WHOOP Podcast - Improving VO₂ Max For Longevity and Performance with Dr. Greg Grosicki

Episode Date: July 2, 2025

Looking to improve your VO₂ Max? This week’s episode gives you everything you need to know about one of the latest WHOOP Metrics. WHOOP Global Head of Human Performance, Principal Scientist, Dr. Kristen Holmes sits down with WHOOP Senior Research Scientist, Dr. Greg Grosicki to define VO₂ Max and offer insights on its importance for healthspan and human performance. As part of the How To Series, Dr. Grosicki shares his knowledge on how VO₂ Max affects musculoskeletal load, metabolic flexibility and aerobic capacity, and the important training tips to improve this metric. (00:50) How WHOOP Captures VO₂ Max(05:04) Studying VO₂ Max: Creating The Dataset (6:05) Developing The WHOOP VO₂ Max Feature(9:08) How WHOOP Studies VO₂ Max(10:46) Defining VO₂ Max(12:08) Impact of Musculoskeletal Load on VO₂ Max(19:32) The Physiological Factors Determining VO₂ Max(26:07) Inner Ad(26:40) What Is An Optimal VO₂ Max(31:27) Performance and Increasing VO₂ Max(40:13) Metabolic Flexibility(41:39) Training For VO₂ Max(48:16) Quality of Reps As It Relates to VO₂ Max(49:39) Impact of Training ConsistentlyRelated episodes: Paul Larsen - Zone 2 Training:SpotifyAppleSupport the showFollow WHOOP: www.whoop.com Trial WHOOP for Free Instagram TikTok YouTube X Facebook LinkedIn Follow Will Ahmed: Instagram X LinkedIn Follow Kristen Holmes: Instagram LinkedIn Follow Emily Capodilupo: LinkedIn

What is the definition of VO2 Max? Everyone gives you the same definition, which is the rate at which your body can consume oxygen during exercise. But why exactly does that matter? That, I think, is often what's missing when people define what VO2 Max is, right? You can look in a large language model. You can Google VO2 Max is the rate of which oxygen can be consumed during exercise. Okay, great. Why do we as exercise physiologists care so much about VO2 Max?

Why has it become the most ubiquitous measure in all of exercise physiology? For very good reason, VO2 Max is this integrated metric that reflects all of the bodily systems working together during physical activity or during work to produce energy and to prevent fatigue. And that's why how much oxygen we can consume matters. Dr. Gersicki, welcome back. Dr. Holmes, still to be here again. So pumped to talk about VO2 Max and to just get into all the nitty gritty details. We're going to start off by talking about the rigor behind the feature.

I think that's really important to set the stage in terms of just the credibility of the data that folks are getting, I think, is a really important place to start. And frankly, we're really proud of it. And you had such a huge part in making sure that we had the level of rigor that we needed behind this feature. So huge shout out to your role in that. And then we'll go in just the how, the why. how to think about training. You know, I really want to talk about, you know, how to back in, I think, for folks who are trying to design a training plan, it's thinking about, all right, how much time do I actually have to train over the course of the week? And if I'm thinking about this 80, 20 ratio,

80% of the time I'm in zone 2, 20% of the time, I'm in zone 5, kind of in that, like, VO2 max threshold. What does that actually look in terms of how I plan my training? So we'd love to kind of back into that just to help people think about their week in a more tactical way. And I think we should probably also talk about just we know strength training is a really important component to kind of overall health and longevity. How do we think about strength training? So if I have a total of X amount of hours over the course of the week, what proportion am I doing, you know, in terms of zone two? What is the proportion of zone five? And then how do I think about my string training in that context? I think giving people a framework of how to think about that

would be super useful. So does that sound like a good plan? Yeah, no, perfect. My favorite conversation as a amazing as a physiologist. So we're a physiological monitor device at our core, having an exercise physiologist who is trained inside our building is obviously really, really important. Talk about just how we created a foundation to be able to train our data in a way that allows us to give you a really good estimate of your VO2 max. Yeah, no, for sure. And one of the things we see, right, is that wearables and companies have been providing VO2 Max estimates now for almost a decade. We are not the first to do it, but there's a reason for that. And that's because when we provide people that estimate, we wanted to make sure we got it absolutely correct.

So how did we do that, right? So our lateness was just due to rigor. For sure. I mean, there's absolutely no value providing our members data that's not actionable and actually accurate. And so we went to the state-of-the-art science to figure out how to do that. There's a paper published by academics all over the world. It's actually a consortium known as the Towards Intelligent Health and Well-Being Network of Physical Activity Assessment Consortium, which somehow they come up with Interlive, which I'm sure they plucked those letters. It sounds really cool. And these are leading experts in wearable tech and particularly estimating key physiological metrics with wearable tech. So they've provided wearable tech companies with valuable information to if you're providing people with resting heart rate, this is how it should be done. If you're providing people with steps, this is how it should be done.

And in the journal Sports Medicine in 2022, they published this really high-impact paper. And if we look at academic journals in the field of sports medicine, sports medicine is as high as it gets. And in this paper, they provided very detailed and specific guidance for how wearable companies should go about this. And when designing this VO2Max feature, we use these recommendations as our Bible. And they provided very specific and actionable ways that we could do that. to give just some indications of things and key considerations there. First, what is the target population that you are trying to estimate VO2 max in? We know it whoop that we're not just trying to unlock human performance,

but we are actually now trying to unlock health span, right? And so that means we're not just providing VO2 max estimates for 30-year-old collegiate athletes or the 40-year-old CrossFit athlete. We're trying to provide accurate VO2 max estimates for people who are. are 80 and people who are 18. So how do we do that? That means when we're sampling people and bringing members and non-members into the lab for these gold standard tests, we need to bring everyone in or else our algorithms aren't going to accurately predict that. So diversity is just an incredibly diverse sample. We need... It's hard, though. I mean, that's a, when we talk about

recruiting for studies, like, that's part of the limitation of most studies is that we don't actually have that diversity that we need to train an algorithm to be reflective of, of this kind of huge span that you're talking about in terms of age and biosex, et cetera. Yeah, incredibly challenging. And the folks in data science thought this through very strategically. Before they did any of the testing, they set out, what are the buckets of people we need? What are the age ranges? What are the fitness levels of the people we want to come in taking these tests?

So it was all very thought out beforehand. It wasn't just, let's recruit, you know, the first 200 or so or more. We know we have more people that we could get. to do these tests. So that's just one of the components. So knowing how many folks we actually need in each one of those buckets in order to have enough data to train an algorithm? Yep, to provide, again, a really accurate measurement for anybody. So talk a little bit about just the metal ball cart, just so people understand what does an actual VO2 max test entail? Yeah. And what are we trying to derive from it? Sure. And that's another thing that's very unique about what we did. And they

specify this again in that paper by the Interlive Consortium. They say that when you're making these algorithms and designing these algorithms to predict VO2 Max, they're very specific about what you need to be training your data against or predicting is a gold standard VO2 Max test using indirect calrimetry. What does that mean? It means we are measuring the amount of air. Someone is breathing out and breathing in. We're measuring the concentration of gas, particularly oxygen and carbon dioxide in the air they're breathing out and breathing in because with VO2 max we know it's how much oxygen someone is consuming per unit time and so it's absolutely essential that if we're trying to predict that we need that to be measured and there's a lot of

different ways to do this when i was teaching exercise physiology we would always start out with submaximal tests and those will look like things like putting someone on a bike at a given workload and looking at what their heart rate response is to that workload and sure we can estimate what someone's VO2 Max is, but our members could just go do that on any sort of bike and predict or estimate their own VO2 Max. And that's not what these members are paying for. And that's not what we gave them. We give them gold standard training data. And just tell just the unit of measurement that we use, just because we'll reference that throughout the podcast just so people can orientate around that unit. Yeah, no, certainly. So V02 Max is measured in a lab in

liters of oxygen per minute. So that's the liters of oxygen that someone's consuming per minute. Now, that's not the measure that we most frequently hear of when we hear about V-O-2 max. If I'm telling you someone's V-O-2 max and liters per minute, it's probably going to be anywhere from 2 to 7 perhaps on the higher end of liters of oxygen per minute. But V02 max, I like to think of as the size of the engine in a car or the size of the engine in the person. And what While understanding how big that engine is is great, what's more informative when we think about performance and also health span is understanding how big that engine is for the size of the car, right? If you and I and someone who's six foot six all have the same size engine, it's

not going to move as fast in the person who's six foot six as it is in you or I who's much smaller, right? And so we most frequently will normalize that for someone's body weight in kilograms. And so when we hear VO2 Max discussed, we hear it referred to as a number that's relative to the size of the individual. And so we hear a number of milliliters of oxygen per kilogram of body weight per minute. And those numbers are going to range from maybe down near 10 to 20 and people who are not as healthy all the way up to very close to 100 in the fittest people on Earth. The endurance athletes. Yeah, the extreme endurance athletes. We'll talk a little bit about that in a minute. Is there anything else about just kind of the metric itself and the testing

that you feel like folks should know? About our testing, I think, I think for sure. We brought in over 300 people to whoop labs to do these tests. There was very strict protocols before they came in as far as refraining from vigorous activity, knowing what they had done in the past, right, controlling, making sure that they're eating and drinking and taking of anti-inflammatory drugs. There are other things that might influence these measures. This is all the very tightly controlled. Before every test, we calibrated the metabolic cart. We bought the best metabolic cart there is, the paramedics metabolic cart. It is the absolute gold standard for doing this. And then after every test, and as specified by the Interlife Consortium, and then they looked at,

I think it was something like 17 independent external validations of VO2 Max, and very few actually verified that the tests were, the individual doing the test had reached their VO2 Max, their true VO2 max. And what's important is that we did that. And so there is a number of different criteria you can look at, four of them that are primarily used. One of them is did the individual's oxygen uptake plateau during that test. What was their self-perceived exertion at the end of that test? What was their respiratory exchange ratio, which is really a measure of fuel utilization at the end of that test? And then how high did their heart rate get? And we looked at every single one of those metrics to validate that the training data we were using for these tests was absolutely gold

standard. So we took the very strictest protocol and applied that to, yeah, our testing. I love that. All right. So I think we have a really good definition of a VO2 max. Maybe just a definition that's not as technical, but just kind of zoom out for the layperson. Yeah. What is the definition of VO2 max?

Yeah. And everyone gives you the same definition, right, which is the rate at which your body can consume oxygen during exercise, which is great. Right. But why exactly does that matter? And that, I think, is often what's missing when people define what VO2 Max is, right? You can look in a large language model. You can Google. VO2 Max is the rate of which oxygen can be consumed during exercise. Okay, great. Why do we as exercise physiologists care so much about VO2 Max? Why has it become the most ubiquitous measure in all of exercise physiology for very good reason? VO2 Max is this integrated metric. that reflects all of the bodily systems working together during physical activity or during work to produce energy and to prevent fatigue. And that's why how much oxygen we can consume matters, because we as human beings, if we're doing work, either sport or just walking to the car, depending on our level of fitness, need to produce energy to prevent that onset of fatigue, right?

We want to be able to sustain a given task. And how much oxygen we can consume is directly related to our ability to produce energy without reaching fatigue. Now, I think people immediately, and for good reason, just think that this is a purely a measure of cardiac respiratory fitness, which it is, but it maybe just kind of talk about your muscle skeletal health and how that might influence this measure. And is it fair to say that your VO2 max is just as much of a measure of your cardiovascular health, I would say the health?

health of your nervous system. Is it also a metric that can give us some inside of your mescal skeletal health? One of the beautiful things about it is it is this holistic physiological measurement that does reflect the performance of all bodily systems, right? And it does reflect the ability of the cardiorespiratory system to deliver oxygen to the muscle, but equally as important, just like you're getting at, is the muscle's ability to take up that oxygen and use it to produce energy. And so if you're okay with it, I think a really logical next step and a cool way for our listeners to understand this would be to just kind of provide high-level overview. What is the equation that we use to determine V-O-2 max? And then I think from there we can use that as a way

to kind of get down into the more liddy-gritty of like, how do you improve it? Love it. Love it. Because I think to understand how to improve V0-2 Max, understanding the physiology behind it is essential. And it's not nearly as complex as we would think. So, when When I'm teaching this to undergraduates and exercise physiology or graduates and exercise physiology, I write on the board like first day of class, I'm like, you absolutely need to know this equation. It's beautiful, it's simple, and it really defines our existence in human beings. And it's known as the thick equation. The thick equation, I'm going to start with kind of the complex version and then distill it down is...

It's so funny because anyone who's like inside physiology is like, the thick equation, the fake equation. like it's just like blazing across our four heads. Yeah, but it tells you everything you need to know. Everything. Everything you need to know for VOTOMX. Yeah. Yeah. It's n-diastolic volume minus n-sostolic volume times heart rate, times arterial

minus venous oxygen difference, okay? Let's go. Super complex. What are we getting at there? In the most simplistic way, the ability of the body to deliver oxygen to the muscle and then the ability of the muscle to take that oxygen up and use it to produce energy during exercise. Okay. So we started with a really complex version of that equation, really simplistic. Is there some kind of meat in the middle? So let's like look at that

thick equation and the complex things that are in it and understand why they're relevant. All right. So end diastolic volume is a measure of how much blood is making it into the heart, particularly the left ventricle of the heart when it's relaxing. So our heart relaxes and then it pumps all that blood out. And so end diastolic. volume is how much blood is making it into the heart when it's relaxing. Then we have end systolic volume, and that's how much blood is left in the heart after the heart has pumped blood out when the heart pumps. It doesn't pump all the blood out. There's a substantial portion of it remaining. And so the difference between those two, end diastolic volume and systolic volume really

reflects what we refer to as stroke volume. This is huge. This is absolutely key. We need to understand stroke volume. And what that is is, every time the heart beats, how much blood is it pumping out? And that's key. That's going to be the key driver of VO2 max and adaptation to VO2 max. And a beautiful indicator of your overall cardiovascular health. Certainly. And that's the one that can be moved the most. Then heart rate. We all know what heart rate is. It's super easy, super accessible. But again, like you said, is a fantastic indicator of cardiovascular health, fitness health span and it's super easy to measure and that doesn't devalue it right how many times the heart is beating per minute and if we look at our stroke volume how much blood the heart is

getting out every time it beats and then our heart rate which is how many times the heart's beating per minute we can calculate what's known as our cardiac output and that simply put how much blood is our heart pumping out per minute and so we said VO2 max is determined by how much oxygen is getting to the muscle and then how much is being taken up by the muscle. Cardiac output tells us that first half of that equation, how much oxygen is getting to the muscle. The second half arterial minus venous oxygen difference. Our arterial blood is the blood that takes the oxygen and the blood that's leaving the heart, right? So this is really a reflection of how much oxygen is there in the blood that's making its way to the muscle. And then the venous oxygen content, really what it is

is how much oxygen is in the blood leaving the muscle. So the difference between those two represents how much blood is being taken up. As an example, right, if I have a plate of food with 10 skittles on it, let's say, for instance, right, and I give them to my daughter and she eats eight, then we know there's two left. And so 10 minus 2 is 8. That's how much the daughter, or The muscle took up. So arterial minus venous oxygen difference. And so when we think about moving the O2 Max, which is what's so important here, it comes down to, are we more worried about the central factors, heart rate and stroke volume, or are we more

worried about the peripheral factors or the ability of the muscle to take up and use oxygen, which are essential? It's been a longstanding debate. What is the limiter behind VO2 Max? Is it more central or is it more personal? or is it more peripheral. VOTMax discovered over 100 years ago, and what's funny is, exercise physiologists are still debating that today, but the answer is quite clear. And there is a really interesting conversation, a physiologist named Tim Nokes. For years, he's been pitching

this central governor theory, right, that basically says that myocardial ischemia, or the lack of blood flow going to the heart, tells our brain that we're in trouble when we're exercising. And so that's the limiter, but there's just so much data to refute that theory. And we now know almost for certain, and this was also acknowledged back when V-O-2 Max, the concept was coined by A.V. Hill back in the 1920s, that V-O-2 Max is indeed limited centrally. There's a beautiful experiment by a world-renowned physiologist Ben Saltine in 1985, where he measured oxygen consumption, by the skeletal muscle under two different circumstances. And he took subjects and he put them in this single-leg kicking device.

And he had them just kick as hard and fast as they can with one leg. And he measured how much oxygen the muscle could use. He brought them back in a few days later and had them do a full-body V-O-2 max test on a cyclerogometer and also measured how much oxygen the muscle could use. And what he showed really solved this debate. And that's that during the single-leg kicking exercise, the muscle was taking up two to three times the amount of oxygen that it was able to take up when we were doing whole body exercise, which just irrefutably proves that the muscle can

take far more oxygen than is being delivered to it during full body maximal exercise. And so we know for absolute certain that it's centrally limited. When we look at the factors, the physiological factors that determine VO2 max, you know, what is that laundry list? And then if we can just go into, you know, there are some athletes that we can think about, you know, like a Michael Jordan, a Michael Phelps, a Sue Bird, you know, they just have this like engine that you're just like,

they can go forever, it seems. Now did they just come out of the womb? Or is it trained? You know, I would love to kind of understand from a genetic perspective what the research says and then that laundry list of kind of physiological factors. There's a beautiful study known as the Heritage family study, and it was conducted by physiologist Claude Bouchard. And what they did in that study is they recruited 500 adults from 100 families. And the purpose of the study was broad. In addition to

V-O-2 max and cardiovascular health, they were looking at musculoskeletal health, hormonal responses, all to aerobic training. And what they showed was simple, but also very insightful. And they showed that there's 2.5 times more variance in fitness, or V-O-2 max, between than within families. And they concluded that the maximal heritability of VO2 max is around 47%, which I think is pretty cool from the perspective of our listeners and us as exercise physiologists.

No excuses. Right, because it means... We can move this sucker. It's more than half of it can be moved by our lifestyle. Yeah, that's so phenomenal. And so how do we move that? Well, we engage in very structured and purposeful exercise, specifically targeting what we just talked about with a thick equation, and we know is the central

delivery of oxygen to the muscle. And so how do we move those factors? How do we move cardiac output? Well, we know cardiac output is determined by heart rate and stroke volume, and we can't train our heart rate, right? As a matter of fact, we know heart rate is coming down as we get older. So it's all about finding ways to increase stroke volume or the amount of blood our heart is pumping out. This is a good moment to just kind of remind folks that a lot of our ability to kind of tap into this modifiable portion of a VO2 max is setting up conditions that allow you to go at your capacity. And I think that we can't really understate this enough, right? Like if I am showing up in my life chronically under recovered, you know, overfueled, underfueled, underfueled, underslept, I am going to be positioning myself, overtraining potentially.

I'm going to position myself to not actually be able to maximize whatever my VO2 max potential might be. So it's like the foundation of, all right, how do I actually create the conditions that allow me to get to a place where, I am optimizing my potential for V-O-2 Max. And if there's anything you want to comment about that, but just this notion of building capacity through these other rocks are really important. Yeah, no, for sure. It takes everything for us to optimize these metrics, right? And when we're specifically training for something like V02 Max,

it is a high-intensity exercise that we're probably going to want to do. We can talk more about that, but that does require us to set that. proper foundation, right? Right. So, and I think it's, it's worth noting, you know, as we kind of get in specifics of how to train VO2 Max, that you, if your foundation isn't great, anything you try to kind of layer on top of that is going to be more difficult. You're kind of handicapping yourself, right? So your ability to move V02 Max, and the pace at which you move that is kind of contingent on this foundation, right? If this foundation is really has lots of cracks in it, then you can't have a lot of expectation in terms of your ability to move this number.

Yeah, that's a great. That's a great point. And there's a lot of research out there that has noted substantial inter-individual variability in training responses, right? And so there are even plenty of studies, you know, that we do on the performance science team where we see people who are responders and non-responders. And this notion of a non-responder, this is kind of, you know, my bias view, I don't think it exists. I think most likely somewhat there are people who probably don't respond, but I think those people are probably, not getting the right stimulus. And that doesn't necessarily have to be what training they're doing to go in, right? It could be how much they're sleeping or sundry of other variables. Right. And this is, I think, also important to call out that this is not, this foundation is not just reserved for the top athletes in the world, right? I mean, this is for everyone, right? Like, creating this found. If your goal is to increase your health span, which we know VOTU max is an excellent proxy that helps us understand your potential for longevity. This foundation needs to be tended to.

Just remembering that, you know, how we sleep, the consistency and the timing and the quality of our sleep that is going to lay an enormous foundation for our ability to kind of train these systems in a way that really optimizes our potential. Let's look at VOTOMax from the lens of performance and let's look at it from the lens of longevity, which I don't think are orthogonal, but I think people in their minds think of them as such. And certainly there's really extreme versions of training that actually probably don't necessarily ladder up to longevity, right? I mean, there's a lot of really extreme things that have to go into being the top cyclist in the world, for example, that I think

we could argue might not actually help with longevity in some way, right? Like potentially. So maybe just talk about the difference between performance and health. Yeah, I think that's one of the coolest things about V-O-2 Max I was thinking about and preparing for this episode is it is irrefutably the single best predictor of performance. If I'm trying to predict whether someone's going to win a gold medal, V-O-2 Max is going to predict it better than almost anything across sports, right? But it's also perhaps the single best predictor of whether or not someone needs a heart transplant or may not live a super long time. And how cool is it that we can have this one single metric that could predict outcomes across the health spectrum from in the greatest of athletes

to some of the most unhealthy individuals. That's just, it's kind of mind-blown to me. It's pretty cool. It's very cool. What's up, folks? If you are enjoying this podcast or if you care about health, performance, fitness, you may really enjoy getting a whoop. That's right. You can check out whoop at whoop.com. It measures everything around sleep, recovery, strain. And you can now sign up for free for 30 days. So you'll literally get the high performance wearable in the mail for free. You get to try it for 30 days, see whether you want to be a member. And that is just at whoop.com.

Back to the guests. Maybe just talk about the values. Let's do women first. And then we'll do men in age brackets. So I think if we can just kind of move through 20 to 30, 30 to 40, and then what those values should look like, anything else you need to add that. creates enough context for folks who have never heard about these numbers before. So just to kind of provide a bit more substance to my previous comment about it being such a

robust predictor of longevity across the health span, and this kind of sets the table, I think, for providing some of those values. It is, this has been known for for some time. World renowned exercise physiologist Steve Blair back in the 1980s published a paper when he was at the Institute for Aerobic Research in Dallas, 15,000 people showing and concluding, it was a longitudinal study about 10 years at higher levels of fitness, and they concluded this in the conclusion of the abstract of the paper, delay mortality, point blank due to lower rates of cardiovascular disease and cancer. And so what exactly does this look like? In 2002, Jonathan Myers at Stanford published a groundbreaking paper in the New England

Journal of Medicine. Six thousand men, a thousand of them died. They concluded that, and this is pretty neat, in my opinion. A one-met increase in your V-O-2 max, and so a metabolic equivalent is equal to 3.5 milliliters per kilogram per minute, as far as relative V-O-2 max goes, is associated with a 12% increase in survival. Furthermore, they broke their participants... Three METs, 3.5. And we're talking training adaptations, right? Three or four months of training, we're seeing increases on average of 20 to 30%. And so if you have someone who has a VO2 max of 35, which would probably be the average for maybe a 40-year-old female,

35 milliliters per kilogram per minute, they do VO2 max focused aerobic training for four months. Their VO2 max increases by 20 or 30%. They've possibly reduced their risk of mortality by over a third. And what's really cool about it, and this has been repeatedly shown, Jonathan Myers published this paper in 2002, but then he most recently published a paper in 2022 that replicated these findings and what I'm about to say. And this most recent paper, just for context, nearly a million individuals, and it was a prospective study, so longitudinal study. They broke their participants, these are almost a million people, down into quintiles, basically 20% bottom, bottom, 20% next, et cetera, et cetera. The people in the highest fitness quintile were 4.5 times

less likely to die than the individuals in the lowest fitness quintile, which is great if you have a high degree of fitness and not so good if you have this low degree of fitness. What does this look like? The high degree of fitness uniformly across almost all of these studies is right around 14 to 15 METs. So to put that in perspective, we're right around a VO2 of 45 to 50 milliliters per kilogram per minute. If you're over that, you are robustly protected from your health. Bulletproof. You get pretty much, right?

Yeah, it's fantastic. Now, I'm not saying that you should necessarily stop there. We want to see you. We know that there's a dose response relation between increasing VO2 max and health span and mortality, right? But if you're in that quintile, you can be feeling very, very good about it. The really cool thing, though, is that the biggest benefit of increasing your fitness was not making it into the top, but it was going from those who were in the least fit group to slightly less fit. Just for an example, the people in the least fit group

were 4.5 times more likely than to die than those in the top, but the second least fit group was only two times more. So exercise is valuable. It's great to chase the highest level of fitness, but going from doing nothing to doing just a little bit, just going for a walk a few times a week, that's where you're going to get the greatest benefit. And I think that's a very powerful message for people who are intimidated about like 300 minutes per week of exercise. That stinks if you're not doing anything. And you may just say, well, the heck with it, I'm not going to get it. But you don't need to do that. All you need to do is go from doing nothing to doing just a little, little bit. And you are robustly going to increase your odds of living a longer,

healthier life. And that's what's so cool about this. I love it. That is such a compelling framing for our listeners. So thank you. And it's been repeatedly shown in numerous studies. Something is better than nothing all the time. The benefits of something are much greater than they are of doing a ton. Right. Love it. So Greg, I think that's a really good framing for kind of the health side. Now let's talk a little bit about what does performance actually look like. So we know that quite a small dose of VO2 max type training over the course of a week for months at a time can move you from that bottom quartile to the next quartile, which is massive. And you just describe the fact that that can lead to years on your life, right? Adding years onto your life

on your health span. Let's talk about just the performance side of things. So for folk who are competing at really high levels, like what does VO2 max mean for them? Again, both for performance and health, there really is no upper limit that we want to stop at. It's like, not like if we see 60, it's like, okay, this is like a good place to stop. It's like the higher we can get it, generally the better for both performance and health. You know, when we look at the fittest individuals in the world, right? And they're always kind of like fun examples of things that are not realistic for 99.9% of us, but it does provide us, I think, a unique way of understanding. Yeah. The extremes are important for us to understand how do we kind of get

into that middle ground where is kind of the sweet spot for most folks. Yeah. And I think appreciating the function of it kind of allows us to back into the training of it. So I want to start with just kind of a simple question that I would always ask my students and I think a lot of people they know but they don't understand why. And that's why is it that individuals who are more fit have a lower. And the answer is extremely simple. And it goes back to that thick equation we are talking about. So when we compare people who are the fittest in the world to even some of the least fit in the world. The truth is the amount of oxygen they need when they're sitting around at rest is relatively comparable. It happens to be

that that can be delivered through about five liters of blood pumped around their body per minute, which super cool is about how many liters of blood we have. So it's just kind of neat to think like when we're at rest, our body circulates our blood about once per minute. It's kind of like a fascinating miracle you know yeah when you zoom out yeah this is even possible it's just so tightly orchestrated you know it's just it's a miracle but our body's ability to circulate that five liters of blood once per minute looks very very different in someone who is not trained versus trained and so let's just think about someone who's you know maybe moderately trained uh average individual healthy has a resting heart rate of about 70 beats per minute let's just say you go to the doctor 70

beats per minute, very average, okay? So if your heart's beating 70 times in a minute and it needs to circulate five liters of blood, we can do the math, and we know that it's pumping out about 70 milliliters of blood per beat, which is about three ounces of blood per beat. Why is it then that someone who is more fit, their heart beats slowly? Well, we know cardiac output or the amount of blood going around still is five liters, and so if heart rate's coming down, that can only be due to one thing and that's stroke volume going up. And so let's say we have someone who's quite fit and they have a resting heart rate of 50 beats per minute. We know that is because their heart is pumping out far more blood. They're pumping out about 100 milliliters of blood per beat, which is pretty

cool. It's almost 30% more than the unfit individual. I think it's really interesting in our data that the fitter you are, the better you sleep, the more efficiently you sleep. So it's like this incredible virtuous cycle. You know, people are like, I want to sleep better. First, fix your circadian rhythms, but that aside, get fit. Fitness is going to drive. You know, because when you're creating conditions during sleep that actually allow for proper restoration and recovery, which allows you to go out the next day and have capacity to work.

Yeah. And we see that not only with just sleep duration, right? Yeah. We see the people who are fitter are getting more bang for their buck with their sleep. They're sleeping more efficiently. They're sleeping. And they're actually spending less on in bed. Right.

That's the thing to your duration point, you know, which is like such an exciting revelation, really. It's super cool. It's so damn cool. Yeah. No, I love that. I love that. So at the highest end of the spectrum, right,

we're talking about like elite performance. Miguel Enderan professional cyclist was recorded as having a resting heart rate of 28 beats per minute at one point in time. So you do the reverse math on that. He had a stroke volume of about 160. 60 milliliters per beat during rest. It is more than twice, right? What a normal individual has.

So that's pretty cool to think about. So he's basically breathing three times in a minute? Did I do that bathroom? His heart, yeah, his heart's beating, you know, 30 beats per minute. So beating like once every, yeah, every two seconds his heart's beating. And he's taking in, so in terms of like his ability, he would only have to take three breasts per minute. Yeah, I think that's right.

It's pretty cool. Yeah, it's pretty cool. Very cool. But then let's think about it during exercise, right? So that untrained person who their heart at rest or moderately trained 70 beats per minute, 70 milliliters per beat, what's cool is during maximal exercise, let's say they can achieve a heart rate of 200 beats per minute, which is high, but maybe we're seeing it in like a 20-year-old. Their heart during maximal exercise can pump as much blood, their stroke volume, as someone who's really fit is pumping at rest. So that really fit person at rest, their heart is pumping as much blood as the less trained person can pump during maximum exercise. And so as a result of that, they're pumping out about 20 liters, 200 beats per minute times about 100 milliliters per beat, about 20 liters of blood per minute.

Right. On the very end of the fitness spectrum, fittest athletes ever, right, we have maybe they're still around 190 or 200 beats per minute. But their hearts are pumping out 200 to 200. 120 milliliters of blood per beat. So they're achieving cardiac outputs of like 40 liters, which is like almost unthinkable. And another really cool way to think about that, right, is if our heart is beating 200 times

or even 180 times for a minute, we know it's beating out. It's beating three times every second, which to think about your heart beating three times every second is wild enough in and of itself. And when it does that, it's pumping out almost eight ounces of blood. So our heart is essentially ejecting 24 ounce water bottle every second crazy to think about right and just like to be able appreciate that from like a physiology

perspective and so as a result they're able to consume seven or seven and a half liters per minute of oxygen and the highest VO2 max ever recorded was actually recorded not that long ago and it was a very unique story it was a a story about a he started off as a skier and then three years of highly bike specific training. His VO2 max went from mid to high 70s to 96.7 milliliters per kilogram per minute. So far, no human that we've ever been able to see has hit 100. It probably will happen here at some point in time. But 96.7 and a male and Paula Radcliffe as a female was recorded in the 70s. Unique about both these is they were both relatively young when this happened. So we're talking like 17 to 18 years of age. So the good news is we don't have to go chasing

the highest VOT2 max forever going to get because we know starts to decline. as we get older. So VO2 Max is going to decline. We talked about just giving our readers some referent values just so they can kind of ground themselves in. So we see the very top end athletes, you know, men as high as 97 at the very top end, but probably really elite athletes. On average, men are probably in the 80s. Women are probably in the 70s. And then generally speaking, those folks are going to be in their 20s-ish. And then when we get into kind of 30 to 40-year range, we can expect really elite athletes to be in that kind of 60 to probably 50, high-end 50 range for women. And then we kind of go down basically as we age.

Yeah. And there have been many beautiful studies that have looked at this. V-O-2 Max begins to decline somewhere between 25 to 30 years of age, and it generally declines about 10% per decade. But we can slow that down. And we can slow that down a lot. And let's talk about how to do that. Yeah. Yeah. And there's beautiful studies done by John Holley in particular. who's done a lot of this work, Andy Coggin, et cetera, and they've shown that in people who are able to sustain a high level of activity across the lifespan, that 10% per decade or declining 1% per year can be slowed down to maybe 1 to 2% per decade. Yeah, I mean, that's...

So how do we do that? Yeah, how do we do that? So we hear a lot about metabolic flexibility. Maybe just talk about, because, you know, that's a very big buzzword, you know, as it relates to VO2 max. I think people hear metabolic flexibility in VOTOMax kind of in the same conversation. So maybe just break down what that means, why it matters, how it might be different for men and women, and how does that inform our training?

Metabolic flexibility, we're specifically referring to substrate utilization. We talked about how VO2 Max is really our ability to produce energy or ATP using oxygen, but to produce that energy or ATP, right, we're needing to use fuel sources, be it fat versus carbohydrate. And so when we talk about metabolic flexibility, we're really referring to, from my understanding, our body's ability to transition between those fuel sources and to rely on whatever fuel source is optimal for the given intensity or exercise duration that we're trying to participate in.

The higher of you to max, the better we are switching between these fuels. Certainly, yeah. The training associated with both. And a lot of that has to do with our mitochondrial health, right? If you kind of back up into the physiology, the fitter we are, the healthier mitochondria. So you can see that relationship is really tight. So when we talk about, you know, increasing our fitness, we're increasing our metabolic flexibility, and we're improving our mitochondrial health in the process. Yeah. That's part of a diverse training program. Exactly, yeah. So when we think about VO2 max training, so our members are going to have this metric at their disposal now. You have just given them every reason of the world to improve VO2 Max. How do they go

about it? And if again, we talked in the beginning of just backing into, okay, you know what, I'm a CrossFit athlete, that's all I do. How do we fit this in to our day? And how do people create that framework? And then what actually do they do? When we think about training, often I think we like to make it far more complex than it actually is. Steve Magnus just posted something on Twitter that I really loved. And it talked about the specific, like, training routines of, like, the most elite athletes. And it's like, they wake up. So boring. They have coffee. They take a poop and then they go for a run. And then we have these, like, really, you know, fitness influencers. And it's like, you know, they wake up from sleeping on their wooden beds. And they have some bulletproof

coffee with butter in it. And then spin around three times. Duck their face in cold water. with a snorkel and put the wrong shoes on the wrong feet. It's not complex, right? And so if we're thinking about VO2 max, again, understanding the physiology, someone can hold a VO2 max effort depending on their level of fitness for one to 10 minutes. So how do we increase it? As a principle in training known as the said principle, which is specific adaptations to impose demands. If we are trying to improve our body's ability to sustain an effort lasts one to 10 minutes, we need to do maximum efforts that last one to ten minutes in duration. That's what's been shown in the literature.

Very common protocols for this. Papers, again, from Andy Coggin and John Holliz, Seminole training studies, four to six rounds, five minutes essentially as hard as someone can go. They're doing 100 to 120 percent of their functional threshold power on a bike with two and a half minutes of rest. But essentially, each of those five-minute intervals needs to be as hard as you can sustain with two and a half minutes of rest. other things. Four by four minutes with four minutes of rest is one that's tremendously popular. And it's exactly accurate. I do that every 10 days. There you go. Right. There you go. I think it's important note that if people are just starting out on this journey, like you're

going to have to take time to figure out your sweet spot. Because when you first start going, you'll maybe go kind of hard for 30 seconds. You'd be like, oh my God, I started too fast. Like it's a level that you can sustain for four minutes or even start. one minute, you know, at, like, as hard a pace as you can go for that minute. Yeah, this isn't the 30 second all out where by the end you're walking. No, no, exactly. It's ideally sustained effort. Yeah, it's sustained effort.

So, you know, you're trying to get into that upper threshold of 85% to 95%, but just know it's going to take time to be able to get to a place where you're staining that threshold between four to 10 minutes, right? Like, you know, as you get fitter, the longer you're going to be able to sustain that upper threshold. but that takes time to be really clear. So to start, folks will just want to go, you know, a minute, I think is a good place to start. You might be power walking for a minute.

If you have been really sedentary, it might be a power walk for a minute. Or you're on a steep treadmill. Or you're on a steep treadmill, right? Exactly. Or I always go walking or running, but you can bike. There's lots of different modes. You can be in an erg, a ski bike, a ski, a cross-country ski. What are those called?

The Nordic track. Nordic trier, yeah, yeah. Nordic skier, yeah. So there's lots of different ways that you can get after it, but just know that it's going to take some time to kind of get to the place that you're describing. Yeah, and we don't need to do this every day. In fact, please don't.

Once, twice a week is plenty. 20% of your total training time or less even, yeah. Should be spent in these zones. People who are not accustomed to this, it's an extreme load. Like going all out is not necessarily a fun time and it's not something that we should all be doing all the time. right so again building up into it starting once a week with maybe one or two rounds of it if we're not accustomed to these types of things are really big there's another just really cool paper that i want to talk about this published in 2020 in the scandinavian journal of sports medicine by brent ronstadt and carson lundbee from norway and they compared kind of this seminal for by five minute with two and a half minutes of recovery that from john hollazy and and and they compared it to these kind of tabata style and

intervals that have kind of picked up in popularity. And in particular, they had folks do three, nine-and-a-half-minute rounds of 30 seconds. We want to go all out, go ahead. 30 seconds as hard as you can go with 15 seconds of rest, and you want the quickest 15 seconds of your life, try this workout, because time never passes more quickly than when you're doing 15 seconds rest between 30-second all-out intervals. And this is one I use for all my athletes. It's kind of fun.

Yeah. But yeah, so it's three rounds of that. Three rounds of 13 by 30 seconds all out with 15 seconds of rest. And this is really cool. The cyclists they did this in, Kristen, had a V-O-2 max of 74 on average coming in. So these people were very, very fit. Three weeks of this boosted their V-O-2 max 5%. So you're starting with some of the fittest people on Earth and boosting V-O-2 max 5%.

And it's novelty. So that's another thing that I think is really, really, really important when we're thinking about doing training. Consistency, in the words of one of my old soccer coach, right, is maybe what pays the bills. But novelty also matters. Right. Right. A new stimulus is going to accelerate adaptation. Exactly. And so thinking about, it's not bad to think about fun ways to do these types of things,

whether it be training modes or doing it. Yeah. I mean, I do about a once a week, you know, where it's 20 on, 15 off or 30 on, you know, 20 off, you know, any of that, that type of ratio. And you really, I think to train that, you just think, get a really good warm up in. Because if you don't, your first couple reps are going to be horrible. You're, you know, I see my data when I don't warm up. Like, I just can't get my heart rate up as high. So they're just not quality reps.

So get yourself good, you know, get your heart rate up in your warm up. So you're not sandbagging your first rep because you really want to think about when you're doing the Tabata. It's like you want to think, all right, I can do, I can do 115 meters in 20 seconds, right? So not quite, but that's aspirational. Yeah. Let's just say I can do that. And so that first rep, you want to get to kind of that 115 meters. And then your second rep, you want to get 150 meters.

So as soon as you get to a place where in that 30-second period, you can no longer achieve that distance, you want to stop, right? And then maybe if you can just talk about quality of reps as it relates to VO2 max and why that's really important. This is a mistake that I think people who are more new to exercise. I'm sure you as a coach see this all the time. And a lot of the athletes I'll work with, I think some of the biggest improvements they'll make is when they go easier during the easy portions of these rests.

So, for instance, in the paper from Ronstad and Loondby, they're doing, again, three rounds of 13, 30 seconds all out, 15 seconds rest. In between those rounds, there's like two and a half to three minutes of rest. And like when I'm telling people to pedal on a bike, it's like we're talking about like 20 watts. This has to be super, super, like easier than that of a walk. Like if you were putting out this energy on your feet, you'd be falling over. It'd be so easy. Right. Because if you are not taking sufficient, and this is huge, if you are not taking sufficient rest,

to where when you are doing those sets of work, you are able to maximally tax the system and you are working at a V-O-2-Max level, then you're not going to improve V-O-2 Max. Exactly. No one cares how easy you're going during the rest. If you're doing three-by-mile for run, you know, hallmark run workout.

And this is why hit is so ineffective. Right. In terms of it's not training V-O-Max to be super clear. And if you're going moderately hard during the rest, you're not going hard at all. You might as well just go for a continuous run. Exactly. That's physiologically the exact same.

Right. There's no heroes made during the rest sets, right? Well, that's amazing. So if we think about our training over the course of a week and any kind of movement, any kind of programming, honestly, as long as you're moving, is going to be better than nothing. There's no question about it. But there is a way to train, I think, efficiently if we're looking at purely from a health span perspective, you know, which we measure now in the most elegant way possible, VOTU max is one of those, you know,

kind of inputs. And you'll see it's the most important input. If you're looking at what's changing your health stand, it's like you maximize your V-O-2 max, you're all of a sudden six or seven years younger. Right. So when we talk about cardiorespiratory fitness and just cardiovascular fitness, like we're talking about two energy systems, of course, the aerobic and anaerobic. The VO-2 max is taxing our anaerobic system, which is going to be these upper thresholds that

we're talking about. And we do that 20% of the time, of course, a week. So twice per week. at the very most for a relatively trained human. It could be one time a week for a person who's not as trained and you're building up to two times a week. But basically two times a week where you're really getting out of breath

for a sustained period of time, resting completely in between repetitions, and you go as many rounds as you can sustain with quality. So that's going to be very different for you than it is for me. And then the other 80% we're doing kind of base training, zone two type of training where it's a low effort we do the talk test we've done lots of podcasts paul larsen was one of our most popular podcasts or we talked about zone two so you know refer to that if you need to understand zone two and then understanding we need to be lifting weights right and

that's another input to our health span is is the amount of time you're spending um resistance training right so that's a really important part of your programming as well so not to be overwhelmed um But if you were to kind of have to say, all right, for a person who's starting out, what is the taxonomy across these energy systems? Where should they start if they want to really move the needle in terms of health span? Yeah. Start going from doing nothing to doing something. And that's whatever will get you moving. People will often ask, you know, not doing anything. Like I'm trying to get into exercise. Should I do lifting or should I do walking? And you can say yes. But the truth is it's whichever you're going to consistently do. Right? So going from doing nothing to doing something. Then, you know, in an ideal world, you have all the time in world. What are you doing? Lift weights twice a week, if you can. If you're not lifting weights twice a week, then you're not maximizing your gains. So lift weights twice a week. And that matters whether or not you're trying to win the CrossFit games, but it also matters if you're trying to bend down or get in the car as you're getting older. It matters. It matters for running. It matters for cycling. There was a really neat study I saw published in the journal Strength and Conditioning where they took, again, elite level cyclists who had very high five-minute power outputs, maybe they were around 350 watts, and they had them do strength training. And just that strength training alone significantly boosted

their five-minute power on the bike. So it is improving, and there's a lot of relations we see with this. With running, we know that lifting can speculatively maybe improve running economy, which is another huge factor that's going to ultimately relate to performance. So lift weights twice a week if you can, right? For aerobic exercise, it's been clearly outlined that we should try to achieve at least 150 minutes of activity. If all you're going to do is low intensity, well, then just do that. Now, if you can add in one high intensity session, do it. If you can add in two and one of the beauties of using whoop, right, is when you're adding these in, you can look at your recoveries and look at your heart rate and your heart rate variability the next day. And it'll tell

you if you're adding in too much too soon, right? If you're continually in the red, then doing another V-O-2 Mac style workout that day is probably not the ticket. And just as a reminder, being in the red is a signal that your body is not responding and adapting to the load that you're putting on it. So it could be, it might be your training, but it could also just be other life load that is contributing, right? It's not just your training that recovery is picking up on. It's really all the inputs, right? It's how you're eating, how you're hydrating, and all of those things, you know, work together to position you to be ready the next day.

But, you know, if you're in the red, that it means to take inventory across these big rocks that we know move recovery and just figure out where you might be going wrong. And it's not a bad thing either, right? If I'm really trying to train for something, if I'm working with an athlete and I give them a high-intensity workout and they're not in the red the next day, it's like, well, maybe they can do a little more, right? Or low, yellow. There should be a suppression, right, in your heart rate variability.

It should be increases in resting hearty. That means that your body heard, you put on a stimulus. And if you give it time to rest, it's going to adapt. And that adaptation will lead to growth if you give yourself the right amount of time to recover. Dr. Kisicki, this was super fun. Your knowledge just continues to impress me and just really grateful for all the insight you're able to transfer today. I think it's going to be hugely beneficial.

So thank you. Yeah, always a pleasure to get on and particularly to talk about one of my favorite topics. Yeah, I can tell that you're so passionate about it. And thank you again. Thank you. If you enjoyed this episode of the WOOP podcast, please leave a rating or review. Check us out on social at WOOP at Will Ahmed. If you have a question to us answered on the podcast, email us, podcast at Woop.com.

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As always, stay healthy and stay in the green.