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.

Leave a Reply

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.

Leave a Reply