Barbell Shrugged - Four Levers of Physiological Flexibility w/ Dr. Michael T. Nelson, Anders Varner, Doug Larson, and Travis Mash #816

Episode Date: September 24, 2025

Dr. Mike T. Nelson has spent 18 years of his life learning how the human body works, specifically focusing on how to properly condition it to burn fat and become stronger, more flexible, and healthier. He’s has a PhD in Exercise Physiology, a BA in Natural Science, and an MS in Biomechanics. He’s an adjunct professor and a member of the American College of Sports Medicine. Dr. Nelson has been called in to share his techniques with top government agencies. The techniques he’s developed, and the results he gets for his clients have been featured in international magazines, in scientific publications, and on websites across the globe. Work With Us: Arétē by RAPID Health Optimization Links: Dr. Nelson on Instagram Anders Varner on Instagram Doug Larson on Instagram Coach Travis Mash on Instagram

Shruck family this week on Barbell Farr, Dr. Michael T. Nelson, back in the house. The man, the myth. Love having this guy. I think Dr. Michael T. Nelson's been on a show like 37 times in the last eight years. Probably not that many, probably not even close to that many. But man, I feel like every day I'm waking up getting my brain filled up with knowledge from Dr. Michael T. Today we're talking about physiological flexibility in the four pillars that he is going to lay out on how you can build a more resilient and adaptable physiology. As always, friends, make sure you get over to rapidhealthreport.com.

That is where Dan Garner, Dr. Andy Galpin, are doing a free lab, lifestyle, and performance analysis. And you can access that at rapid health report.com. Friends, let's get into the show. Welcome to Marvell Shrug. I'm Andrew Farner, Doug Larson. Dr. Michael T. Nelson, my man. Dude, today, you're like the flexibility God.

You're the metabolic flexibility. Yeah. Did the cardio for meathead flexibility, like the breathing flexibility. But today we're going to talk about physiological flexibility. That sounds interesting. What I was about to say and then awkwardly stop right before the show is I actually, I don't think I've taken in a social media post about fitness or health in like three years without straining an eyeball when I roll my eyes so hard at whoever is saying it, even if they're like the smartest person in the world. Because all of this stuff is so specific on where are you supposed to? to do specific things at the right time and the right amount, and you just can't do that

with a broad general social media post, which is where maybe my frustration with the internet comes in. But today we're going to dive into actually making educated decisions for yourself, but first we have to get physiological flexibility. That sounds complicated. What does all that mean? Yeah. So I started with metabolic flexibility, which we've talked about before. How well does your body use carbohydrates? How well does you use fat? How well does it switch back and forth? So I've done a lot of work in that area, and that was the subtopics of my PhD.

And as I was doing that work for a while, I was like, okay, that's kind of cool related to metabolism. But what if we take that sort of flexibility framework and we extend it out to you as an individual person? Like how would we kind of frame different things? And so the framework I gave myself was, let's assume you're getting like a B in the basics. Like, so sleep, exercise, and nutrition. Like, you're already at a B. Like, how would you know what are the next things you should look at? And how would that compare to your physiology?

So I started thinking about, okay, so if you want better performance, I think you should teach your body to survive better. So what will be the next level of things that your body has to 100% do to ensure, survival. And number one is going to be temperature. People are homeotherms. Like you have to regulate body temp to a high degree. However, you can go into a hot environment. You can go into a sauna. You can go into a cold plunge. You can put yourself in these other extremes for a period of time, but your body is then going to still try to regulate body temperature within just a couple degrees or you're in a world of hurt. The second area would be pH. Same thing. You can do some horrible you know, wingate some high lactate type stuff and try to change your pH, but again, your

body is going to still try to hold that very tight. Third would be expanded fuels, would be lactate and ketones, and four would be just breathwork. So how do you regulate oxygen? How do you regulate CO2? Again, there's very, very tight parameters of which your body can operate, but yet due to adaptation and due to changes and training and acclamation and other things, you can expand the range of which you can operate in. So we're not necessarily trying to change the core value. We're trying to give you this more expanded, what I call like a human dynamic range. So you could go from a very hot environment to a very cold environment. And yet if we look at markers of stress over time, it wouldn't be that crazy. And so I think the physiologic flexibility is that next level.

So the four areas would be temperature, pH, expanded fuels, and then just breathing. And then if you get really good at expanding the capacity within each one of those areas, I think that'll increase your body's ability to recover and just make you more anti-fragile and generally just a lot harder to kill while also increasing your overall performance. So I feel like temperature is probably the easiest one here to dive in on. Yeah. You're essentially saying that you just put yourself at the extremes regularly and then your body adapts to those extremes. And then whenever you end up in a hot environment or a cold environment in this example, your body doesn't produce stress hormones or inflammatory markers, etc.

Because it's just used to being at the extremes. Yeah. And we know, for example, like there's a ton of published data on heat acclamation. So athletes, if you drop them into a super hot environment, we know their performance without any acclamation generally is going to be a lot. a lot worse. They're just not very good at adapting to the heat. I remember this every time I go down to Dr. Benhouse's place in Costa Rica in March and just, oh, like the first time I would just horrible, coming from Minnesota in the winter, had not done any sauna, had not done anything. It took almost a week to feel like I could operate again and exercise. But we know that with adaptation,

just like lifting weights, your body will get better at those things. So we have, let's say, an athlete who is going to compete in a very warm and hot environment, ideally two to four weeks out or maybe even a little bit longer, we're going to slowly expose their physiology to heat and watch their performance instead of just trying to drop them in and go, oh, you know, I hope you do well. So we can train those systems just like you can train your right biceb, you can train your body to use carbs, you can train it to use fat.

We can train it to get better at different environmental stimulation. And the example I like to use with this is sort of the barbell model. And in a perfect world, I have people usually start with either hot or cold adaptation, and it just makes it easier to figure out how far we can push it. So let's say someone has access to a sauna to make it easy. They can say, yeah, sauna's at at 185. You'll try just 10 minutes. And let's look at your HRV.

How do you feel the next day? Okay, that was pretty good. Maybe we'll just slowly increase the total time. and the total exposure. And we can monitor the stress of the body by looking at heart rate variability the next day is our marker. And over time, just like exercise,

you're going to increase, you can play with temperature and you can play with volume, right? So we're going to increase kind of the dose of which we're doing to your system. So for most people, that right end of the barbell model, that would be heat.

So I would ramp them up over time, you know, probably four to five, maybe six days a week, do some heat exposure. And then once we get close to what we think is, our more maximal adaptation, then I would actually start playing with cold adaptation. Just like if you're really trying to get the farthest you can on speed and power,

you're probably not going to try to train to run a marathon at the same time. You're going to pick the thing that you want, the stimulus you want your body to be exposed to to, to adapt to you better. So we'll put kind of the heat adaptation on hold, maybe just a couple saunas during the week, but we're not really going to try to progress that model any further. and then we're going to play with cold exposure. Same thing. Maybe you start at 50 degrees for just one or two minutes.

And then we're going to expand that out over time, doing more time, and then colder temperatures. And then once you get that pretty good, so now we've got both ends of our barbell that are pretty decent. Then it would actually play with like a contrast therapy, going from hot to cold and then back and forth. A lot of people want to start with just contrast therapy first. and I don't know it just seems like you can do okay and sometimes you get lucky and you get to the right protocol

and it's fine but if it's not it's really hard to troubleshoot were you in the sauna too long was a sauna too hot are you not adapted to hot are you not used to the transition or you're not used to the cold

like there's so many variables going on it makes it really hard to troubleshoot what's going on yeah I the going to a hot yoga class was like one of the first fastest ways to see that adaptation, and I always enjoy watching it happen.

Yeah. You go in on day one, there's some like 90-year-old lady just kicking your butt in there. You're like, gone, you've already gone through like a gallon of water. You're just sweating there, feeling bad for yourself. You can't even like get through half the class. And then two weeks later, you're doing pretty good. You like get it. Your body totally can handle what's going on.

You also lose it pretty quickly. Um, that if, if people don't have access to a sauna, pretty much everybody can find one of those, uh, hot yoga places to go in and feel the pain on day one. And then it's really like six sessions or so, five to six sessions and you can kind of like feel all of a sudden that your body just quickly adapts to, to the heat and it doesn't bother you as much. Yeah. And it, and it, and it sounds crazy to say, but if you live in warmer environments, shocker, you could exercise outside, you know, Like, I'm famous for taking my roller out of the garage and sticking it in the middle of the road or at the end of your driveway or something like that because I think we're so used to wandering from one air-condition thing to an air-conditioned gym to the next thing. Like, I actually like that my garage doesn't have much heat and doesn't have any cooling in it. I think being exposed to the elements and the temperature, I get a lot of that stuff sort of baked in with just the seasonality in Minnesota, too. So I think people sometimes forget that if you live in a warm environment or a cooler environment,

like you can just use the environment and it's completely free too. Dr. Andy Galpin here. As a listener of the show, you've probably heard us talking about the Artae program, which we're all incredibly proud of. It's a culmination of everything Dan Garland and I have learned over more than two decades of working with some of the world's most elite performers, award-winning athletes, billionaires, musicians, executives, and frankly, anyone who just wanted to be at their absolute best. Artae is not a normal coaching program.

It's not just macros and a workout plan. It's not physique transformation and pre-imposed pictures. Arte is something completely different. Aratee is incredibly comprehensive and designed to uncover your unique molecular signature, find your performance anchors, and solve them permanently. You'll be working with not one person, but rather a full team of elite professionals, each with their own special expertise, to maximize precision, accuracy, and effective. of your analysis and optimization plan.

Artae isn't about treating symptoms or quick fixes. It's about unlocking your full potential and looking, feeling, and performing at your absolute best, physically and mentally, when the stakes are the highest. To learn more, visit Arteelab.com. That's A-R-E-E-E-Lab.com. Now, back to the show. If you live in a warm environment or a cooler environment, like, you can just use the environment, and it's completely free, too.

I live in a really hot place in the summer and humid. And I love when it's like 105 and so humid. And one other beautiful thing, this may not be real. So not everybody, you don't have to trust me. But if you start preparing yourself for the summer in like February and you get outside and you take your shirt off, maybe not where you live. Don't do that. It's really cold in February.

But in North Carolina, like late February, you can kind of start like, it might not be warm, but you can start being outside. You can start interacting with the environment a little bit more. And then all of a sudden, when summer gets there, you don't need sunscreen. All of a sudden, because you've been increasing the sun exposure on a daily basis, even if it's just like 20 minutes at a time or 20 minutes a day, by the time summer gets there, you're kind of like adapted to it. Like, you're still going to sweat. It's still hot. You're not going to escape it, but it's not like you just walked out of an air conditioner on June 1st and melted. Like, you just slowly, you know, three degrees a day all of a sudden.

And June shows up and you feel amazing. And this you, in my opinion, I start to look forward to like the, your body like warming up. You know what it feels like in Minnesota when your body like thaws out and all of a sudden you can enjoy your day again. but it is those small like the the idea of like progressive overload heat and cold etc I think people just it's hard to think about that when you're trapped in your house for you know three day or three months or whatever it is in the winter and then but you can go and do that with sauna somewhere or you can get it you know, hot yoga, um, all those, all those things just like start to really just allow your

body to slowly progress into it. Yeah, for years in the past, I could never figure out like in spring in Minnesota. I would always have this like, you know, two, three, four week period of just this massive drop off of my performance. And once I started looking at the physiologic flexibility stuff, um, I went back and looked at the temperatures and realized, oh, the times I would have this huge performance drop is where it would stay relatively cool. And then we would get like these, you know, two or three weeks spike and temperature of warm and humid weather. And it would always take me at least two weeks to get back to kind of baseline again. And so once I realized that, I was like, oh, so now if I build up a little bit more heat adaptation, I'll try to do sauna just once

or twice a week in the winter. And then when that period comes around again in spring, it's really not too bad. I feel like I can hold a lot of those heat adaptations with, again, like kind of minimal exposure, just like strength and just like muscle mass. Once you've built it, it doesn't take nearly as much to maintain it. Like to break new ground and to make new progress, that can be a little bit more arduous. But to try to hold some of those adaptations doesn't really take very much compared to what it takes to build them. Are there physiological needs specifically for heat and cold. And the reason I asked that is when it was like 55 degrees when I lived in San Diego, I would be frozen. Yeah. It would be like February. And if it was February in Minnesota and

it was 55, everybody would be out tanning. They'd be like, oh yeah, it's a shirt off weather, man. When you live in San Diego, I had a client in Alaska that used to tell me it was 35 degrees. All the guys would go outside, take their shirts off to try to get the sun on their body. I'd like, I'd crazy because they've been in a negative whatever for four or five months and the sun hasn't come out and then all of a sudden there it is it just happens to be you know 40 degrees and they think it's summer um but i the opposite of that is when you live in san diego and it's beautiful all the time in february when it gets slightly below 60 degrees you're in like a parka but i started to think that there's some physiological need like your body has to be cold and

order to be healthy because there's no reason for it to be cold when it's 60 degrees outside. Yeah, there hasn't been, as far as I could find on research, any, at least it's been published in humans, negative effects from living in a very tempered environment all the time. But you could argue that that just study really hasn't been done and done well. My argument is that we're kind of running that experiment right now because like you said, most people are just so used to the same temperature that it's I don't think it's going to end well so the example I use is so my grandma lived to be past a hundred and when we visit her in the nursing home at the end and anyone's ever been a nursing home there's like 78 degrees in there you're just like

profusely just absolutely sweating and she's like I need a blanket I'm cold right and you realize that as people got older they lost that ability to kind of thermal regulate it was very difficult for them um to do that so i do think it is a negative to what degree not really sure but again we can point to there's tons of benefits that's been published with sauna which is just artificial heat some super interesting benefits has been published with cold so we do know that on those extreme ends we do see benefits to our physiology as long as we don't go too far in any one direction so i do think there is a detriment i think you could probably make an argument of anything static is going to at some point turn into a like a degradation in

adaptability that was like a lot of big words in a row but you're not sounds impressive you're not improving which means you're going backwards at some point if things if you're not adapting to an environment so like at 72 degrees every single day your body just doesn't have to turn on the mechanisms to keep you warm or keep you cold or cool you down and that's that's going to at some point just again getting to what you're talking about like your body does not have the flexibility so when there is a need it doesn't know how to turn that switch on yeah I think of it as your body is constantly adapting to everything and it's very interesting we don't really lose that ability to adapt but the better question then like you were saying is what are you adapting to

I think most people are probably adapted to too much of a thermal neutral environment. Now, again, I have heat in Minnesota. I have air conditioning. I am very grateful I have heat and have air conditioning. I don't think we should go all super paleo and sleep in a cave with stone pillows again. But because of modern conveniences, which I do enjoy and I think are beneficial, we're going to lose more of those adaptations. And it doesn't seem like you need a ton of time to be invested to improve them.

and to see some of the benefits. Like you don't need to live in a sauna. You don't need to live in a cold plunge. But even just a few minutes, sprinkled over the course of the week, appears to have a fair amount of benefits from that investment of time. Yeah. And who are those benefits primarily for?

Like if someone is an elite athlete, they're dialed in every other way, then they should actually spend some time worrying about the temperature of the competition setting they're going to be in and they're going to use temperature leading up to their event to adapt to it. et cetera, et cetera, but if you're not competing in a hot environment or a particularly cold environment, granted, there's other benefits to ice baths and saunas and et cetera, but who really needs to worry about this and how much of a performance improvement can they really expect?

Yeah, it's a good question. So obviously the first case would be, as you mentioned, simulation. If you're going to compete in a hot environment or you compete in a cold environment, make sure you're adapted to that environment you're going to compete in. So that's kind of a no-brainer. most athletes are pretty good at that. Outside of that, like I said, it depends upon, you know, obviously exercise, nutrition, and sleep are going to be your big pillars. Make sure you're doing well in those. After that, if we look at the literature, it's kind of across the board.

There's some literature showing that acute exposure to warm environments will increase endurance output, and that's primarily from an increase in plasma volume. you just have a little bit more blood and substances to push around to the rest of the body. There's some data on sauna promoting recovery. And now I think of recovery is just simply, can you get back to baseline faster by doing something versus not doing it? So in some cases, in athletes I've worked with, just adding a simple sauna and some simple breathing after training, they may have been able to train four hard sessions. You know, now maybe they can get in five.

So they can push the stimulation side of the equation a little bit harder to try to get those adaptations that they would want. The research on cold is a lot more mixed. There is some data showing recovery of maximum power output, vertical jump. There's some data showing that it didn't recover. Obviously, we can talk about some of the data showing the potential loss of hypertrophy response, but there's some other data showing no change in that whatsoever. So I would say on the cold side, it's definitely more mixed. And how I think about it is, if you have an in-season athlete,

I don't care quite as much about anything affecting the chronic adaptations. I'm more concerned that that athlete hops to perform again, maybe the next day or the next week or the following Sunday. So I'm going to prioritize a U-Stress model of we're going to do whatever we can so that you're ready to go, money you need to go. And, yeah, we'll kind of worry about the chronic adaptations, but that's not really our big thing right now. However, in the off-season, if we've got, you know, four months, three months, whatever,

now we are super worried about those chronic adaptations. And we have the luxury of time of setting up to see maybe acute performance degregations to see more positives in the future. So that's how I would think about it in terms of hot versus cold, in season, not a season. And the last part, too, is this personal preference of the athlete. You know, some athletes will report that they absolutely love doing cold water immersion. and if I don't see any negative effects on any recovery, great, you know, go ahead and do that. Some athletes really like doing sauna better, you know, so at the end of the day, I'm going to

prioritize it, you know, towards what their preferences are also. And I think there's maybe been a little bit too much emphasis on the physiologic response and not enough emphasis on the individual, even just purely psychological response, you know, of athletes and just getting them used to a routine and a lot of what they even associated with it you know maybe sauna it just turns out in certain athletes is an associative thing that they think is going to benefit them and then you know it does great i might i might do that then uh with them so a lot of it i think depends upon the individual also so if you love ice baths then great but if you don't love ice baths then now they're stressful potentially in a in a negative

way is that kind of what you said Yeah, potentially you have like what's called placebo versus nocebo effect, right? Placebo is, oh, I unconsciously think that this thing is going to be beneficial. And even if you got the sugar pill, you see an increase. Nocebo is, I think this is crap. This isn't going to do anything for me. And you may see more of a negative effect. Now, we don't have really good controls on ice bath studies with placebo versus nocebo.

They've tried to do it and compare it to, you know, sham interventions or sitting quietly in another room. or different temp of water. Some of the better studies will do one leg compared to the other leg. So you're trying to control for each individual. But it's also unrealistic, too. Like, if you've been dunked in cold water, you know you've been dunked in cold water.

Like, no one's going to put you in warmer water and say, hey, no, this is the same tip water, right? You are going to feel a difference. So there's only so much you can do to get around that. What I would love to see, I don't think this has been done yet, is a study where you have a group of people, who love ice bass and you've got another group of people who hate ice bass and then you get both

of them the exact same intervention like do those groups see a difference i'd be super interested to see with that because that would be kind of one way you could get at what are kind of the psychological effects and the other part too is that even on an elite level athlete not all of them will do everything that you tell them to do right there's still humans they still have things they like things they don't So how much of your sort of, I'd say, personal capital and pull with them, are you going to burn on having them do an ice bath versus a training session versus doing something else? You know, there's probably maybe some other, you know, bigger leverage things you could move first. Again, not saying that those other things don't have benefit. It's just you kind of have to sort of pick your battles too at the end of the day.

Yeah. So the physiological flexibility piece for temperature is pretty straightforward. if you want to make yourself extra hot yet we have easy ways to do it if you want to make yourself really cold we have easy ways to do it uh you you mentioned pH I feel like making yourself very acidic you mentioned Wingate which is kind of like a salt bike sprints just you're just you're going as hard as you can you're getting a lot of quote unquote muscular burn that's that's acidity you're producing hydrogen ions and as a result your your pH in that case is going to go down which means your body is getting more acidic your your blood as an example keeps

you in a very tight range. How do you make your body more basic? I know some people will ingest like baking soda and that type of thing. But what are all the methods for both of these for both ends of the extreme as far as pH goes? Yeah, so for pH, you're correct. On the aesthetic side, it's any amount of high intensity output

in the lab we classically call these windgates where you're going maximum output for 20, 30 seconds. There's even 60-second protocols for that. So you're doing a high-output glycolytic work. You're running carbohydrate metabolism really hard. You're producing lactate plus hydrogen ions. And it's the hydrogen ions that are literally acid. Like you're literally dumping acid into the muscle.

So the counteracting system of that or the buffering system, how would you make things more basic? The two main are you have your kind of intramuscular buffering, which is intramuscular carnacine. So carnacine can be increased by consuming the supplement beta alenine. So beta alenine combines an el-histinine to form intramuscular carnacine, and that can help buffer some of those hydrogen ions. You can use sodium bicarbonate, which is more of a blood buffer.

That can buffer some of the hydrogen ions as they're sort of leaking out and getting moved around somewhere else. The downside with sodium bicarbonate is it, even in the literature, the variability of how people respond. to it is much wider than beta alenine. Meaning some people respond really well to it. Some people don't. And the dosing is a little bit harder to titrate because if you go too high on it, which

I may have tested this on myself and athletes maybe about 10 years ago, it definitely feels like you don't want to stray too far from the toilet. And you get massive GI upset. I've heard horror stories about wrestlers doing this. Oh, yeah. And then they're out on the mats and they just run. Yeah. So about probably 11 years ago, I was reading all the research on this and I tried it on myself and I kind of kind of figured out what the dosing was. And I was working with a Danish sprint kayaker at the time. And so we had played around with it. We slowly got him up to, you know, pretty good dosage. And we saw some improvements in his time. So this was a practice one run. We said, okay, I had in my head what I thought was a maximal dosage. Had him try it emails me back. He's like, like what what happened like he was just way slower he's like you know i felt pretty good

but i still felt like i was going to shit myself the whole race and i had a hard time focusing he didn't but he was so worried about because he had the GI that kind of you know rumbling and those kind of effects that completely destroyed his performance so we were like oh i just don't let's just not forget about it at all at you know not worry about it's like oh thank god you know Because even I would just mention it at a small dose. And he's like, no, no, this is, I don't want to do this. He's got, like, super worried about it. But the sodium bicarb is going to have that more acute response.

Like, beta aline is something that's a little more chronic. Like, you're going to, you're going to titrate up to a saturation point over the course of many weeks. But you're not going to get, like, this spike in, in, in, the last, what's right, term here? Offering capacity. Yeah, like a spike like you would get with these sort of bicarbonate, like you would, if you're getting in a sauna or an ice bath, like you're getting extreme temperatures for an acute period of time and then you go back to normal.

With beta aline, you're not going to get it in the same way. So does it work the same given that it's not such an acute response? Yeah, you're correct. So the time per sonatom is completely different. Zodium bicarbon is much more of most like an acute effect for performance. Just like caffeine is more of an acute effect. But other things that are stored in the muscle, like creatine is a great example. And then when beta alenine gets converted off to carnissine.

So the loading period for beta alenine is probably going to be six grams per day for about 30 days. If you look in the literature, it's about 180 grams of beta aline you need to hit to probably get close to saturation. The interesting part on that is it doesn't appear to be rate limited, meaning in theory, I don't recommend people do this. You could take a whole bunch of beta aline at once and maybe do some type of loading protocol to get. there sooner. The downside is you get the very kind of itchy, like you want to scratch your skin off type effect. There's no negatives associated with that other than some people it feels horrible. Like in myself, like it just, oh, it just feels bad. So there's a little bit of that issue to work around. But then you're loaded for probably a 30-day period and then you're going

to see a drop off there. So the other thing related to FISFlex that I look at in athletes then is do we see a higher output in their performance then? Because, again, the data on beta aline is definitely variable. Most of the meta analyses would say 120 seconds to 240 seconds. If you're going all out for that time period, that's probably the better beta aline performance. But, you know, we have seen some stuff, you know, much lower than that in terms of timeframes. So I want to see, do they have an actual higher output?

If they have an higher output, we could theorize that they're producing more hydrogen ions, but they're better able to buffer them now and we're seeing a little bit higher level of performance from it. So different mechanisms, but those are some ways to play with that. Last part two on the basic side, if you do some type of Wim Hof breathing, especially the superventilation method, if you are inhaling and exhaling really fast,

in essence, you are off-gassing more CO2. And if you off-gas more CO2, it is true that you do make the blood a little bit more basic for a period of time. So if you want to go to the other extreme end with that, that would be the other thing you could play with. Okay, so back to the original, the original term of physiological flexibility. So there's many reasons that we could do all these things. But with the term physiological flexibility, you're intentionally trying to hit the extremes of acidity and hit the extremes of lack of acidity, we'll say.

so that eventually when you do hit the extremes, you're more prepared to perform well even while you're at those extremes. Is that what we're working on for this conversation? Yep, so you can imagine like a certain capacity. So you have a certain capacity. And over time, I'm trying to increase that capacity or what I call a human dynamic range.

Like if I do really absolutely brutal exercise, how many hydrogen ions, like how far could I really push my pH? We don't have really good markers for pH. So I'm going to use performance as kind of my output for that. And if I'm doing something in that really high kind of lactate area and I can see higher levels of performance over time, I'm probably, we can infer a little bit better at buffering some of those hydrogen ions. Again, there's a whole bunch of other things that are going on. Same thing on the other end. So you're trying to, the phrase I like is the extremes kind of inform the means. If I can move that high point

and that low point farther apart, I have a better dynamic range. And so, regulating the thing in the middle is just going to become a lot easier. And then also, like you said, if I'm exposed to those types of conditions, I'm already more adapted to that. So it's less stress on the system overall. And the other part that there isn't much literature on this, something called a cross adaptation. So I think just like in lifting,

so if you said, hey, you know, how do I increase my deadlift? Well, you know, you should probably go deadlift, right? I mean, the most specific thing is a place you would start. But I'm probably not going to be able to deadlift every single day. So what might be another exercise to transfer to my deadlift? Maybe I'll say kettlebell swings. My kettlebell swing doesn't look like a deadlift, but maybe it does transfer to increase my deadlift over time.

And so in physiology, there's things called cross adaptation. And one of the coolest ones they did was they had a group where they exposed them to hypoxia. So a low oxygen condition, which is very threatening for humans for obvious reasons. And what they did is they exposed one. half of the group to cold water immersion and then did the hypoxia the other group they did not and the group they exposed to the cold water immersion right before the hypoxic event they reported that it did not feel as stressful I don't remember if they did a breath holder did it some of their marker but they showed a benefit to hypoxic environment and on face value you look at that and you're like well what the hell

like one's regulating oxygen and one's regulating temperature these these should be like two completely different systems. And there's some mechanisms in the background that actually seem to cross over. So I think in the future we'll find that some of these expansions in different areas are probably benefiting other areas. We just don't have a lot of research in that area yet. And it just hasn't really been looked at a whole lot. So I do think there's probably more transfer between each of those four domains and what we probably realize right now. Gosh, so you got temperature, pH, where were the other categories you mentioned? So number three would be expanded fuels.

So on the right hand of the spectrum, we've got carbohydrate use. So sort of the cousin of high carbohydrate use is going to be lactate. And then on the other end, we've got fat. So the cousin of high fat use is going to be ketones. And I think you can make an argument. There's some very interesting data. You know, Georgia Brooks's labs, I've been looking at this for a long time. The people that do high-intensity exercise, we do see some cognitive benefits.

And one of the theories there is that that's from the, the production of lactate, lactate goes to the brain and can be used by different, you know, circuits. It may help with cognitive function. There's some interesting data now that you can get exogenous ketones. So you can take ketones as a supplement. Usually it's beta-hydroxybutrate bonded to some type of other precursor. It's what's classically called a ketone. And that those can then increase your body's BHB levels directly by just a supplement. And the benefit is it allows you to do different testing. So like Brandon Egan's done some very interesting testing on having higher levels of ketones. Do you cognitively perform a little bit better under high stress conditions?

I would say most of that data says probably yes. It's not definitely a, you know, 100%, but there's some interesting cases where having higher lactate or having higher ketones might be beneficial. The other case where ketones would also be concussion. Can I jump in on that real quick? So this is a total anecdote from my life. But I feel like with regard to ketones and the cognitive benefits of them, I feel like it's very often, in my experience, older people, guests on the show, et cetera, who are like in their 50s and 60s that are like, I tried ketones. And man, I was just so my, I can think so clearly for the first time. And I wonder if there's any data or research that's been done to show how ketones affect cognition and, what have you during each decade of life like if if again this is total speculation

I have no data on anything about to say but if like if Alzheimer's is considered to be like type three diabetes and and the ability to process carbohydrates within the brain is is altered for some reason and by and large older people are the ones that have Alzheimer's of course like there's got to be some progression from from childhood to old age where if you're over time not processing for large groups of people on average, not processed in carbohydrates, as well as you could. And that decreases every decade of life. Then ketones may potentially be more and more effective as people are losing that ability as they get older and older and older. Do you know if there's anything out there that is similar to what I'm saying? Yeah. So I would agree with that.

And that's been kind of my pet hypothesis for many years too, is that the people who tend to, and this is healthy population, this is not pathologies or anything, respond better to ketones I've wondered about in that cognitive side if their brain just isn't really quite as good at using glucose. So now you give it another substrate that it can use a little bit better. They're like, oh my gosh, I feel so much better. And it may explain why people do shift work, people under high stress, exercise is a high stressor. The ketones at baseline in some of the studies don't show a huge benefit to cognitive effect, although I would say there's a huge amount of variability to that. But when we add a significant stressor, now we start to see that, oh, wow, there are more

benefits that emerge. So I would agree with you that I think if you are a hyper responder to ketones at baseline, I often wonder, is your brain just not quite as good at using glucose? Is there something else going on there? And the hard part is the studies to look at that are really difficult. If it's a muscle, we can do a classic of what's called a clamp study or insulin clamp. We can just go in and we can put a crap ton of glucose in one side and a crap ton of insulin on the other side. We can kind of measure what's going on with physiology. We can't really do that across the brain without really bad stuff happening. We can't get direct biopsies from the brain. So we have to use MRS. We have to use these other technologies

to try to figure it out. So I would agree with you. I have been able to play with a lot of ketone I do some work for tecton ketones, this is full disclosure. And it feels like to me that if I'm well rested, my stress is good, everything at baseline is pretty good, I don't, even at high doses, like I don't notice much of an effect. Me as an N-O-1. However, if my stress is high, my sleep is off, things like that, I tend to notice a much greater effect or even just towards the end of the day versus the beginning of the day. So I do think there are some dynamics changing there.

And last part is we do know from concussion or TBI traumatic brain injury that if you take a big walk to the head we have pretty good data now in humans and animal models showing that the glucose of tablism gets completely screwed up

and your brain starts producing a lot of inflammation. You may even have the brain blood barrier open up so now you've got other chemicals that are getting into the brain and there's some preliminary work showing that ketones appear to be

quite beneficial for that. They do cross the blood brain barrier. They do appear to be anti-inflammatory, and they're providing a direct fuel source that your brain can still use. It can still pull lactate and it can still pull ketones quite well. So now you're trying to resolve some of this energy crisis that the brain has. So I did the whole program for the Nicarag Institute on the use of ketones for potential

TBI and concussion applications. When you first said fuel, I actually was not expecting you to be talking about ketones at all, like a supplementing fat sources. Oh, sure. And much more I was expecting you to come to, can we increase our performance being underfed, how much does it affect your metabolism, being overfed,

and more kind of expanding the caloric amount. Is there anything to that? Is that also play into this, where you're just trying to widen the gap of calories where your body's kind of not, maybe call it not influenced on the performance side by how many calories you're eating or what you kind of already got into like the macro side of it, but even larger on the calorie side. Is that a piece of this?

I definitely think it's related. How I think about that is two things. One, if I have a competitive athlete, I want to make sure their metabolic flexibility as high as possible. and then I'm going to do simulation things to see how detrimental removing of certain, like if they get too attached to their pre-workout meal, can I take it away and can they still perform? You know, if they're an endurance racer,

if they miss a way station, can they still perform? Like, so military people, can you stick them out in the middle of the woods for 48 hours? Can they hit all their targets, right? Can they do everything they need to do under these more extreme conditions? So I do think that there's that one aspect. of performance. And then also related, in a perfect world, I'll move people up to what I call a higher flux rate. You know, John Breyerty wrote an article decades ago now called G-flux. And I was the first article I read and I was like, oh, fascinating. Because let's say Bob comes in

and Bob's like weight neutral on 2,000 calories a day. Yeah, you know, if he wants to lose weight, we'd have to go to maybe 1,500 calories per day. Could he white knuckle his way through it? probably, but that's going to be a little bit harder. Now, let's say he's weight neutral on 3,500 calories per day. Well, 500 calorie deficit, he's only still, he's at 3,000 calories per day, right? That's going to be a lot easier in a world that's full of food to maintain. Now, the cost of that is most people have to increase the amount of energy, their expenditure, in order to be weight neutral at a higher calories. So I think if you're at a higher calories in, higher calories out. I do think it is easier to make changes. I do think you're a little bit more

flexible overall. The cost of that is you probably have to spend more time doing some type of movement, walking exercise, cardio, that type of thing. But I think all things being equal, there's some pretty interesting, a little preliminary data showing that higher flux rates are better. And the last thing, looking at the muscle itself, for years we had this thing called the Athletes Paradox, where they would take samples of muscle from people who weren't very And then we'd see all these fat droplets next to the muscle, like kind of like the marbling if you have like a fancy steak. That's actually intramuscular triglycerides you're looking at on the steak.

And they knew that this was related to insulin resistance and a whole bunch of negative outcomes. And then one day they started doing pictures of high level, I think it was endurance athletes. And they're like, oh crap, these athletes still have these high amount of intramuscular triglycerides next to the muscle. But when we do an insulin clamp study or we do something across the muscle, they're extremely insulin sensitive. Like, they don't have all these negative effects we thought were from these intramuscular triglycerides. And then further studies with tracers, they realized in the athletes, that triglyceride amount

on a static picture was the same, but there's a lot more going in and there's a lot more going out. So the flux rate through that was much higher. On people who are not athletes or sedentary, there wasn't really much flux rate going through it at all. So, again, you know, some data, at least on a cellular. level that I think having these higher flux rates are going to be beneficial.

Number four. Yeah. Number four is just regulation of oxygen and CO2 which I think people kind of take for granted and there's been a lot of people who've done a lot of great stuff, you know, talking about breathwork. But I think the

thing that's been missed is what are you trying to do and what are you trying to affect? So again, if I pick on Wimhoff breathing. So Wim Hof breathing or superventilation method or classically called Tuma breathing, you're inhaling and exhaling very, very fast. Now, it is true you can push your body to be temporarily a little bit more basic, which may have some benefits, but that's also a high stressor that you're putting on to your system. And if your job was, let's say, to try to downregulate after exercise before bed, I would not recommend doing Wimhoff breathing. And early on I had a couple,

I had one athlete in particular, came to me, we like could not figure out why her HRV was so bad, her performance was dropping, everything just wasn't going in the right direction. I finally asked her, is there anything else you're doing different? There has to be something going on. I looked at these numbers long enough,

like there's something going on. In my head, I'm starting to think, just you have some weird infection, you know, she's got something going on. And then she's like, oh, well, I started doing Wimhoff breathing with cold plunges. And I'm like, oh, Well, what was your cold plunge?

She's like, well, I heard it's supposed to be really cold. So I was doing 37 degrees for five minutes. And then I would do like eight rounds of Wimhoff breathing like after that. And I'm like, oh, how did you feel during the cold plunge? She's like, oh, miserable. I was like shaking and shivering. And I'm like, yeah, those two in and of themselves could definitely be enough stress to just, you know, put you over the edge. Of course, you know, cross-wood athletes.

So I love working with. She's like, oh, I was doing it every day, you know. So if you're going too far in any one direction, again, these are stressors. So you can cross that area where if you can't get back to baseline within a reasonable amount of time, now you are just adding more exogenous stress to the system. So again, I think with the CO2 and the O2 are, what type of breathwork are you doing? And what are you trying to affect? So one thing we've talked a lot about at Rapid, too, that I know Andy and Dan have talked a lot about is

if you have someone that has a very high respiratory rate overnight, you know, 16, 17 breast per minute, they're probably getting rid of too much CO2. And that is a baseline 24-7 stressor that's running all the time. Because as you increase respiratory rate, that is a signal to your body that there's more sympathetic stressors going on. Just like when you're doing a high-level exercise, you're going to have a much higher respiratory rate on purpose. So doing some type of hypoxic walk, some type of zone two where you're purposely doing a long exhale. You're trying to keep a little bit more of that CO2 in your body.

So those chemoreceptors and those things change in the brainstem to say, oh, okay, it is okay. We can operate at this level and we're going to be okay. So we're going to turn down respiratory rate over time. We don't need to constantly just off gas all this CO2 at the rate we were doing before. And then usually you see the HRV gets better, their performance gets better overall. yeah um one question kind of tying all of this together that that comes up is um i feel like and this is also why i love crossfit so much is like i'm like a b plus maybe even on a great week like

an a minus at all of these things um where it's like i i can i can go fast i can go slow i can sit in the cold i can do the heat like all of these things higher calories lower calories higher fat, lower fat, higher, like, I feel like the adaptation over multiple decades of being focused on training and doing different things, you start to get to a point where your body's just kind of adapted naturally over time to many different factors and you maintain muscle mass and performance and strength and, et cetera, sleep's good, et cetera. When I call you and I go, I want to run a six-minute mile, does the, does my business, body's ability to adapt to so many things actually slow down the progression because it is always

going to be chasing that like homeostasis of like Anders needs to be at these things no matter what the stimulus is. Does it slow it down where I need a longer timeline to hit goals or does that actually help me get to the goals faster? Yeah. My biased opinion and I can't point to a single research study on this is if you have Anders who's really physiologically flexible versus Anders who's not, I would rather train the Anders who's physiologically flexible because I can then point it more at a specific direction. And in my experience, I can push volume and intensity normally higher because you'll be able to get back to baseline faster. And the second part of that question then is this goes all the way back to coaching. Okay, you still have a

finite amount of resources that you're dealing with. So what is the goal and where do you want to spend those resources? So if everyone's pretty good at those four pillars, I just have them, you know, kind of just hang out on maintenance. Like there's no reason to really push it. But if I find, for example, someone is extremely intolerant of cold, I might think, okay, in the background, let's try to get a little bit more of that adaptation, but I'm still going to be careful not to overwhelm them. So if the goal is a six-minute mile, that's still the goal, not I don't want to be, you know, Wimhoff and, you know, break some world records in cold water immersion, right? So you still have to weigh everything with the goal of coaching, but I would still look at those things and I would still push some adaptation reserves towards that direction because I think long term there's going to be a beneficial payout for it.

Yeah. I would, and my personal experience, I would agree with all that. I like the idea of having kind of like all of the things dialed in and a way. that also matches a lifestyle where you can still not be overwhelmed by everything. But having a B-plus and many things, or most of the things, when someone says,

you want to go run a marathon, call it a half-marathon, it's a little more sustainable or attainable. You just go, yeah, I'll see it the star line tomorrow. And it's not a big deal. Or can I go do a year of mile training? or let's do some Olympic lifting. Like having the broad, uh, experiences allows you to go and do more things

without it completely destroying you and being, um, kind of like not in your wheelhouse. Um, but I've always wondered, is there like the other side of the pendulum where you go, yeah, because your body likes to be at a B plus, it's just going to try and stay at a B plus. So it's harder to get to like an A in many of these aspects just because that's kind of like where you've where you uh having a broad general health call it doesn't allow the extremes when it comes to specific goals yeah i mean again we pick on crossfit i think crosswood does a very good job of hitting most of the the basics but i think if you wanted to be an elite level power lifter or elite level Olympic athlete or endurance marathon i wouldn't have you do crossfit right i would

have you say, yes, I will take that athlete who has those baseline abilities already. Yeah, all day. Like I think they're probably going to be able to progress much faster. But then it comes back down to what is the specificity of the goal. So now I'm going to take that physiologic potential that I think CrossFit does a really good job of building. But now we're going to point it to something that's much more specific because we're going to need to get, especially someone who's been training for quite a while. We're just going to need to get more high quality work in that area. And the older you get and the more specific you get and you get to a higher level, I think what I've seen is that the rate limiter is how much high quality work can you do and

repeat it. The athlete who can do more work and keep it at a high quality and get more frequency is going to get to the result faster. I think that a lot of times just becomes your rate limiter. You know, if you could train with really high quality six days a week versus is three. I'll take six days a week all the time. And I don't think that's going to be a two-x return. I think you're definitely hitting the part of the curve where it's going to start to flatten out. But I do think you would be better overall for doing that. Where can the people find you, sir? Yeah, so the best place is the newsletter. Go to mike t-nelson.com. There'll be a little button for newsletter there. So I send stuff out on a daily basis for free. I'll send you a

free gift. I have some stuff on Instagram, Dr. Mike T. Nelson. And then the podcast is Flexdy podcast. There you go. Doug Larson. You bet. I'm on Instagram. Douglas C. Larson. Mr. Michael D. Nelson. Appreciate you coming on the show. Yeah, thank you guys. I appreciate it. I'm Andrews Varner. At Anders Varner. We are Barbell Strug at Barbell underscore shrug to make sure you get to Rapid Health Report.com. That's where Dan Garner, Dr. Andy Galpin, are doing a free lab, lifestyle, performance analysis, and you can access that at rapidhealthreport.com. Friends, we'll see you guys next week.