I know for me there have been a few times where there has been a huge crash and I have been wondering what happened. I didn’t have a big training session or anything yesterday, so it is definitely like this little investigation sometimes – why did my HRV crash? I know you have got some interesting stories about times that you have seen athletes or your own scores crash. What kind of things have you seen the influence where it crashes? Have there been any times where you really didn’t find any reason for it?

[Andrew Flatt]: I mean, if we are talking a substantial decrease in your score, usually it is pretty easy to attribute it to something. Sometimes it is these smaller deflections where you are like, you know, I am kind of surprised it is that low today. That may be harder to attribute to something specifically. But if you wake up with fever, you are going to have some real low scores and your heart rate is going to be high and you are going to have some low scores.

One of my coolest little anecdotes that I have with using an HRV app is when I got real sick a couple years ago over March break and HRV I was able to use to guide my training to where I could kind of start pushing it hard again and kind of get back to my normal routine.

For a week I had terrible symptoms. I had fever, I wasn’t able to train. My scores were really low. Once my symptoms kind of subsided and I wanted to get back into training, what I was seeing was from very moderate workouts, very low-intensity, something I would consider like a D-load type of workout, these were causing pretty substantial decreases in my HRV so I could see that my body was reacting to the training. But it was quite stressful, according to those scores.

So I would actually continue to train relatively light until my scores wouldn’t fluctuate so much and that is when I would actually start pushing harder again and I could see in my trend that it wasn’t as stressful. I wasn’t seeing as big of swings in my scores and I was kind of able to guide myself out of that situation where typically a meathead like me, I will just start pushing the weight as hard as I can as soon as I feel ready, which may not have necessarily been the best thing to do at that time.

[Damien Blenkinsopp]: Right, totally. I have been in similar situations myself. I know I had a score of 80 just recently and it crashed to about 50. I don’t know if that something you see often?

[Andrew Flatt]: Yeah, that’s a big drop. Were you able to attribute that to anything?

[Damien Blenkinsopp]: Yeah, I have been suffering from a chronic illness and it has something to do with that, so it is pretty serious. It is a pretty serious thing, it is not a typical thing. So in terms of someone a bit more normal, who is not dealing with medical issues or anything, what would a typical rash look like? Is it 20 points?

[Andrew Flatt]: Everyone is individual and unique. Every individual’s data needs to be taken in the context of what kind of training they are doing, how advanced they are, how trained they are. A more advanced endurance athlete, for example, will see smaller swings more than likely. They will recover faster.

You take an untrained individual and you put them through an intense workout, whether it is weights or conditioning, and they are going to see a big drop. That can last for 48 to maybe 72 hours. So every situation is unique and every individual really needs to take some time to collect some data and observe how their trend is evolving in response to their training because unfortunately you can’t just say that this means that for everyone, because that is just not the case.

And you really do have to maybe do some calculations with your data in Excel, looking at the weekly mean value. You look at the variance within that week and all that kind of analysis will give you a better indication of how you are responding to your training.

[Damien Blenkinsopp]: So of course, a lot of the other things that athletes look into when they are training are all sorts of lifestyle factors that could be affecting their recovery and how they are performing. I know that you have had many experiences with this and in one post you talked about travel and in another you talked about going home for was it Christmas or Thanksgiving? And seeing some stuff there.

What kind of situations have you seen – like another guy who went on Spring Break and he was partying a bit? What situations have you seen that could be said to be obvious, but what kind of things would you say to look at? Just typical things that you have seen affect it.

[Andrew Flatt]: Yeah, so your lifestyle absolutely will affect your HRV responses. For example, working with a soccer team, we put them through a hard week of training and we see pretty typical HRV responses and then half of them go out on Saturday night partying, maybe having a couple of drinks, I don’t know. And the other half maybe stays at home, gets to bed at a reasonable hour, and you can definitely kind of predict who was out that night based on that.

Now, you definitely would need to do a little bit more investigation. You can’t just look at a score and say, ‘This person did this.’ But it does give you some kind of indication that maybe you have to look into what is going on. Was it the night before a game? How are your athletes behaving?

Not necessarily a tool to spy on anyone or anything, but it kind of will lead to some questions. Why isn’t this person recovering? Why are their scores low? Are they getting sick? Are they staying up too late? Are they not getting enough sleep? Sleep is definitely one factor that will affect your score. Alcohol – if you are out drinking you are definitely going to see some lower scores the next day.

Like I said before, with illness your scores will definitely drop from that. In my experience any time I have gotten a cold or especially a fever, the score has dropped. Now you were referring to some of my older posts where I talk about I actually went home to visit some family that I get to see maybe once or twice a year. And I actually had really high scores the next day. Is that the reason why they were high? I don’t know, that is just speculation.

But anything that you perceive to be very restful, whether that is sauna, you get a book and read outside, get some sun – something that you perceive to be restful and relaxation is generally going to promote some of that parasympathetic activity and that restoration that we want to get. So I think it depends on the individual and their own personality for what they perceive to be regenerating and relaxing.

[Damien Blenkinsopp]: Well certainly sometimes I will take a specific day off and say okay, I am going to recover this day because I need to because my HRV is down. And it definitely pushes the score up, I have seen that many times. So like you say, the relaxation could be different for different people. But it definitely seems to impact the score if you take a day off and forget the work and all the other stressors. I don’t know if you have seen examples of work stress figure into this?

[Andrew Flatt]: I have seen some studies. I am not as interested in that so I don’t pay too much attention, but there is definitely a stressful lifestyle, whether that is from work, you can have money problems. These are all things that can affect your autonomic nervous system. So it can be apparent in your HRV score. One thing I found is just within the literature but also through trial and error, that some light aerobic work has a stimulatory effect on parasympathetic activity. So some active recovery can really help get people’s scores up.

In fact, just a few weeks ago I was going through kind of a work capacity phase where I was just trying to get in better shape, bring up my aerobic fitness a little bit, so after my resistance training sessions I was doing 10 to 15 minutes on the bike, on off days I was doing 20 minutes on the treadmill or 10 minutes on the treadmill and 10 minutes on the roller, just trying to increase my fitness a little bit. And I have actually never seen anything like it in my trend before.

I wasn’t seeing any really big swings from day to day, even after a heavy resistance training session with five sets of five with 80% plus. Normally that would result in a lower score the next day but it appeared that these smaller aerobic sessions really attenuated those swings day to day so I was seeing very little variance between my scores for that two-week period, but then as soon as I stopped keeping up with that it went back to my old-fashioned hard workout and you see a lower score and it takes a day or two to come back up.

So it is interesting how much of an effect just light aerobic exercise has on stimulating that parasympathetic activity. There is definitely a threshold where too much or too intense and it will have the opposite effect, but a reasonably late session for not too long generally has a stimulatory effect and you will see a bump in your HRV 24 hours later or so.

[Damien Blenkinsopp]: So are you saying that is something that is going to help people? Or is this just modulating the HRV but it is not going to impact your actual recovery? So it is just modifying the number but it is kind of hiding the fact that your HRV would have gone down?

[Andrew Flatt]: Well, I think again it comes back down to what your training goals are. Now after a heavy squat session and I do some cardio, some light aerobic work after, and I don’t see a drop in my HRV, that doesn’t mean I am going to be able to go squat heavy again necessarily. It is just saying that my cardiovascular autonomic nervous system has rebounded back to baseline level, so that system may be ready to go again. So again it comes down to context.

If you are more of an endurance athlete it would probably be more of a marker of when you are ready to train again, but with resistance training there is muscular damage. That isn’t necessarily reflected in your HRV. There is just not enough data yet to show that an HRV score is related to any kind of nervous system potential for strength scores or power or anything like that.

[Damien Blenkinsopp]: That is interesting because one of the things you mentioned was that when you are doing something new, some kind of new activity, some type of new training, that you see your score crash down in particular in those situations. Is that – do you think it is because of neuromuscular or metabolic adaptation that has to take place there? What do you think that is down to?

[Andrew Flatt]: Probably a combination of everything. You have introduced a novel stimulus that your body hasn’t necessarily adapted to yet or in a long time so it is just harder to recover from. I don’t have the answer for that. It hasn’t really been, at least I haven’t seen anything to explain why – that is just how it is. A novel stimulus, whether it is conditioning, resistance training – if you do a drastic change in your volume or intensity, from what I have seen it is going to cause a lower score than typical. But with persistence and that new training modality or those methods you will see that progressive adaptation and you will see smaller swings after the body kind of adapts. It gets more familiar with it. There is probably a better scientific explanation, I just don’t have it for you right now.

[Damien Blenkinsopp]: Great, so I want to talk about recording – how you record it, what kind of numbers you want to make sure you get, frequency, and so on. But just before that, how about baseline? Can you increase your baseline over time? Or are we just looking kind of like at the dips and the highs and trying to keep it in the highs more and slacking off when we have more of the dips? Or are we able to actually influence this and in a way build more resilience over time?

[Andrew Flatt]: Your lifestyle is going to change, your training is going to change, your training frequency. If you are a competitive athlete that you have different seasons, different times, that is all going to affect your HRV because your training is going to change. You are not going to always be doing the same type of training. You might be doing less aerobic work in a different phase and that aerobic work is really what stimulates those higher HRV scores.

So if you are doing less aerobic work you are going to see lower scores. So you do have to take whatever your baseline is – you have to take it into context for that training phase and your new training goal, so you absolutely have to have an evolving baseline. A lot of the apps will use a rolling 7-day average but generally at the start of a phase you look at your first week, you look at the average, you look at the variance within that week.

A simple value to use is called the coefficient of variation. It is just the standard deviation divided by the mean times 100, and that gives you a percent value of the variance, and see how it evolves from there.

[Damien Blenkinsopp]: So what do you use the COV for?

[Andrew Flatt]: So the Coefficient of Variation is where you have a weekly mean value, which is just the average of a 7-day period. That average doesn’t necessarily indicate or reflect how much fluctuation existed between those scores on a day-to-day basis, right?

So we want some kind of value or figure similar to a standard deviation of how much variance there was because let’s just say your average between two weeks is no different, but you have much more fluctuation in one week than the other – well, that could be indicative of some positive adaptation or I have a case study that we did with a cross country endurance athlete that should be published in one of the next editions of Australian Strength and Conditioning.

We actually found that his CV value, the coefficient of variation, was much more related to his endurance performance than his weekly mean value. And we get into possible explanations of why in the paper but the variance is important.

[Damien Blenkinsopp]: So you want less variance, which means that your system is dealing with the different stressors and it changes more easily?

[Andrew Flatt]: I don’t think – I think it is a matter of maybe when you want that. If you are seeing big fluctuations in your scores that is not a bad thing. That is your body adapting and adjusting to the training. But that probably means that you are not in the best state to compete at your best or to perform at your best because your body is adapting and it is going through the stress and recovery phases.

But all of a sudden you have been doing that training for a while and you see less fluctuation in your scores and there is maybe less – it is not the same amount of stress as your body initially perceived it as and had you recover from. You may be in a situation where your performance – you may be at a higher level of performance.

[Damien Blenkinsopp]: Yeah, it sounds like COV low variance could mean that you have adapted to whatever stimulus you are giving yourself, and that could be lifestyle or it could be training. And in another situation if it is pretty high it could mean that something different is going on and your body is adapting to it.

If it has got high variance it could be a good thing if you are going through these training sessions. It is showing that your body is going through that adaptation, does that makes sense?

[Andrew Flatt]: Absolutely. And one thing I need to point out is I started using the COV value after reading a case study by Daniel Plews and Martin Buchheit and all those guys that are the experts in this area. And what they found with the CV was in an overtrained, high-level endurance athlete I believe the CV was related with the progression of overtraining.

So when you are looking at any kind of value, whether it is the mean or the CV, you really need to look at the training load. You need to look at their perceived levels of fatigue and stress to really give more meaning to that value. So again, a high HRV score or an increasing trend can also be indicative of overtraining and mostly in endurance athletes. So you kind of have to look at these other factors.

The HRV scores alone aren’t going to tell you much without all this other information. So the CV, whether it is good or bad or whether we want it or not depends entirely on the context of that training and what is going on with the athlete and how far we are from competition, so there is no such thing as we want this, maybe in certain phases we want this, but it is all relative to the individual and to the training, so everything needs to be factored in.

[Damien Blenkinsopp]: If you take two athletes or perhaps an athlete and a non-athlete and you compare their HRVs, their 7-day average right and getting their baseline, are they going to be different? Is the athlete’s going to be higher? Is that something like going back to your baseline, is that something you want to be higher or you should be trying to get higher over time. Is it possible?

[Andrew Flatt]: I mean, the average person, just for the cardio-protective benefits of having a higher parasympathetic activity at rest definitely generally higher HRV is a good thing. If you take a team of athletes and you have them monitor their HRV, you are going to get different scores and a group of female soccer players that I work with over this past season, their average scores range from the low-70s up to a couple of girls that were pushing 100.

There is a genetic factor here. There is lifestyle, there is fitness. All these things come into play and you can maybe generalize that an endurance athlete who has a very low resting heart rate is going to have higher HRV, which can be in the 90s plus anaerobic athletes can be between the 70s and high 80s, depending on their fitness level.

So you could maybe say that this would be where the average would be for this type of athlete, but in my experience everyone has kind of have their own trend and their own response to training – similar responses in terms of the fluctuations in following a heavy training day and whatnot. But you are not going to get a team of soccer players with everyone’s score at 90 with similar changes, everyone is different. And you should plan accordingly for that.

[Damien Blenkinsopp]: Right, so for someone in the 60s, is that okay? Or someone in their 50s?

[Andrew Flatt]: Well, I mean I would ask if that is being measured in a supine, lying down position or if that is a standing value, because that obviously will make a difference.

[Damien Blenkinsopp]: Let’s get into that then, because I know you take both readings, correct?

[Andrew Flatt]: Well, I have experimented with both. I have been sticking with standing – I had been doing it standing since day one but I did an experiment for a little bit and actually at different time points I experimented with supine readings as well. So you want to get into –

[Damien Blenkinsopp]: So I mean, supine just for the guys listening – that just means you are lying down? So you are taking readings when you are still in both situations, right?

[Andrew Flatt]: Correct.

[Damien Blenkinsopp]: So we are getting into sort of recording methodology here. How do we go about actually taking these readings and when would you do it to get reasonable results? I take it, for instance, every morning when I wake up and I will take the lying down one and then I will stand up and take that. I have to let it rest for a little while, so I will stand up for about a minute and then I will take the reading.

So you can tell me if that is like correct or not. I seem to get relatively stable readings. How would you go about it now? What kind of things have you discovered that are good and bad and help to get and what kind of things do you need to avoid?

[Andrew Flatt]: Well, it’s interesting. The general guidelines are a supine measurement where you record the last five minutes of a ten-minute segment, so you essentially have what I often call a stabilization period where you let your heart rate adjust to that position.

So that is generally a five-minute period followed by a five-minute recording. You know, with the research that I have been doing at Auburn University with Dr. Michael Esko is trying to investigate shorter, more convenient HRV recording procedures because one, we want to do research with these smartphone apps but we weren’t entirely sure if we were going to be able to publish anything without any kind of validated shorter measurement procedures that we could say, ‘You know what? We did a shorter measurement recording. We had a shorter stabilization period.

But that is not necessarily a problem because it is not really showing any differences to these accepted standard measurement procedures. So as I kind of mentioned before we found that 60 seconds was a suitable duration for an RMSSD measurement. We have a new paper that is currently in review where we looked at how long does this stabilization period need to be, at least in a supine position?

So we looked at a standard measurement – five minutes following a five-minute stabilization period. And we just looked at if each individual minute – you know, minute one, minute two, three, four, and five – were those values any different to the five to ten-minute segment? I am not able to reveal the results but I am pretty confident that we can get away with a shorter stabilization period, much shorter than what is traditionally recommended. And we are just looking at capturing a resting measure and we are not using this for clinical diagnosis or anything like that, right?

So in healthy populations in athletes where we just kind of want to get a general indication of their heart rate variability that day and we don’t need a whole ten-minute procedure.

[Damien Blenkinsopp]: So what is the statistical variance we are talking about between yours and the five-minute one? Is that 5% difference?

[Andrew Flatt]: Are we talking about the stabilization or the 60 seconds?

[Damien Blenkinsopp]: Yeah, if you do your shorter version. Which is one minute and one minute?

[Andrew Flatt]: Let’s just say that you use a one-minute stabilization period and then a one-minute test. I mean, you are trying to get me to get into the results, which I shouldn’t do until it gets published.

[Damien Blenkinsopp]: Just a rough idea. You said it is okay, right? Don’t give me a statistic yet.

[Andrew Flatt]: Let me putting it this way, it would be trivial. That’s the term we use with that statistic called the effect size, which is telling us how practically meaningful the difference is. The shorter stabilization period as opposed to the traditional one, you would probably see trivial differences.

I could tell you within the literature a five-minute HRV recording has been used following only a one-minute stabilization period and that has been used in elite endurance athletes and the data was still providing very meaningful information pertaining to training status so again, a shorter stabilization period of one minute has been used so I would say to go ahead and use the one-minute stabilization period.

[Damien Blenkinsopp]: So it sounds like it is reasonable to do a one-minute stabilization and a one-minute – depending on the app they do different times or automatically of course, but you think that would be okay for some guys at home who want to use this for training and so on?

[Andrew Flatt]: I mean absolutely. With the athletes I work with and with myself and then with the data that we collected and looked at, the one minute is not very different from the five-minute value. So yeah, I am quite confident in that shorter measurement with RMSSD, specifically.

[Damien Blenkinsopp]: Great, so what other things – are you still taking the lying down, the supine, and the standing – and the one we have just spoken about, the one minute, one minute, is that just fine for both of them?

[Andrew Flatt]: Yeah, after a postural change what happens is in the supine position your heart doesn’t need to work as hard to pump blood to the brain. Then you stand up all of a sudden you have receptors that are going to detect changes in blood pressure and this happens real quickly, but essentially your heart rate is going to shoot up real high immediately following a postural change.

And then it actually takes longer than a minute to actually stabilize, but in the research one minute following that postural change is when they will start recording HRV in the standing position. Going back to why I like the standing measurement, it is simply because what’s happening is you are introducing a small stressor to the body that it needs adapt to. It is called orthostatic stress, when you stand and put that little challenge on the heart where it has to react to the postural change and then you essentially are evaluating how your heart is responding to that.

If your heart rate variability is very low after you have given your heart rate time to stabilize, that may be a better indication of how your body is going to respond to physical stress that day. That is kind of a working theory. And that is nothing new. I am not sure if you are familiar with what is called the Rusko test, where you start by measuring the heart rate lying down and then you measure it following a postural change at different times, and you are trying to see what the changes are between those. So it is not a new concept and certainly nothing that I can take any kind of credit for.

But I did experiment with taking supine and standing measures and seeing how it related to my previous day training. This kind of unequalled one experiment – I have always found that the standing position provided a better reflection of my perceived level of recovery with yesterday’s training. That is not a very scientific method and I didn’t take any blood markers or anything like that but just from visualizing the trend I see that the standing position looks how it should, based on how it is feeling and what training was like the previous day. So I have pretty much stuck with that.

[Damien Blenkinsopp]: Okay, so now do you use just the standing or do you use both?

[Andrew Flatt]: Yeah, my preferred position is seated or standing. I do standing just because it is practical. You wake up, you go pee, you are already standing. I use the finger sensor now, so I plug in the finger sensor and I do my measurement right there in the bathroom. It is just easy.

The seated position would also be similar to provided that. You are obviously going to have to sit up and there is going to be that little orthostatic, that seated up, more vertical position challenge. So the seated position is probably – I wouldn’t think it would provide significantly different in terms of at least the trend. The number value might be different but the trend would probably be the same.

[Damien Blenkinsopp]: Do you see more variance and slightly lower numbers for standing versus supine, or lying down?

[Andrew Flatt]: Absolutely. The supine values are going to be much higher. I have data on the soccer team I have been working with. I had them do supine and standing measures because that is a question I have always been very interested in – what is the better position?

Some preliminary analysis on the data – I think what we’re seeing is that without getting too much into the results I think supine and standing may be potentially indicating some different information where supine may be related a little bit more to fitness and standing may be more related to the acute changes in response to previous day’s training.

Again, that is very preliminary and we have still got a lot of analysis to do but from that data that is kind of what I am seeing. From my personal experience –

[Damien Blenkinsopp]: So what you are saying is that lying down is kind of like your baseline and standing is what has been going on the last week in terms of what you have been up to and exposed to in terms of stressors?

[Andrew Flatt]: Possibly. It is hard to draw any kind of conclusion. But in the supine position in very fit athletes there have been issues of parasympathetic saturation, but all of a sudden you sit up or you stand up and you kind of eliminate that issue. So I know in a recent paper by Stanley Peak and Martin Buchheit where it was in sports medicine and they reviewed the literature on parasympathetic reactivation after exercise. And one of their recommendations was to measure in a seated position.

I would definitely recommend anyone, especially exceptionally fit athletes – any endurance athletes or some really fit athletes like soccer players, rugby, or what have you – with really low resting heart rates. I would definitely do either a seated or a standing position. For less fit individuals with higher resting heart rates, the supine position may be fine. That is a gut instinct and I don’t necessarily have the kind of data to support that. So take that how you want to.

[Damien Blenkinsopp]: Okay, a few of the other things – just to make sure there are no other confounding variables coming in here – do you have to make sure this is at the same time of day, or is that irrelevant?

[Andrew Flatt]: Actually yes, I meant to get into some of this stuff. You definitely want to be consistent with your measurement procedures. One of the best recommendations is you have to remain as motionless as possible. It is funny, you collect ECG data on a bunch of athletes and you are reviewing it and you see some funny things and you are like, ‘Man, what were they doing in there?’ And one athlete had a bit of a cold at the time and we could see her sneezes in R-R interval trend.

On the tachygram we could see when she sneezed. We could see when athletes moved positions or adjusted their position. This all is going to affect your heart rate. I looked at an ECG trend when the investigator walks into the ECG room, or the lab, and just that startles the subject or it might not startle them but it does provoke a heart rate response and all that can affect your heart rate variability information.

So you want to be as undisturbed as possible. You want to limit any kind of noises. You want to limit anything that can be distracting. You obviously don’t want to necessarily check your emails or messages first thing before you do it because that creates an anxiety based on work-related issues or anything really.

So you definitely just want to wake up, do your business in the bathroom, empty your bladder, and do your measurement, whether you do it seated or standing or if you choose to go lay down again. Or if you choose to just do your measurement right in bed after you wake up, you know. Consistency is the most important, definitely limiting the noises, like I was saying.

Time of day is a research question that we have and that is something we want to answer. There is definitely going to be circadian rhythm effect so if you do a measurement at 7 a.m. it is definitely going to be different by noon. But is there a difference between a 7 a.m., a 9 a.m., or if you are within a reasonable time?

We have been asked by some professional NFL teams if they can bring their athletes into the workout facility, have them lie down on a training table, and do their HRV then, as long as they control for all the other variables. My assumption is that it is not going to be the same information you are getting from a waking measure, but how different is it and can we still get some meaningful data from that? I don’t know – that is something we definitely want to look into.

[Damien Blenkinsopp]: So the whole thing about doing this first thing in the morning is it manages to eliminate a lot of potential confounding variables like what is going on in your environment, what you have been doing in the morning, anxiety, and all these other things.

[Andrew Flatt]: Yeah, and apart from sleep it is going to be your most rested state, right? So that is the ideal time to do it.

[Damien Blenkinsopp]: So some of these apps also correct for things like arrhythmias, errors, artifacts, ectopic beats, and a bunch of things which are kind of noise. Would some of them, like I know the Polar kind of automatically does that. I am guessing that some of the others do. Does this eliminate these kind of things we are talking about to any extent or not?

[Andrew Flatt]: Yeah, because we did a cross-validation with the ithlete device and we looked into how it goes about interpreting the data. And actually that device particularly has thresholds for R-R intervals where basically the average highest range for an R-R interval versus the lowest range, if you get a series of R-R intervals that kind of exceed that threshold, either above or below it, it is going to correct for it with the adjacent normal cycle.

So a lot of these apps will have built-in irregular beat detection systems. Again, whether it is the R-R interval that is way longer than average or way shorter than average, it will essentially pretty much red flag that as an irregular beat or an artifact or what have you, and correct for it. And that is a limitation of a shorter measurement.

If you are doing a 55-second test and if you experience a couple of ectopic beats, generally within a one-minute period you should be experiencing more than one. But the shorter measurement duration, that is a shorter series of R-R intervals, and there is more room for error in that situation. But like I said there is that irregular beat detection function. When we have compared and I think we had 25 athletes where we compared it to ECG and it was accurate, and that small sample of people didn’t have as many issues.

[Damien Blenkinsopp]: Right, great. So is there anything else in terms of recording that you have to be careful of to make sure the data is useful and current and so on?

[Andrew Flatt]: I think the key is that you want to be able to do this every day and you want to do it consistently for meaningful data analysis and the key is to just make sure you do it and you are consistent in your environment and where you are consistent in your position.

You don’t want to stand one day and do it seated the next day and then supine. If you want to experiment, when you do a measurement save it in your preferred position and just log your other position measurement. You don’t want to save it so that it affects your trend line by any means.

So the key is being consistent in your position, being persistent if you choose to do the paced breathing. Some of these apps provide paced breathing. A lot of them will give you 7.5 breaths per minute, which was kind of the mean breathing frequency of a group of endurance athletes.

That is kind of where that value came from. Just be consistent and don’t do paced breathing one day and then not the other. It shouldn’t have too much of an effect with RMSSD but you do want to be as reliable as possible with your procedures. So either do spontaneous or paced breathing, pick one or the other and stick to it. Stick to the same position.

I am not going to like, I don’t necessarily measure at the same time every day. I mean, my lifestyle changes and I will be able to sleep in on certain days. I might have to be up super early one day and I do it when I wake up. That’s just the way life is, right?

Some people take it pretty seriously and they wake up at the same time every day and that is great. That would probably be more reliable but you have got to be reasonable.

[Damien Blenkinsopp]: Great, so what I do, for example, is I track it every single morning and I am looking for either acute drops, like big changes to take notice of. Otherwise, I am kind of looking mostly at the seven-day average. How do you approach this. Ideally I want my seven-day average to go up over time so that I feel like I am getting somewhere with things. How do you look at it? What is most important? Are you looking mostly at the seven-day average? Are you looking at the day-by-day? What are you using most in your actual decisions?

[Andrew Flatt]: Well, I like to look at everything. I like to see the acute change of what happened between today and yesterday. I do not generally at this point in time use a daily change to be a huge determining factor in my training, specifically because I am more of a resistance-training athlete.

I am involved in powerlifting, so an HRV score isn’t necessarily indicating if I am going to be stronger or anything like that. But I do take a look at it and I see and I always like to compare it to what happened the previous day. What I like to do is look at the weekly average and the variation of the previous seek, just to see how that corresponds to my training plan. If I had a higher-volume week where I was trying to create some fatigue, I would expect to see a lower average and maybe some more variation and go from there.

[Damien Blenkinsopp]: But if you didn’t you might say, ‘Okay, well I have been undertraining and I want to push a little bit harder this week.’ Is that the case?

[Andrew Flatt]: Yeah, I mean you can use that to guide how you may structure your next training cycle. Again, it really does depend on what kind of athlete you are. But for resistance-training purposes, I just do a lot of personal experiments.

I went through a phase where I was using the acute changes to guide my daily training, so rather than taking a – I would work three weeks harder and deload every fourth week. I stopped doing that for a bit where I would just reduce training loads on a day with a low HRV score, should that happen on a training day.

Training like that was fine and I made reasonable progress. I didn’t find that not deloading was an issue. Every fourth week by just taking off a day here and there or reducing loads. That was fine.

The issue is if you really want to make any kind of marked improvements you are going to have to do some overload training. And if you are doing overload training you are going to accumulate some stress. And you are probably going to see a decreasing trend in your HRV and that is generally not a huge issue. You just want to be mindful that you are starting to accumulate some fatigue and how long you want to persist with that. You want to pay attention to soft tissue issues. Are you getting a lot of inflammation? I would get some tendonitis in my elbows and so forth. So you use it as a guide but you take it with other parameters as well, like I was saying before.

Again, an endurance athlete would be a little bit different. I would actually probably use HRV – the acute changes. I would probably use that a little bit more to influence my daily training just because it has been shown that HRV-guided training with endurance athletes, based on your parasympathetic activity, you may be in a more favorable position for training for endurance exercise. So again it all comes down to what kind of athlete you are, what kind of adaptations you are trying to create.

[Damien Blenkinsopp]: Yeah, great. So looking at potential alternative metrics, another thing that people use a lot is resting heart rate. Is that something you would use as well or do you find HRV better? Is it ever worth taking both and looking at them in conjunction or do you think – what have done? Or do you have any experience with that, at resting heart rate?

[Andrew Flatt]: Well I think that resting heart rate is a little bit more crude of a measure. That is – now, although it is a little bit more prudent it can still be very effective. In fact, if you look at your RMSSD trend against your heart rate trend it will generally be a nice inverse relationship between them where they will kind of mirror each other. I personally don’t monitor both. I mean, if you don’t have an HRV device I would definitely do heart rate. I mean, that is something you could do by just measuring your pulse every morning. In my experience I just use the HRV value. What I want to do with the data we collected in the soccer team is see if the heart rate variability provided more meaningful information than basic resting heart rate alone. Do we even need heart rate variability? Even though it can be more specific of a measure, is it necessary? I don’t think that people need to dismiss heart rate and think that it’s not useful because it absolutely is. There has been good data on it and again, your heart rate variability trend with RMSSD isn’t going to be too dissimilar from your resting heart rate trend, it is just kind of inversely mirrored, you know?

[Damien Blenkinsopp]: Actually a couple of things, confounders I forgot to look at but I think are important. Our age and our gender, do they influence?

[Andrew Flatt]: Absolutely. What you will find as individuals approach middle age or they start to get a little bit older there is going to be a natural decrease in parasympathetic activity; however, that can be changed with training. So if you are doing regular aerobic work you can mitigate those decreases and have reasonably high HRV on a regular basis; however, I would assume that would change if you should stop keeping up with that kind of training, but absolutely. Generally what you will see is older individuals will have lower resting heart rate variability. Females tend to have – if you have two sedentary individuals the female will generally tend to have higher – that is not always the case.

In our data we looked at 20 endurance athletes – 10 males, 10 females. Their resting heart rate variability was not statistically significantly different so we measured them and compared them as a group rather than by gender. So if you are endurance trained you are going to have higher heart rate variability generally, whether you are male or female. But when you remove the training factor females will generally have a higher resting heart rate variability versus males – but again, that is not always the case, just generally.

[Damien Blenkinsopp]: I would like to talk a little bit about where this is all potentially going. In the future are we going to be able to do different things with HRV? Because I do know that it is getting more popular and there are more apps and devices coming out. What do you see happening with HRV over the next five years? Do you see it getting more sophisticated? Are a lot more people using it in different areas? What do you see?

[Andrew Flatt]: Well definitely in the clinical setting with regards to cardiac rehab guiding training of individuals who have had cardiac events and so forth, I am not as interested in the clinical side but that is kind of where a lot of this came from and started. So there is going to be a lot more usage of HRV in those situations, especially when we have validated mobile technology where you can acquire a resting score in a reasonably short period of time. I see it growing there.

One way that I see it being included in athlete is with reduced requirement, a lower frequency of measuring. So for example there is a recent paper that showed that less frequent measures of only 3 times per week was suitably reflective of the weekly mean value. So it didn’t necessarily need the seven-day value. You can get away with three when you are looking at the average.

One thing we are looking at with our data in the soccer team is how few days can we measure HRV where the mean value and the coefficient of variation are no different. So if we get more data on that and we start to realize that we don’t need to measure HRV every day if you are looking at the means and the CV. It becomes more practical and they are affordable. It was previously cost-prohibitive to measure HRV. You needed either an ECG or an expensive device. You needed an experienced and qualified technician to operate the device or the machine and then interpret it. Now within two minutes or less you can get an HRV score. An athlete can take it home and figure it out. It is real easy to do interpretation. Again, with the visualization and these other factors it is becoming a lot easier to use. So it is becoming more feasible for people and it is more affordable. So I can see it being definitely more widespread in sports, especially for any endurance athletes or soccer teams that currently aren’t using it. There are definitely plenty. But I think the more evidence that comes the more likely they will be to use it. Even the fact that we can now acquire HRV with a finger sensor makes it a lot more practical for an athlete to wake up and do the measurement.

If you think about it, a one-minute test is not that hard. But you would be surprised how many athletes can’t seem to do it every day. So reducing the measurement requirements to fewer days per week and making it easier to acquire the data, that is just going to increase the usage of it, I believe. It will at least increase the research where we will have more data to see if it is even worthwhile using in a soccer team or in a football team, and whatnot.

There are other areas where HRV is being used in the biofeedback where you are adjusting your heart rate, trying to increase your HRV prior to – there have been studies looking at baseball batting, golfing to see if it affects how accurate they are with their putts and so forth. That is not an area I am involved in by any means but that is where it is used.

[Damien Blenkinsopp]: Right, and I would say that some people have been connecting that to the flow stake, which they say is the high-performance stake. So the idea was that a higher HRV would mean that you are accessing your flow and you are more in a flow state than having a lower HRV. So I think that is some of the thing around that. I don’t know if you have seen that?

[Andrew Flatt]: Yeah, I have looked at some papers. My interest has always been in a resting measure and how it relates to performance and fatigue and so forth. But that research is progressing so who knows where that is going to evolve. But again, it is just a matter of having more published data to show that this is how it can be used. We are pretty clear that it is pretty effective but how practical can it be in the applied setting with a team of athletes and so forth is the next question.

[Damien Blenkinsopp]: So where is a lot of the research on this and which journals do you find it in? Are they in some specific journals or is it sort of scattered around? Have you seen it increasing over time?

[Andrew Flatt]: There has definitely been an increase in the amount of research on heart rate variability for athlete monitoring purposes and so forth. Just to name a few journals you are looking at International Journal of Sports Physiology and Performance.

There have been some in the European Journal of Applied Physiology. Every month there are one or two of these papers in a lot of these sports and science journals every month that pertain to heart rate variability. Journal of Sports Sciences, European Journal of Sports Science, Journal of Strength and Conditioning Research, so yeah – I kind of go through these every month and see what has been recently published. You can get on Twitter and follow a lot of these researchers and interact with them and sometimes they will give a heads up on what is coming and you can discuss it with them. Attending conferences, you can kind of see what research is upcoming, what is being done.

In fact, that is how I got into all of this. I attended the National Strength and Conditioning Association – their national conference in 2012. And that is where I met my colleague, who I have been working with for the last year or two, Dr. Michael Esko. He was presenting a poster on HRV and he was the only on there doing any HRV research. He was living in Alabama, I was living in Toronto. We hooked up and the next thing I knew I was moving to Alabama and we started doing research together.

[Damien Blenkinsopp]: Great, so who else might this be – you may have already answered this. I know you mentioned a few names, but who besides yourself would you recommend to follow to learn more about HRV and these biometrics?

[Andrew Flatt]: Well definitely Martin Buchheit. You can find him on Twitter. Daniel Plews, who worked with Dr. Martin Buchheit. Jamie Stanley, another guy who has been producing some great HRV research. Fabio Nakamora, Joel Jamieson, who kind of runs the BioForce system and the 8 weeks out website.

The ithlete has a blog where they discuss HRV research and maybe they have an endurance athlete that posts a training log. I try and post some data and some new research here and there. So on any of those social media sources like Facebook or Twitter you could generally find some of these individuals.

[Damien Blenkinsopp]: Great, there are a lot of good references there. So of course there is your blog, which is HRVtraining.com.

[Andrew Flatt]: Yeah, I try and update it every once in a while. Things get busy so I am not as religious with it as I used to be. But the whole purpose of that was to just share data and there wasn’t much talked about it and I wanted there to be.

So that is kind of where it has started and now it has evolved to I will discuss some of our new research projects and post some new research. But it kind of was started with just posting data and then trying to analyze it and leaving it open for discussion.

So if you are interested in looking at some previous trends of my HRV or HRVs of athletes, where we discuss and analyze the data or try to come up with a meaningful explanation or some research review and you can check out the sites. I should warn you that a lot of the older posts, I kind of reread some of them recently, and they make me cringe.

[Damien Blenkinsopp]: Isn’t that always the way?

[Andrew Flatt]: Take it with a grain of salt when you read the older posts. I have learned a lot since I started and I have learned a tremendous amount. So just be aware that some of the other posts may not be a current reflection of my thought process these days.

[Damien Blenkinsopp]: Of course. Coming back to more of a general view in terms of you personally, what would be your top recommendation to someone trying to make better decisions about their body’s health or performance with data?

[Andrew Flatt]: You need to select what monitoring variables you are going to monitor and you need to be consistent with them. And you need to do a lot of trial and error. You need to almost separate yourself from the data, collect the data, analyze it later with your training lots, and see what it is telling you. If a training variable isn’t meaningful, if it is not – if you can’t figure out why you are measuring it or what it is telling you, then you probably don’t need to do it.

You want something – so, for example, with me and the resistance training I am continually experimenting with HRV. There is just not a lot of data in resistance training and how you may be able to use HRV as a tool to guide your training. So I am consistently just experimenting with it.

But it is pretty clear in the research that perceived levels of training load, RPE values, perceived levels of stress, fatigue, muscle soreness – those things are worth tracking because they do correlate with other markers of fatigue and stress. They are just noninvasive. They are easy to monitor and you go with it.

I can’t tell you not to monitor certain things because it is fun. It is fun to collect data, it is fun to experiment. But generally if you are just in it to try and improve performance, you want to pick the variables that are the most meaningful to you, that are the most supported, and you need to be consistent with it.

[Damien Blenkinsopp]: What other data metrics, biometrics, do you track for your body on a routine basis besides HRV?

[Andrew Flatt]: Well I do, again, the perceived levels of fatigue, muscle soreness, and all that through the app. I will do training load and every now and then I will calculate my tonnage, where I will multiply the weight I have used by the amount of sets and reps and so forth and see how that relates to my session rating of perceived exertion.

If RPE better relates to HRV or if the tonnage value does – I don’t do that all the time. It is time-consuming to do those calculations. But regularly I do my RPE for my workout. I will do my perceived levels of fatigue and muscle soreness and so forth. And generally there is a comment section so I will usually make a note or two of something that happened the previous day.

If I was out and had a few drinks with some friends I will make a note that I had a few drinks. If I am traveling, when my training structure changes, things like that – I will make note of it. And I do keep a training log where I write down all my workouts and so forth. So there are plenty others that you can do.

[Damien Blenkinsopp]: So it sounds like you have a little diary related to stressors and health in general.

[Andrew Flatt]: Yeah, and again that is all stored right on the smartphone app that I use. The training log in my gym bag is just a little notebook where I log my workouts. I was going through a phase where I was going through a reaction time test and a tap test, again, with two different smartphone applications. Honestly, I was doing it at a time where I was less familiar with certain statistical analyses and I probably really didn’t know how to analyze the data very well, but it is definitely something I have been interested in.

There is some data to support that psychomotor speed assessed through a reaction time test can be related to fatigue and overtraining. So there is a smartphone app. I believe it is free. And essentially the screen will prompt you to react to a light changing on the app. So as soon as the light turns green, you tap it, and then there is an unknown time interval where it will then prompt you to tap it again over a series of five taps. And then it will give you kind of the mean value of your reaction time.

And I think the data is pretty cool, that I have read, and that supports it. I haven’t really seen any kind of longitudinal data where it has been done every day with athletes, so that is actually something I would actually like to include in a future study along with HRV and some other measures, this reaction time.

[Damien Blenkinsopp]: Yeah, great. There are a few of those apps and I know that some of them are free because I downloaded and played around with them myself. But like you I haven’t really gotten into it. I played around with it once or twice. So thanks for all this stuff, Andrew. This is very detailed and we have really done the topic of HRV justice, really tackling it from every area. So thank you very much for your detailed explanations on everything.

[Andrew Flatt]: Oh, it is my pleasure.

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