← The Neuro Experience
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- [00:00]
A
People on the Internet, which, it really bugs me when they say, oh, this, you know, lion's mane improves or helps with neurogenesis. I'm like, no, I don't think it does, but it does help with synaptogenesis, which is, you know, literally the connections. If that were true, I think we'd all be going out eating tons of mushrooms to just get bigger brains.
- [00:17]
B
Runners and cyclists, they have a high VO2 max. So therefore it's important for endurance exercise performance. But it reflects now kind of what we're realizing, why it might be so important for, for like, health and longevity. It reflects your body's integrative ability to.
- [00:32]
A
Produce, produce energy what VO2 max you need to have in order to just walk around the block or maybe just get up out of bed and just to maintain everyday function. Hi, everybody. Welcome back to the show. It's Louisa Nicola. I'm a neurophysiologist and human performance coach. I'm the founder of neuro athletics where our mission is to democratize brain health education so you can perform better, think faster and live longer. VO2max is arguably the single most important metric for longevity. VO2max is the measure of our cardio respiratory fitness, meaning how fit are you and it's a direct measure of how healthy you are and arguably how long you are going to live. So in today's episode, we are going to go into the science of VO2 max and the best person to interview regarding this is Brady Homer. Brady received a master's degree in human performance from the University of Florida. He is an endurance athlete and a full time science writer and researcher. Brady is also a good friend of mine and somebody who I'm so honored to bring on the podcast because he is the best person that I know to interview when it comes to the science of VO2 max. So we are going to learn about what it is, we're going to learn how it relates to healthspan lifespan. We're going to really understand what it does from a heart health perspective, what it does from a brain health perspective, how our VO2 max declines every decade that we get older. What are the correct ways of testing this, whether it's in a lab or outside of a lab. And we of course are going to touch on the best protocols to increase our VO2 max so we can perform better, think faster and live longer. So I hope you enjoy the episode. If you haven't done so yet, please go through and smash the follow button on both Spotify itunes and on YouTube. We'll link YouTube below and if you haven't written a review, please go through and do it really only takes around 30 seconds of your time. Brady. Finally, we're here. Welcome to the Neuro Experience podcast. It's going to be a very detailed podcast. I've been waiting to get you on the, on the show for several reasons. One, we've been connected through Twitter for quite some time. I love your Physiology Friday newsletters. You've, you've got so much information to share, all highly credible. And it's on a topic that I love, which is VO2 max, the intricacies of it, how it relates to longevity, peak, human performance. And I have to say I got a lot of this information that we're getting today from your wonderful book. So before we get into the crux of it, why don't we, you know, act as if I don't know anything about you and give the audience a bit of a background on you.
- [03:26]
B
Sure thing. My degree, my background is in exercise science. That's what I got my undergraduate degree in. And then I have a graduate degree in human performance. I just graduated with that last fall. And so I would say I was involved during grad school in some clinical research, primarily regarding cardiovascular exercise physiology. So the effects of aerobic exercise on endothelial function, cardiovascular health, things like blood pressure and whatnot. I actually was a part of several studies on that. So that's kind of, I'm a little bit more formally trained in that, but more broadly, you know, I, I have an education in just exercise physiology, exercise metabolism, a little bit of strength and conditioning. Not a ton, just because I didn't do a lot of applied things like that. But so just a broad background in exercise and that stems from my interest in exercise. I'm also an endurance athlete. I competed in cross country track and field in high school and in college. And then I continue to participate in endurance sports now recreationally. You know, I, I'm decent still, but you know, I'm not a professional runner or, or anything like that. But currently what I do, I write on substack, just about topics related to science, health, nutrition, performance, things like that. As you mentioned, I obviously, I wrote a book last year, compiled actually just kind of a bunch of my blog posts on vo2max and was able to turn that into a short book on VO2 Max, which has gotten some pretty good feedback. And I guess you've read it, so I appreciate that you've read it as well. And I also work full time for a company called examine.com and my role There is a researcher I write about mainly nutrition and supplements. So we are a website dedicated to telling people what works and what doesn't when it comes to their health. Regarding, you know, if you're interested in should I take this supplement or not or does this particular diet work for weight loss? We write about all of those topics based on the most recent up to date evidence. And we don't sell supplements or sell anything on the site other than just memberships so people can read our content. But I've been working for them for about two years and so there's a lot of overlap with that with my job at Examine and what I do on my substack. Just reading about science and writing about that all the time, it's something I find very enjoyable. So these days my expertise is kind of a lot less focused on one thing. You know, I'm not like an endurance performance coach nor am I doing actual clinical research, but I'm just exploring all these topics. If it relates to like human health and performance and science, I'm, you know, trying to write about it and understand it and, and chat about it with people like you.
- [06:13]
A
Yeah. And you do such a good job and it's an area that I love. So you and I share something very similar. I was an endurance athlete and I was a triathlete, which sparked my to get into my first degree, which was exercise physiology as well. And it was at the tender age of 18. That's when I first, I won't, I won't reveal how many years ago that was, but that's when I first went into this whole exercise physiology field. You know, I was both a practitioner, I was, you know, training three sports. But then I was also learning about what I was doing very different. You know, we were learning from textbooks back then. And I actually remember looking at the, at a VO2 max test being done. And that was, that was quite some time ago. And we've definitely advanced since then, advanced in the technology that we're using now. We can do it portably, if you will. Advanced in our knowledge of it. I never heard the word longevity back then. I never heard how VO2 max relates to health span and lifespan. We, we learned it from an ex, from a cellular function, endothelial function, heart health. But I didn't really understand it from a longevity perspective. Beautiful thing about it is when you rip it apart for what it is and you really understand the science of it, you can keep learning. Like even with your book, there was so many things that opened my mind up to energy expenditure and VO2max decline and maximal heart rate decline. And so it's just, it's ongoing and then with new research that's being published, it makes it an exciting field, which is why we can focus this entire episode literally on, on the science of VO2 max. So with that said, before going into the actual test, why don't we first lay the ground for ATP mitochondrial health and I guess energy production?
- [08:09]
B
Yeah, sure. So you know, we can maybe go as as detailed or keep it as like surface level as we want or maybe like a little bit of both. But you know, if we think about energy metabolism or the production of like energy in our body, in our cells, so most of that occurs at least you know, during resting in, in the mitochondria. People will know at the mitochondria, colloquially referred to as the powerhouses of our cell. That's how like we, you know, learned them in, you know, whether it was high school or you know, elementary school or whatever. I don't know if people are learning about the mitochondria in elementary school.
- [08:41]
A
It's so underappreciated for sure, for sure.
- [08:44]
B
We just learned a bit about them as like these little bean shaped things that produce energy and you know, not to sidetrack, but they're actually not even shaped like beans. That's a total like misconception. They're actually like this mitochondrial like mesh like network type thing that they form. But anyways, I digress. So the mitochondria is where our energy is produced and we use two substrates primarily to produce energy, Carbohydrate and fat. Under certain conditions we may use protein to produce energy, but that's, you know, very rare if you know, for like under starvation conditions or something like that. Our body might use protein or amino acids to, to produce ATP. But ATP, what is known as the energy currency of our cell, we need it for muscular contraction. We use breakdown fat and carbohydrate to produce that in the mitochondria. So fatty acids, they undergo beta oxidation. Glucose is broken down. I say carbohydrates. It's actually glucose. That's you know, that energy substrate, not carbohydrate. But glucose is also broken down, Both of those broken down into something called acetyl coenzyme A that enters the citric acid cycle. Krebs cycle, TCA cycle, goes by many names to produce ATP in the mitochondria. And then there are also electrons that are produced during those processes which are used in the mitochondrial electron transport chain. Something called Oxidative phosphorylation that also produces energy. Then those would be aerobic energy producing processes. So aerobic meaning with oxygen. So they are oxygen requiring processes to produce energy. Um, and so again we're producing energy during aerobic, using aerobic respiration, primarily at rest, at low intensity exercise, um, and then at higher intensity exercises or exercises that don't demand oxygen, like heavy weightlifting or something like that, we can produce energy anaerobically. So without oxygen. And that primarily occurs through process called glycolysis. So that's the breakdown of glucose, anaerobic glycolysis. And then we also have a system called the ATP PCR system that produces energy anaerobically. And that's where molecule called phosphocreatine. So creatine and a phosphate molecule, the creatine donates that phosphate to adenosine diphosphate, produces ATP. And so there's a lot of hype and like talk about creatine lately and we may not, probably won't get into that. But one of the reasons why it seems to be so beneficial is because it's supplying substrates for this PCR system and it might enhance like energy production in particular in the brain, which is kind of cool. Um, so again, just to kind of reiterate that we have aerobic energy production, anaerobic energy production, at any one time, we're using, you know, a little bit probably of both in the terms, you know, it's, we can produce energy aerobically and anaerobically. Even when we're doing primarily aerobic exercise, we may be producing a little bit of energy anaerobically. But yeah, those are kind of, kind of the two main ways and areas where energy is produced in the body.
- [11:52]
A
So put simply, when we ingest food, whatever food that may be, that then gets broken down via, goes into the mitochondria and then our mitochondria end up using that to produce energy.
- [12:05]
B
Yes, exactly. And obviously, you know, from when you ingest that food to when those, you know, the carbons are broken down and used to produce energy in the mitochondria is a lot of lengthy steps. So it's not just automatic, you know, eat and then, and then energy. But you know, we probably don't need to go into all of that detail. That can be a whole podcast in and of itself. Probably.
- [12:24]
A
That can definitely be a podcast in and of itself. I'm going to actually read a quote from your book to set the scene for the next question. The fantasy of maintaining youthful cardiovascular fitness throughout Life may be just that, a fantasy. As it turns out, there is a consistently observed and linear decline in VO2 max throughout life, no matter how active you are. When I read that, I was like, like, oh, great, that's just. That's just great. It is depressing. But so what is it about the field? Like, what, what is VO2 max and why is it so important? And why is it so essential for us to understand?
- [13:05]
B
Yeah, sure. So despite it's like increasing in popularity lately, the, you know, the concept or the physiological, I guess we call it a phenomenon of VO2 max isn't necessarily new. I mean, it was discovered actually, I think last year it just turned. It had 100, it had its 100th birthday, I guess, since the discovery of, of VO2 max. So it's, you know, it's been well known in exercise physiology for literally a century, but it's just becoming popular now, recognized for its role in health span and longevity. But what VO2max is, VO2max is the maximal rate of oxygen consumption that your, I guess, maximum rate of oxygen consumption for your body. And so during exercise to exhaustion. And we can go, we'll go into probably later, like what a VO2 Max test looks like, but you eventually reach a point where your body cannot consume any more oxygen and use that to produce ATP. And so this would be indicated by, when you're doing a VO2 max test, there's a line that's going up indicating your oxygen consumption that will eventually plateau even if you continue to exercise harder. So it's not just a linear increase in O2 consumption. It, it eventually levels out. Um, and that would be your view to max, because your body, you know, despite you say running faster or cycling at a higher power output, it can't consume any more oxygen. So that's your VO2 max, the maximal rate or VO2 peak or VO2 peak, I guess. Right. And there are a few different indicators whether like, somebody gets their VO2 peak or their max. They're, you know, they're important to like, distinguish because sometimes if you're, if you're reading a paper that will report participants VO2PEAK, that essentially just means that they didn't meet the Criteria on the VO2 Max test for it to be a quote, a true, quote unquote max test. So the maximal rate of oxygen consumption and why it's important is because, you know, a long time, for a long time, it was just recognized as like, oh, runners and cyclists, they have a high VO2 max. So therefore it's important for endurance exercise performance. But it reflects now kind of what we're realizing, why it might be so important for, for like, health and longevity. It reflects your body's integrative ability to produce energy to take up oxygen from the atmosphere, so your lungs to take in oxygen for your heart and your vascular system to distribute oxygenated blood to your skeletal muscle, your skeletal muscle to take up the oxygen from that blood and then turn that into ATP. So it's not just, oh, you have a strong heart, so your VO2 max is going to be high. Well, that's one component of it. But it reflects again, just like this integrative ability for your body to take oxygen and use it. And you're not going to have a high VO2 max. If you are unhealthy and your body is not in good metabolic condition and your heart is not in good metabolic condition, you need kind of all of these parameters to be met to have a, a very high VO2 max. And so that's why it's kind of gaining notoriety as this important predictor, probably one of the strongest predictors of, of like lifespan and, and health span.
- [16:19]
A
Yeah, I, I gen, I, I genuinely think that it is, is the greatest metric that we have for longevity. I think it outweighs to a small extent, it outweighs strength, even though strength comes, you know, very near in second. However, if, you know, arguably, if you think about VO2 Max, and this is the state that I think about it, it's not the score that we're looking for, it is the journey that it takes to get there. And if you look at all of the different biomarkers, such as, you know, we obviously, cardiovascular wise, we want a low APOB and LDL C. Okay, let's just say we have another metric. Let's just say we have a low or we're vitamin D deficient. You know, arguably you could take maybe 5,000, even 10,000 IUs, which I don't recommend, but let's just say you do. You could up your vitamin D levels and it could, you know, drive that up in the matter of a month or two. However, if I was to come in for a VO2 max test up and then come in again a month later, it's not that you're going to drive up that VO2 max. Like you have to have a big engine in order to get there. And that engine involves doing maximal work, which we're going to go over. It also involves maybe doing some steady state cardio as well. It also involves, you know, metrically if you're going to look at like sleep and energy production, how well your mitochondria functioning. So it doesn't just mean you're looking at this. This one score really is an overview of so many different structures in your, in your life that's going to aid in how well you utilize energy at 80 years old, how well you can get up out of bed, walk to the bathroom, maybe pick up your grandkids, maybe go for a walk. So it represents so much.
- [18:10]
B
Yeah. And that is why too that I think there's a lot of talk about. I think one of the more probably one of the most measures and most measured and most studied metrics probably in the longevity space is grip strength because it correlates so well with, with all cause mortality. But and I'm not discounting again, like you said, strength is obviously important for reduce improving health span particularly. I do think that maybe VO2 max is probably a better indicator because with something like grip strength, you could train just your grip strength to like almost game the system. So, oh, if I wanted to say improve my grip strength to increase my, you know, or reduce my all cause mortality risk, I can just train my grip strength day in and day out with and neglect all the other like muscles in my body. And therefore if my grip strength improves then I should in theory live longer. But you know, what does your grip strength say about your lower body strength? I mean, it probably has some correlation because a 70 year old with a high grip strength probably is in decent shape and they probably have good overall strength. But it may not necessarily indicate like that they're at a lower risk of falling or that they, you know, have, you know, that they're in good cardiometabolic health whereas VO2 max. And again, you know, my bias is coming out here, whatever, but you can't have a high VO2 max. You can't like game the system when it comes to like VO2 max. Because your body, you know, you're teaching it to use energy and produce it more productively. Your increasing the ability of your heart, you know, the health of your heart and your blood vessel function, your endothelial function. So it's like you, it's more integrative, I think than a single measure like grip strength or something. So if we had a measure of whole body strength, like a composite measure, I think that would kind of be something similar to VO2 max. But all the talk about grip strength, I think it's just like, is it necessarily the grip strength that's providing utility or is Grip strength probably just correlating with like, oh, those people probably have more muscle mass and, you know, maybe engage in exercise more at whatever age they're, they're measuring them. That's just kind of my opinion on that.
- [20:15]
A
Yeah. And look, I, I often go between resistance training and cardiovascular training when it comes to brain health, as you know, that's my area. And I've just got a, I've got a paper coming out really soon on the effects of resistance training on mild cognitive impairment. And what we're seeing is that, yes, both aerobic and resistance training, both, both are extremely important. But what, you know, I argue even in that aspect as a subtopic, that cognitively, you know, we want to be looking at strength training, but that's for another episode. So keeping with that theme, actually with brain health, I want to talk about blood flow and therefore I want to talk about the arterial system. If we increase our VO2 max and we arguably get fitter, since it is a measure of our peak respiratory fitness, what is this doing in terms of blood flow, in terms of artery health, in terms of like even cardiac remodeling, what is this doing to strengthen our cardiometabolic system?
- [21:17]
B
Yeah, so one of the main mechanisms by which endurance training. And we'll lump together kind of endurance training here as, or maybe aerobic training as high intensity interval training and lower intensity, like steady state training. So we'll call it aerobic exercise training. I guess one of the primary mechanisms by which it increases VO2 max is by remodeling and strengthening the heart. Um, so cardiac output is the product of heart rate and stroke volume. Stroke volume is just the amount of blood that your heart can pump each beat. And so increasing VO2 max often involves an increase in cardiac output because one of the, if not the main limitation for most people, especially highly trained athletes on VO2 Max and is the ability to deliver oxygen to skeletal muscles. So it's not the ability to take in oxygen from the atmosphere. Like with their lungs, that's typically fine. The lungs are actually overbuilt for exercise. So we have very well developed lungs. Unless you have a pulmonary condition, it typically isn't a limiter for VO2 max, but cardiac output, it seems, is one of the main limiters. And so when we do any type of aerobic exercise training, high intensity interval training, low intensity training, our heart remodels, or left ventricle gets larger. So the, the size of the ventricle, the inside gets larger and the muscles actually get a little bit stronger as well, and this is known as eccentric hypertrophy. There are kind of two types of heart hypertrophy that occur. One is concentric. That's not necessarily the type that's typically seen as beneficial and can kind of occur in. In conditions like heart failure, where the heart walls just get bigger, but the ventricles doesn't actually dilate, so it can't hold more blood. But eccentric hypertrophy with endurance training, that's often one of the main adaptations that occurs. So your ventricle gets larger, it can pump more blood with each beat, and your cardiac output increases. So that's definitely one of the main mechanisms. That's why you also see athletes with very low resting heart rates. Because at rest, at rest, you know, if your cardiac output at rest stays the same. You know, I just mentioned cardiac output is the product of heart rate and stroke volume. If you have a larger stroke volume, more blood pumped with each beat, your heart doesn't need to be as fast. So very low resting heart rate typically indicative of, like, a higher stroke volume. Um, so regarding the vascular system, though, in response to endurance training, a few things happen. So endothelial function, so the function of larger arteries, those are typically measured like in the arm or the femoral artery. We can also measure that carotid artery, like blood flow. So one of the benefits on. On brain health, but overall, exercise is just going to improve the ability of our arteries to dilate. When something called shear stress increases. Sheer stress is basically just blood flowing through the walls of the arteries. It is sensed by the endothelium, which is the inside of our arteries. It releases nitric oxide. People may be familiar with nitric oxide, and that dilates blood vessels. So when we exercise, our ability to do that, our ability of the arteries to dilate increases. Endothelial function improves. And that's also one way that Exercise can improve VO2 max, because you're improving your ability to deliver then blood to. To skeletal muscle. But something also occurs at smaller blood vessels called capillaries. So we get capillarization in response to endurance training. So capillaries increase in number, but also, like, their connectivity kind of improves. And so capillaries are where actually oxygen exchange occurs. So that the small blood vessels that are literally, you know, in contact with the skeletal muscle, their surface area is. Is very large and they're very thin. So oxygen can diffuse easily from blood into the skeletal muscle. So when we exercise again, one of the other main mechanisms is improved capillarization. And that also allows us to distribute more blood to skeletal muscle to increase VO2 max. So those are mainly kind of the three main pathways by which when we exercise, VO2 max increases. It's going to be a stronger heart, more cardiac output, so you can pump more blood to the rest of your body. You can deliver it more efficiently because your endothelial function improves. Then you get increased capitalization. You can deliver more oxygen to, to skeletal muscle. You'll get some improvement in like the lungs. But again, like I said before, it's kind of secondary. You know, there are a bunch of these like lung train and respiratory muscle trainers out there and those can help. But in most people the lungs are pretty overbuilt and doing something like lung training may not necessarily improve your VO2 max. Because if you don't prove improve anything downstream of your lungs, then you're really not going to be able to, hey, you might get more oxygen in every time you breathe, but where's that going to go? You may not actually be able to use it.
- [26:14]
A
Yeah. And during this entire process you're indirectly having an effect on the brain because we're evidently shunting blood to the brain and we know that the blood is delivering the oxygen and nutrients that the neurons need to survive. But when it comes to heart health. And you mentioned left ventricular stiffness and not hypertrophy. Oh, was it hypertrophy?
- [26:35]
B
Hypertrophy, yes.
- [26:36]
A
Hypertrophy, yes, that's right. There was a really great study which I'm sure you've come across from Ben Levine's group where he showed that he actually reversed left ventricular stiffness in 50 year old. I think, I think it was 50. Yeah, he took 53, 50 year olds and he put them through four hours of maximal exercise per week, which is a lot, I must say. However, what he found over the course of two years was that he reversed the effects of the age related decline that our heart endures. And essentially he took the 50 year old hearts which then looked like a like 30 year old hearts. I thought that that is absolutely. That is medication right there. That there is medication. So you could argue that exercise is the elixir to health and vitality and longevity.
- [27:30]
B
Yeah, I would totally agree with that. And Ben Levine, his group does so much and you know, during graduate school, I mean I read so much of, you know, whether it was like reviews hero or studies that came out from his has came from his lab because in what, you know, there are multiple studies showing kind of like similar to those results that you just presented on the reverse, reverse kind of heart aging But I mean, if you take any older masters athletes, you know, 50, 60 year olds who have been exercising like their whole lives, and you compare them to just a group of young, healthy adults, typically their hearts, their blood vessels, they look similar to younger adults and they're, you know, way better than age matched adults who don't engage in exercise. So it can, yes, reverse. You know, I, I hate the word. And you made too, like anti aging. I mean, it's, it's an awful word because it's like we're not actually aging backwards. We're, you know, but it's, it's fun to say and I use it all the time anyway. So anti aging, I mean, exercise is anti aging both in that it can reverse some of that stiffness in the heart, in the blood vessels and the arteries, and it can prevent some of that age associated decline too. So, you know, there are some people who exercise from the time that they're 20 into old age. It's not necessarily that they pick up exercise, say at an older age. And so if you continue to exercise, you can prevent some of that decline as well. So exercise kind of works, works in, in both ways too. But yeah, the, the studies that Levine does, and that one in particular was, was pretty remarkable. And I'm sure, you know, you're the, you're the brain expert here, but I'm sure you see similar things with the brain in terms of, of preventing cognitive decline, reversing cognitive impairment. With age, I mean, the effects are just all over. But a lot of it does just it, A lot of it comes down to the effects on the blood vessels, which, which I think is kind of fun. I mean, we think of the effects on brain health, but I think most of that is also just due to the fact that you get more brain blood flow. I mean, if we don't have blood flow somewhere, we're not able to produce energy and metabolism in whatever area we're talking about is going to decline.
- [29:32]
A
Thank you Inside Tracker, for sponsoring this episode of the show. We talk all the time about optimization and you can do a whole bunch of things through diet, exercise, and proper sleep. But if you aren't measuring the impact that it has on your body, then you are missing out. InsideTracker provides you with personalized plans to improve your metabolism, improve your sleep, optimize your health for the long haul, and most importantly, it analyzes your blood and your DNA. So you have to understand where your biomarkers are. For example, Apob, this is an extremely important biomarker. It's linked to cardiovascular disease. You must know these numbers if you care about living, if you care about living well and living long. So InsideTracker is an easy way to get these things done. And they also offer tools for professionals. I know that I have a lot of professionals listening to this. I know I've got a lot of coaches listening to this. InsideTracker Pro is a no cost platform that allows your clients to share their InsideTracker analysis with you so that you can tailor their health protocols and training based on their results. Just go to InsideTracker.com Louisa. You can get 20% off the entire InsideTracker store. Just use code Louisa20 at checkout. Yeah, and arguably it is now seen or it's now seen as a vascular disease when you look at Alzheimer's disease, because it genuinely really is and it's, it's just remarkable to see what happens to the brain as we age. Even, you know, in, in instances such as hypertension, which dramatically just kill off the capillaries. So I wonder if, though, interestingly you mentioned increasing capillary beds. I wonder if the capillaries are, I say capillaries Australian. So forgive me, I wonder if they are actually also increasing, increasing in the brain when we exercise. And that was actually going to bring my next question, which was around angiogenesis, if that occurs during, during steady state and, and when you're actually exercising as well.
- [31:41]
B
Yeah, that was. I think that it's kind of lumped into the capillarization. I mean, angiogenesis just refers to, to the growth of new blood vessels. I think there's some debate and maybe a little bit rough and not up to date on this literature, but angiogenesis, you know, I think the idea of whether we actually grow new blood vessels or whether the connections between existing blood vessels improve. I think there's a debate on that. I think the latter seems to be more true. Like they may sprout, the blood vessels we have may sprout and kind of connect to one another and improve their ability to distribute like blood. But I'm not sure the idea of like growing new blood vessels is too well established. So angiogenesis may refer to more like a sprouting of, of, of blood vessels. But I'd have to get more up to date literature on that. I haven't read that in a while.
- [32:27]
A
It's very comparable to when a lot of people on the Internet, which, it really bugs me when they say, oh, this, you know, lion's mane improves or helps with neurogenesis. I'm like No, I don't think it does, but it does help with synaptogenesis, which is, you know, literally the, the connections, I don't think. And I said, if that were true, I think we'd all be going out eating tons of mushrooms to just get bigger brains. Brains. It doesn't, unfortunately, biology doesn't work as simple as that. Okay, moving on. I want to talk about actually the metrics and the. And I've got an. I've got a graph that I'm going to pull up and talk about how. Because one of the most notable graphs that I've seen, you know, really benchmarks you in terms of age and gender and it goes into, you know, you can do a below average, average, above our average, and then elite. And I always aim to be either in the elite section, which sadly I'm not, or just I want to try and get below my age group. So I. Let's talk about the highest recording VO2 max, which is most likely going to be from a cyclist. Correct.
- [33:37]
B
From a cross country skier, I believe. And I think now though, that may need to be updated. And I'm Matt, I did not save this tweet, but someone yesterday, the coach of one of the top triathletes in the world, I believe, tweeted out results of a VO2 max.
- [33:54]
A
Is that Igor?
- [33:55]
B
Yes, I believe that is who it was. I think he recorded like above a hundred on a VO2 max test or something like just yesterday. Yeah, something like that. Or in the high 90s. So 99, 98. Before that, the highest ever was. Yeah, somewhere around like 90. Oscar Svensson, I think he was a cross country skier. The reason why it's cross country skiers, they're obviously incredible endurance athletes. But what seems to be unique about cross country skiing, as opposed to, say, running or cycling, is that it is truly whole body exercise. And so these guys are probably typically a little bit more well muscled maybe than say a runner or a try or, you know, a cyclist or even a triathlete. So because, you know, when you're cross country skiing, you're using, you know, legs, you're going to be massive, but also your arms because you have the poles that you're using during cross country skiing. So that tends to be why they have some of the highest recorded values. But yeah, several. Several recordings in the 90s for males, several in the high 70s for females. Joan Benoit Samuelson, the Olympic marathon runner from the United States, she recorded one of the highest for, for women, I think. But yeah, values in the 90s for men are uncommon, but there have been a few. So some of the highest recorded are going to fall in that area, which is ridiculous.
- [35:16]
A
So what is yours? Do you have. Have you done yours lately?
- [35:19]
B
I have. So I. Two years ago, I think I did a VO2 max test and I've had probably two or three done in the past. All of them have fallen somewhere between 75 and 80.
- [35:30]
A
And you're probably going to get better and better.
- [35:32]
B
Maybe. I don't know, I feel like I might be at my peak of VO2 max and, you know, maybe we'll get into this, but VO2 max is clearly important. But I think if. If I'm looking for myself to, to improve my performance, I don't think that's going to come from improving VO2 max, but improving rather my probably running economy or something like my lactate threshold and things like that. Um, because what. I don't know, the benefit for me of going to. From 80 to. To like, 85, what, what that might be, um, it might take too much. Too much, like, volume training and I could probably focus on some different things.
- [36:05]
A
So I've seen. I've seen some research. Research. I don't know if it was in your book or if it was somewhere else or if you know the exact data just to actually, like, break it down for everybody, just to really understand the real importance of it. Do you know what level you need to have, what metrics, like what VO2 max you need to have in order to just. Just walk around the block or maybe just get up out of bed and just to maintain everyday function?
- [36:33]
B
Yeah, that has been established to be somewhere around 15. And so I guess for context, like, when we say all these numbers, what we're referring to, 15 would be 15 milliliters of oxygen per kilogram of body weight per minute. So that's a. A relative VO2 max, and it's typically expressed relative to body weight. We can also express VO2 max just in absolute terms, so, like, liters per minute. But typically, if we're looking at rankings and scores, it's going to be relative to body weight, which. Which obviously makes sense because if you're a larger person, you're going to have a higher VO2 max in absolute terms just because you're. You're bigger. Um, but, so 15 mls per kg per minute is. I kind of refer to it when, when people ask as the like. Like the frailty threshold. So if your VO2 max is below 15, you have trouble engaging in activities of daily living that just require that amount of, you know, energy and oxygen consumption just to complete them. Like you said, walking around the block or going up a flight of stairs. If your VO2 max is below that, you're going to have trouble engaging in, in those activities.
- [37:38]
A
Oh, that's really interesting. Which is why we need to, you know, that's just baseline. Who would you categorize as having a less than 20 VO2 max then? Is it somebody at the age of 80?
- [37:51]
B
I mean I wouldn't say just because you're 80, you're probably going to have a VO2 max that low. I mean it typically will take some sort of like disease state. So someone with heart failure maybe for instance, or I mean someone who is incredibly detrained or has been, you know, subjected to bed rest for, for a few years. So I mean I think there are plenty of 80 year olds out there again who are fully functional and you see them walking around and doing things. I mean they probably have VO2 maxes in like the mid 20s. Someone below 20, I mean these are going to be very, very sick probably individuals and again having trouble like doing things and you're going to get out of breath like walking up a flight of stairs. So you know, your typical again I don't have all the data on this but your typically typical like 80 year old, 70, 80 year old is going to have a VO2 max in you know, 25, 30 maybe, something like that.
- [38:41]
A
Yeah, I've just pulled up the graph and it's the manned mansasia et al 2018 graph. And so I'm looking at the metrics here. So for females around around 30 to 39, you're looking at having a VO2 max score of 39 to 48 and that would be high. An above average would be 34 to 38 and above 49 would be elite. So I am trying my hardest to get to over 50. What did you say yours was?
- [39:23]
B
Between 75 and 80.
- [39:24]
A
Okay, yeah, mine's. I don't know what age group you're sitting in, but yeah, I'm 30. Okay, well look, you've got a bit, a bit of age on me. But that brings me to my next quote for you and which is because it's been shown that increasing your VO2 max by just 3.5 mils per kilogram per minute reduces the risk for all cause mortality by 11%. This much of an improvement is attainable in six to eight weeks of focused aerobic exercise training. So that's interesting. So let's talk about actually before we get into like increasing. I actually want to talk about the actual lab test that you can get done. So what does that actually do? I, you know, at neuro athletics, we, we have these. It's not a lab, it's a, you know, I've got an exercise physiologist on board, Jonah, and he does all of the testing. It's not in a lab. He's got a portable, I think he's got the portable one. But it's, you know, it's probably the, the best portable one that we can think of. So why don't you just break down on the actual test and we'll do it from a treadmill perspective as well. Thank you Mud Water for sponsoring this episode. Mud Water is a coffee alternative which tastes like a cow and chai had a beautiful baby together. It's the solution to your coffee jitters if you are a coffee drinker. It's got four functional mushrooms, each of which were chosen for a specific purpose. It's got cacao and chai for a hint of caffeine, lion's mane for focus, cordyceps to promote natural energy, and both chaga and reishi to help support a healthy immune system. It's 100% USDA organic, kosher, vegan and gluten free. So if you are looking for a delicious alternative to your morning coffee, this is where to start. Right now you can save $29 plus get a free sample of a creamer and a free frother by going to the link in the description below or heading to mudwater.com Louisa so if you want your free frother and free samples of coconut creamer and sweetener, you can go to the link. You can get the samples all for free. That is mudmudwtr.com Louisa sure thing.
- [41:43]
B
Yeah. So the actual test typically, and I would encourage everyone, just as like a side note, I mean, it's becoming more widely available. I mean if you live anywhere with like a university that conducts research of some, some kind and they have like an exercise physiology or a physical education department, I mean it's, there's probably a good chance that they are either running a study or like you can buy a VO2 max test for probably, you know, 200 or something like that. So I don't think, not even, I.
- [42:11]
A
Think they're about 150, probably a bit cheaper.
- [42:12]
B
Now I know here in Austin I can get one at University of Texas. I think they charged me like 150, but they'll give you the, the full kind of breakdown and we'll sit down with you and talk about and they'll print out your report. So it's very, it's very cool. Cool. It's worth it. You know, the, the information you get from that is incredible. So what you'll do for, for the test, you know, depending on where you go, they may use a different protocol, but one of the more popular protocols, again, we'll just use a treadmill as kind of the. The reference here. It's known as the Bruce Protocol. And without naming specific numbers, sort of like what the test involves is you'll do a short warmup on the treadmill of six minutes. And during that six minutes, it'll kind of just be used to do. To get a warmup, but then also to establish a speed where your heart rate is about 65 to 70% of your age, predicted maximum heart rate. And that'll just be flat on the flat portion of the treadmill. And then once that test starts, every two and a half minutes, the treadmill is going to increase. The grade of the treadmill is going to increase and the speed is going to increase. And so I believe it's about a half a mile per hour. Um, I know you may speak in kilometers, but I'll use mile per hour, half a mile per hour, two and a half percent grade every two and a half or three minutes. And so you'll just do that until you're unable to. To continue exercise, until you give up, till you're rating as a 10 out of 10 on the, you know, this sucks, like score. And during that test, you're going to.
- [43:45]
A
Be fitted with gas out. Really?
- [43:46]
B
Yeah, literally till you gas out and you can't go anymore. During that test, you will have a heart rate monitor on a chest strap. You may wear an ecg, but probably not unless you're doing like a stress test. And they're trying to look for like a heart arrhythmia or something like that. That can get pretty burdensome because you're wearing a ton of stuff and it's like, hard to run, so it's not really fun doing that. But you'll have a heart rate monitor just so they can measure your heart rate during the test because you want to see what your maximum heart rate is and if it's close to your age, predicted maximum heart rate. And you'll also be wearing a mask. So some of these masks will go over your entire face kind of like that. Some of them will just be like a snorkel mouthpiece. And then you'll be Wearing nose clips. Some of the more advanced ones, they just go over your nose and mouth so you don't have to wear nose clips, which is nice. It can be kind of claustrophobic if you have those nose clips on. Um, it's also not very fun. So you'll be wearing a mask. And how VO2 max is measured during this test is there's something called indirect calorimetry. So that mask allows, you know, it's measuring airflow, and it's able to measure the amount of air that is coming in. So when you breathe in, the amount of air that you're exhaling, so the volumes of air. And then also just with the known concentrations of. Of carbon dioxide and oxygen in the inspired air, and then the ability to detect the concentrations of carbon dioxide and oxygen in the expired air, we're able to calculate how much oxygen your body utilized. So obviously, the difference between what comes in and what goes out is what your body used up during that test. So again, that's called indirect calorimetry. But that's how your VO2, how your oxygen consumption is, is. Is measured during that test. Um, the test typically lasts 12 to 20 minutes. It's not very long, but it does suck because you're, you know, you're going as hard as you can. Um, and the. And the researchers will often push you to your limits. They'll cheer you on at the very end just to try to get that last, like, 30 seconds out. Cause every. Every 30 seconds or so can. Can make a big difference. Just if you want to go up, like, a point or two on that. On that VO2 max test.
- [45:55]
A
Now, I have to just understand some confounding variables in there. What if you come in and you're sleep deprived? What if you come in and you're like. And you haven't eaten or you're dehydrated or maybe you're a bit sick?
- [46:08]
B
Yeah, I would recommend, you know, don't do it when you're sick. Try to get a full night of sleep. They'll often try to standardize. If it's for a research study, they'll do their best to standardize. You know, make sure you abstain from caffeine for three hours, don't exercise the day before, don't drink alcohol the night before. We were doing a VO2 max test once when I was in grad school, and the participant came in and they were sitting down, and we were doing, like, the. The intake form before. They actually do some of, like, the research protocols. And. And they were Saying, oh, well, you know, I had a couple shots of tequila last night and we were like, well, okay, you should, you should probably go home today because you didn't follow the protocol that's gonna reduce your VO2 max. So yeah, I mean, if it's your first test ever and you're sleep deprived, you know, you don't have anything to compare it to, but it's probably going to be lower than it, than it otherwise might be because you, it may not, you know, physically reduce your body's ability to produce energy or get a high VO2 max, but your, your motivation and your willingness to push yourself to your max is going to be lower probably. And the way that, that's going to be like indicated again, we, we discussed earlier, Louisa, the peak versus max. So when you're doing that test, we're measuring a few other things. So we're measuring your heart rate and we're also measuring something called respiratory exchange ratio, which is indicative of fuel utilization. It's a ratio of CO2 production to O2 consumption. And then also measuring your RPE, your rating of perceived exertion. How hard do you think this is? And so at the end of the test, three out of four of those criteria need to be met, including the plateau in VO2. So you want to see a plateau in oxygen consumption. You want them to have an RPE above 18 out of 20 on a Borg RPE scale. You want their heart rate to be within, I believe, 10 beats per minute of their age predicted maximum heart rate. And then their RER, their respiratory exchange ratio is supposed to be above 1.1, which is typically indicative of your utilizing Go. You're totally like anaerobic at that point. So if I believe it's, you know, if you meet three of those criteria, you can consider it a maximal test. If three of those aren't met or only a few of those are met, it's a peak. And so if you're sleep deprived, if you are sick, you probably won't meet those criteria. So in other words, you just won't be able to get to your, your VO2 max.
- [48:36]
A
And I wonder also what it would do if you were older. Maybe, you know, let's just take a 70 year old who may be not able to run. Let's say then they would just, you, you just bump up the incline and just get them to walk really fast. It doesn't really matter that you're not running per se, just means that we just have to get you to your peak.
- [48:57]
B
Yeah, most of the time I mean, I've, you know, performed many of these tests, not actually done them myself, but like, ran the test with someone else performing it. And more often than not, the people aren't walking. Granted, most of our research studies were in maybe older adults, but. But because the grade gets so steep, yeah, most of the time these people aren't going to be running. Even when I did a VO2 max test, I was running pretty slowly, but the treadmill was at like a 12% grade. So I mean, you're, I mean, you're working. Um, so yeah, if you can't run, no big deal. I mean, you'll, you'll walk at probably a fast speed, maybe something like three to four miles per hour. And then as that gets deeper, your, your heart rate will increase rapidly.
- [49:35]
A
Yeah, I keep thinking, like, how am I going to get, get my dad in there to measure it? That's all I think. That's all I think about. Okay. Before we actually move on to protocols, I actually want to talk about building your base. So we know that obviously, VO2 max, we have to get to our, in terms of training without, you know, touching on it. We know that we have to get somewhere to our maximum heart rate in order to train it. We need to stress the system for it to adapt as basic biology. But what about the actual engine? And I'm about talking, talking about endurance work. And of course I'm going to bring in zone two, which right now is also. I think we're going through another phase of zone 2 and lactate. So let's just talk about that for a moment.
- [50:19]
B
Yeah, sure. So zone two training, again, if you kind of do research, you'll see a lot of maybe definitions of Zone 2 training thrown out. Um, I think the kind of consensus is going to be like, zone two training is, is an exercise intensity. So maybe that's running speed or cycling power output that elicits the maximal fat oxidation. Um, so it's a very low ish intensity. It's one that you could continue doing for a long amount of time. Um, it's an intensity that you could talk at. You know, there are many definitions because. Or it's the definition, I guess the intensity where your lactate levels aren't increasing, so you're kind of at like a steady state of, of lactate production, you're able to clear that lactate. As most people don't have access to a lactate analyzer to use during all of their exercise tests, typically things like the talk test or are utilized instead because it's like, oh, can you hold a conversation at this? Okay, you're, you're probably at zone two. And unless really, you know, maybe this is controversial, but I think unless you actually have, have like a, access to a continuous lactate analyzer which are not really available or are testing yourself every single day, kind of using lactate to Prescribe your Zone 2 exercises is sort of useless. For instance, if you go into a lab and you get a lactate threshold test done and then use that to prescribe your exercise training, I'm not necessarily sure that that is totally useful because your levels of lactate are going to change on a day to day, on a day to day basis based on stress, based on sleep, based on sleep, based on what you've eaten or whether you're fasted. So I think using kind of these other subjective maybe metrics or just using heart rate again are going to be a little bit better. So if you're looking at heart rate zone two, it's going to be like 60 to 65% of maximal heart rate between 60 to 70%, something like that. But yeah, the, the importance of it is again, like you said, it's foundational, it's foundational work. You know, it improves our lactate clearance capacity, it improves our mitochondrial health health, it improves cardiorespiratory fitness and cardiovascular health as well. And so, but again, I think it's good to think about it as being the foundation. If you think of like fitness, like a, maybe fitness or your training like a pyramid, you want that, most of it, a lot of your training to be that zone two training which is kind of the, the base or the foundation of that pyramid. And you know, athletes have been doing it forever and it's obviously clearly important and important for metabolic health as well. Even if you're not kind of a high level, high performance athlete.
- [52:56]
A
It's, it reminds me, my coach, you know, we 6am just swimming the black line every Monday and I was arguing, I never missed a session. I was, you know, I was training for quite a number of years, a decade actually. And he used to always say to me, louisa, slow down, slow down. And then he said, bad swimmers can't swim slow. He used to always say that to me. And I used to think, what are you talking about? Even when I was running, we used to run and back then I had a metronome in my, I used to wear a headband and he put this little yellow metronome near my, near my ear and he would set it so I would be like going so slow. And I used to think I can like, like I can write an essay while I run because I'm running so slow. And never understood it until race time came and until the summer came in Australia. And that's when we would be doing our brick Sessions and our VO2 Max sessions. We were hardly touching the Zone 2, but I realized how fit I got from the slow. You know, I was running at that. I mean, I'm going to say kilometers. Even though I've lived in the United States for quite some time. I was running like, you know, my Sunday sessions were. And my, I was doing Olympic distance at the 10 kilometer run. My Sunday sessions were like 30 kilometers. I remember just breezing through them down on the water where I used to live. Just breezing through, like listening to whatever I listened to back then. Now if I was to run 30 kilometers, that's around 20 miles, I think I would be like, I can't. I don't think I can justify it. So there is something to be said around zone two, building the, building the base. And I do believe that it does improve the efficiency of mitochondria. Right, and improves efficiency and biogenesis.
- [54:33]
B
Yeah, definitely. And I guess one of the things that I think about and maybe to ask you, do you think that, you know, when you saw those fitness improvements from the low intensity training, I think it has independent effects. But do you think that some of it is maybe due to the fact that doing low intensity training on the easy days allows you to perform a little bit harder on the hard days? Uh, or do you think maybe it's a, it's a contribution of both? Because that's kind of how I often think about it is like, yes, low intensity training is beneficial, but you know, what's actually, you know, that's contributing to my baseline fitness, of course. But if what's contributing to my actual race performance, my ability to run faster, is clearly those higher intensity workouts, which you're not going to be able to do if you're just doing every day, sort of like in this weird gray zone of training. So you need to go easy on your easy day days. That enables you to go harder on your hard days. Not discounting the benefits that are independent to zone like zone two.
- [55:27]
A
But yeah, no, I completely agree, which is why it was so strict and regimented back then. I know my, my coach defined my entire day, seven days a week, for an entire decade. And I think he did that for a reason. You know, I even had at one point he used to put in my Program feet on the walk wall for like 20 minutes per day. And that would just like, I would have my feet on the wall with my, with my other teammates and we'd be just doing it for, you know, an hour a day. It was so weird. So everything was regimented, I think, specifically for that. But I have to tell you, it's the same for altitude training. You know, we would do altitude camps for two weeks and that was just, you know, once out of the year. And when I would come back to Australia, I was just flooring it. I would feel so. Feel such an immense benefit from doing altitude training. So it's, it's the same thing. That's why brick and periodization is really important.
- [56:23]
B
Yeah, absolutely. But regarding your comment about like the, the mitochondrial efficiency. Yeah, I mean it. Doing that is obviously going to. Because again, if you're training at the point where your mitochondria are sort of maximally, you know, at their max, whether, you know, contributing to, to fat oxidation, you're going to improve their ability to, to produce energy. So that is clearly an important training zone to train in.
- [56:46]
A
Obviously we're going to wrap it up with protocols. And you've put protocols in your book which outlines, you know, the best protocols to take, as per the literature. And you nailed it down to the 4x4 principle, right?
- [57:01]
B
Yeah, I did. There's a section in there in, in. Granted this is, this is from a single study that, you know, I included in the book, but it was a neat study in that it compared four different types of training in which were most effective for improving VO2 max. So they looked at a low intensity or a moderate intensity steady state. So just running at, you know, 75% of your VO2 max, a lactate threshold run, which is like a 20 minute run at 85% of VO2 max or heart rate max. And then two interval training protocols. One was 15 seconds on, 15 seconds off off. So kind of like sprint interval training. Um, some people might think of that as like Tabata training. Tabata is technically 20 on, 20 off. So, you know, you have a difference of like five seconds. But these shorter sprints and then the Norwegian four by four, that's kind of the, the famous, you know, the protocol that everybody's talking about lately that in just. That involves four rounds of four minute intervals with like a three minute recovery in between. It appears, you know, both of them in, in that study that we're referencing, the 15 second on 15 off in the 4x4 were, were both pretty effective. I think they increased VO2 max from between like 6 and 10%. The 4x4 did seem to be a bit more effective and other studies have kind of shown the effectiveness of that protocol for improving VO2 max. And it again seems that maybe nothing magical about four minutes, but it does appear that intervals with a duration somewhere between four and like seven or eight minutes are probably ideal for, for increasing VO2 max around again, there's gonna be around like probably 85 to, to 95% of your maximal heart rate, which is hard, but it's doable.
- [58:48]
A
You know, we've sorry to cut off. I think it's important to mention that it's not the time, it's not the four minutes because it's going to take you around a minute to get to the 85% of maximal heart rate. So let's just say it does. Let's just say we start and we get there within 90 seconds. So are we taking that into consideration? So what about, let's just stick to like, how long do we have to spend with our heart rate at 85% of max?
- [59:19]
B
No, that's a good point that you bring that up. So what essentially you're going to do for that protocol is first, depending on the modality that you're using to perform that. So are you going to be on a bicycle or are you going to be running? Find the pace or the power output that will elicit 90, you know, between 85 to 95%. So we'll say 95 for the sake of this 95 of your age, predicted maximal heart rate and then perform those four by four intervals at that pace or at that power output. So to answer your question, you're doing four minutes. You're not spending, you're not spending four minutes at 95% of your maximal heart rate because like you said, it may take you a minute during each interval to get there. So you're not starting the timer. When you reach 95%, you're going to start the timer and then just do four minutes. But you're going based on, you know, a pace or intensity. But that should elicit that intensity of your heart rate. Does that, does that make sense?
- [60:18]
A
Yeah, it does. I use the Step Up a lot lately at the gym. I reached, I mean, if I reached this morning, I got to like 18, which I thought, okay, a. I couldn't keep up it. I was like my, I just reached my peak and it was like. I call them spew sesh. This is what we used to call them in our in training days. We have a spew session coming up, and that's what I called it this morning. And it was just reminding me back then of my triathlon days. And that was, was, you know, it is difficult, but the, the great thing to know about that, and I want everyone else to know is you don't have to perform this every day. You can literally get by with was it 16 minutes per week that can increase it. So that would be doing four by four, four times once a week.
- [61:07]
B
Yeah. And there are also kind of other studies showing there's kind of been this. I think researchers are like always in a competition to find like, what's the least amount of exercise that can improve your V2 max. So there's this increase lately in the sprint interval training where they're doing like 15 sprints of like 10 seconds each and just doing that once a week and showing improvements in VO2 max. So I mean, if you do enough work and you keep it high intensity enough. Yeah, I mean, you can Increase your, your VO2 max in doing that. Um, some of those studies on the four by four, you know, you could improve your max in one week. But I think some of the studies using that protocol will actually have the participants maybe do make two or three of those sessions per week. I know some of the studies that we conducted in the lab, you know, people were coming in three times per week to, to do that, which again, is hard. I mean, it's not a super long protocol. You know, it doesn't last more than, you know, like, say 45 minutes. So you're doing a total of less than three hours of actual exercise per week. But it's all fairly high intensity. You're getting those recovery periods. But yeah, I mean, doing it once a week is. Is good. Doing that three times a week, whether that's sustainable, I think is. Is obviously questionable. So adding a 4x4 to your weekly, you know, conglomeration of Zone 2 training and lower intensity training is definitely something that I think would be beneficial. And again, like you said, it only takes a total of 16 minutes at that. At that heart rate rate, which isn't that. Is that not that long? It feels long while you're doing it. Um, but in reality it's. It's not. It's kind of a small snapshot of your total weekly duration.
- [62:45]
A
And just one last question. If folks don't have a, you know, they haven't done their VO2 max test yet and they don't know their maximal heart rate, would you do the. Just a. Roughly just 220 minus your age.
- [62:58]
B
220 minus age. There's a lot of variability in what someone's max heart rate will be, but it's, it's close enough. I mean, again, I really wouldn't recommend it cause it can be kind of far off for some people. But yeah, if, if you don't know what your max heart rate is, take 220, subtract your age and that can give you probably a decent estimate of, of what your max heart rate is or at least kind of a broad general range. The best way would obviously be to, to find out that heart rate during a, during a VO2 max test. But not everyone is, is able to do that.
- [63:28]
A
Well, Brady, this has been incredible. I've loved every minute of it. I definitely see us doing a part two in the future. You hang out a lot on Twitter. I don't think you hang out as much on Instagram. So I'll link Twitter and I'm going to link your book. I think everyone needs to get. It's such an easy read. I've been reading it on my Kindle, which is my new favorite thing. And is there anything else that you wanted to add there?
- [63:53]
B
If people want to read what I write about, most of that is going to be on substack. Physiologically speaking. Dot com. Yeah, linking it would help because it's. I picked like the worst hardest to spell domain name ever. But yeah, check out the book Find me on Twitter. Say hey. Or I guess it's X now Find me on X and. And then the substack. That's really kind of where you can find me. And yeah, you know, Luis, this was fun. I again, I think we could have like five more of these on just other topics. I mean we, you know, VO2 max for an hour and a half is great and there's so many other topics I think that we, we both have like a mutual interested in. But yeah, this was awesome. And I guess one more thing maybe before we leave. I wanted to mention if people want to try to estimate their VO2 max and don't have access to a test, you can do something called the Cooper 12 Minute Run. I provide that in my book as well. So you can do this stuff on your own without equipment, which is, which is kind of fun. But again, that's my book. So maybe a plug for people to, to check that out to find that protocol.
- [64:51]
A
We'll link all of that. Thank you, Brady, for being part of the neuroexperience podcast.
- [64:55]
B
Yeah, thanks a lot, Louisa.