WHOOP Podcast - The Science of Human Performance: What is Strain?

Episode Date: June 24, 2026

Welcome to the Science of Human Performance Series where we are breaking down the key metric for you to improve your fitness. This week, we’re unpacking Strain with WHOOP Global Head of Human Performance, Principal Scientist Dr. Kristen Holmes and WHOOP Staff Research Scientist Dr. Greg Grosicki. Together, Dr. Holmes and Dr. Grosicki explore how both cardiovascular and musculoskeletal load are taken into account when measuring a member’s daily strain to help balance training, recovery, and build long-term fitness. The conversation explains the influence of WHOOP Strain on overall fitness goals, from improving fitness to supporting weight management, and increasing VO₂ max. This episode will give practical guidance on your training routine, helping you build the habits necessary for performance, healthspan, and longevity. (00:00) Looking To Gain Fitness? WHOOP Strain Can Help(01:25) What is Strain?(02:07) How Does WHOOP Measure Strain?(03:21) What Is The Neuromuscular System – Why Does It Matter For Strain? (03:57) How Does WHOOP Measure Musculoskeletal Load?(08:09) Creating Impactful Strain Recommendations: WHOOP Coach(11:16) Exclusive Offer For WHOOP Podcast Listeners(11:50) Why Is Strain Measured on a 21-Point Scale?(16:37) The Power of Consistency: Improving Fitness By Following Strain Coach(23:21) Refer A Friend: Get 2 Months Free!(23:56) Is Strain The Biggest Lever For Improving Cardio Health? (24:57) How To Improve Strain (Habits For Busy Individuals)(27:03) Focussing on Heart Rate Zones(29:32) What Does VO2 Max Tell About Strain?(32:21) Building A Fitness Routine: Is Changing Strain Activities More Effective?(39:06) Exclusive WHOOP Advanced Labs Offer(39:40) Can You Still See Fitness Gains With High Strain & Low Recovery? (41:01) Greg & Kristen’s Go-To Strain Activities For Fitness(44:50) Thanks For Listening: New Member Offer & WHOOP Apparel & Accessories DiscountSupport the showFollow WHOOP:Sign up for WHOOP Advanced LabsTrial WHOOP for Freewww.whoop.comInstagramTikTokYouTubeXFacebookLinkedInFollow Will Ahmed:InstagramXLinkedInFollow Kristen Holmes:InstagramLinkedInFollow Emily Capodilupo:LinkedIn 

Variety is a spice of life, but consistency pays the bills. One of the beautiful things about Wu being this personalized coach is we provide members with strain recommendations every single day. Very simply based on what your current sleep and recovery look like. If you have a better night's sleep and a higher recovery, we recommend that you do more strain. We have science backing up that if you meet those strain recommendations, there's a facious outcome. This is such an exciting finding.

We found that our strain coach, when folks listen to it and to your point meet their daily strain target, they actually get fitter. The strain targets we're giving you are based on your capacity to take on that strain. So we're not going to tell you to meet a strain target that you're not capable of meeting. Not just the load of how you're responding. Exactly. So I think for folks who are coming on to our system who maybe haven't played a lot of sports, it just wasn't part of their life, right?

They don't maybe have some of this intuitive sense of like when to push, when to hold back. I don't even argue some elite athletes don't necessarily have that real good sense of how to balance that, right? We're really able to guide our members around how much strain to optimally put on your body, which will allow you to get fitter, but without compromising your ability to show up tomorrow. And we know in order to get fitter, consistency matters. All right, Dr. Grega Sicki, welcome. Dr. Kristen Holmes, pleasure to be back. I'm super excited to dig into strain. Really, the goal of today's episode is to help our listeners understand exactly what this metric is, why it matters, and how to think about it in the context of their life.

At a really high level, of course, strain is a measure of load. So not just your training load, but just your life load, daily load. So the activity, the non-activity load that you're putting on your body. So it's this really beautiful 24-7 picture of how you're building load across the day. So as just a primer, maybe talk a little bit about how we measure strain and why that matters. For sure. Perfectly said. I think one of the things that's unique about WOOP is that it's delivering these 24-7 health insights, just as you said. And with strain, we're measuring, starting off, first and foremost, cardiovascular load.

And so we're measuring that in a way that's personalized. We're looking at what your heart rate is throughout the day every second relative to whatever your baselines are. What is your resting? What is your maximum? And then we're telling you how hard your cardiovascular system is working. And that could be within an activity if I'm going for a run. but it could also be if I'm just doing regular things of daily living, if I'm going to the grocery

store, or if I'm out in the garden for a couple hours, or if I'm coaching my daughter's soccer practice, and it's providing this nice integrated metric of your cardiovascular load. One of the things that's really, really exciting is what we recently rolled out with with strain. And we know that strain has a lot to do with how hard your cardiovascular system is working during the day, 24-7, but also there's your neuromuscular system. And so would you like to talk about what we just recently wrote out there? Yeah, that'd be great. So I think, so just so our listeners understand, strain takes into account both cardiovascular

load as well as musculoskeletal load, which is what I think we should talk about now. So it's not just a measure of heart rate activity as it relates to your walking or running or those type of activities, but it incorporates when you're lifting weights. So resistance training and muscle skeletal load. So yeah, talk about how we've been able to achieve that because that's, I think, quite a feat. Yeah, it's super, it's incredible. And I think it's super unique to whoop and something that we're able to uniquely provide members. And it came from members giving us feedback and us realizing that just quantifying cardiovascular load isn't adequately educating and informing members as to how hard they worked in any given day.

Right. If, for instance, I don't go on a run one day and opt to do resistance training for an hour or an hour and a half, my cardiovascular system isn't necessarily working as hard, but that doesn't mean my body isn't still accumulating a pretty substantial load and possibly a greater load. And I could go to the gym and lift really heavy for an hour and a half and feel incredibly sore the next day. And that's not going to be captured by musculoskeletal strain. So the wonderful machine learning research team, partnering with product and marketing and other team and our performance science and health outcomes team at WOOP have been working on this for years. And so what we did is we

use the IMU initial motion units technology in WOOP with the gyroscope and the accelerometer to quantify the amount of weight lifted in a given training session. Now, when some people do strength training on whoop, they take full advantage of the product and use strength trainer, where they're telling whoop the weight they're lifting. So starting out with maybe three sets of 10 knee extensions and doing some biceps curls and some bench breasts, et cetera. And 80 pounds. Exactly. And so we're able to, from all of those workouts, again, probably billions of workouts in our database, just kind of get an understanding of what that activity looks like from the perspective of whoop data. And then we're actually able to use AI and machine learning to figure up to quantify approximately or estimate what that load looks like even if someone doesn't put their workout into strength trainer.

And so members now see that in their data that when they do a weightlifting activity, they get musculoskeletal credit. And it even gives you a breakdown of that activity. What was the cardiovascular load of it? Right. And then what was the neuromuscular load? So if I go into the gym yesterday is a really good example, I did not do any running. I just lifted weights. And I didn't put it into, I didn't start a strength trainer activity.

So if so folks listening, if you go into your app, there's a little plus sign. You can add an activity. You can start strength trainer and would recommend starting strength trainer and kind of going in just so you can capture, I think, probably a more accurate estimation of what's actually happening inside that strength training workout. But for me, it passively detected. It knew that I was strength training. It was able to give an approximation of how hard I worked during that strength training session. So now I'm kind of getting credit for it, as you would say. So now it's what used to be just strain, you know, and its previous state was more of just, you know, capturing cardiovascular effort.

Now we're still capturing the cardiovascular effort, but now we're also capturing that musculoskeletal load. and giving you a really good picture of this kind of total strain, give you credit for all the work that you're putting in inside the gym and running and whatnot. Yeah, and that's incredibly valuable from the perspective of being this personalized health and fitness coach. If we aren't picking up on that musculoskeletal load that you're doing in a given day, then we may not be able to give insight as to why your metrics look the way they do a day from now or three days from now or five days from now.

And we may be improperly quantifying the training experience that you've had and then not advising you appropriately. Right. And so I think bringing that to our members, massive kudos to the machine learning research team for getting that done. And I think that's something that members will really appreciate from WOOP. One thing, Kristen, I think we probably should maybe take a step back, but I think really important to outline is what are, what do the strain numbers on WOOP look like? Yeah, even maybe before talking about how we come up with your activity strain and daily activity kind of number. Because you mentioned that. I think there's a really important point to kind of double click on is that if now we're able to give a really holistic picture of the load across the day.

And that impacts maybe our sleep need recommendation, like how much time you might needing to spend in bed. It's not an egregious amount, but it's, you know, maybe a few more minutes, you know, that you need to spend in bed in order to fully restore for tomorrow. And now that we're able to kind of take into account the neuromuscal, the musculoskeletal load as well as the cardiovascular output, now all of a sudden we're able to recommend, give more complete recommendations as to enable to kind of quantify more holistically how ready you are tomorrow. Right. And that's where we were a little just efficient, you know, and I think to your earlier point, like not able to give, I think, the most, the highest fidelity recommendation around recovery, right?

So kind of strain and recovery, recovery is, you know, your capacity to take on external stress, external load, that you get that score when you wake up in the morning. And that will be part of a separate episode. But I think important to recognize kind of how strain and recovery work together. And it's this balance between your strain, how much load you're putting on your body, and how you're adapting from that load is really the source of insight that allows you to proactively manage your training and your just life load in ways that ensure you're adapting in a functional way, right? Which is kind of what we're after here.

And I think it's super timely that we've integrated the musculoskeletal load. The more science-based members that we have listening are probably very aware that the American College of Sports Medicine just recently launched the release of their updated guidelines and recommendations for strength training, which make it abundantly clear that strength training is an integral component of optimizing health and reducing mortality risk. And so us releasing musculoskeletal load and then maybe a couple weeks later, the American College of Sports Medicine, which musculoskeletal load specifically was designed to consider the load that strength training is putting on your body. And then the American College of Sports Medicine rolling out with

these new guidelines and recommendations for the incorporation of strength training was timely and not a coincidence that that happens, right? So we're moving on the cutting edge of this stuff. Great point. And speaking of being on the cutting edge, there's no other kind of wearable on the planet that is pulling in these type of data and providing the kind of insight around recovery that we are, right, in terms of how you're building strain and then how you need to, you know, how you need to plan your rest, you know, in order to adapt in a way that is

functional over time. Yeah. To your point, it isn't a coincidence, you know, that we're kind of following the science here. And I love how we are as a company leading into strength training and just working to get that right for our members. It's amazing. 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 to see whether you want to be a member. And that is just at whoop.com. Back to the guests. So strain, what do the numbers look like? Do you want to start by? Yeah. So, you know, it's loosely based on the Borg scale of perceived exertion.

I think it's six to to 20. Based on how hard you think you're working, you can kind of classify that as light, moderate, heavy, and that usually maps, that perceived exertion usually maps really with reality quite well. So I think the inspiration of this scale, we go to 21, this inspiration of scale really came from this Borg philosophy around exertion. And so that was kind of the inspiration, you know, behind this scale. And for those that don't know whenever I would teach exercise science, I would ask people, you know, Gunner Borg came up with the rating a perceived exertion scale. And it goes from six to 20. And I would all ask my students, do you guys know why this is? No one would know. I think it's kind of interesting. And it makes

total sense is if you multiply that by 10, you're getting the approximate heart rate of the individual when they're doing it. Right. So if I'm doing something like 60 and if I'm doing maximal. But we will have to give members just that extra strata to achieve for. The aspirational. This comes from Will Ahmed. Just being like, we're going to go 21. Yeah. The heart rate can get to 210. And so we see that in the data. Sure can. And so we have our modified whoop strain scale, which can start all the way down at zero

and go all the way up to 21. Or to 20.9. Did we confirm that with M? There may be some 21s out there. Maybe members could leave comments if you've ever achieved a 21 screen. I've gotten 20.7 once and I was not feeling very well. Not great. Next day.

Our Boston marathon runners, we just had people run the Boston Marathon. I believe average strain during the Boston Marathon. was about 20.3. So I think if you're a member and you've achieved a strain over 20 at any particular time, that's something you can be proud of. And one thing that's super important, I think that often can be kind of confusing to new members is that strain is not a linear scale. And everyone has probably seen this app. And they're like, this is like, you know, I'm not really understanding this. Yeah. If you do two different activities, just to clarify, if you do two different activities and they both have a strain of 10, then intuitively, you

may think that you would have a cumulative strain of 20. And that's not the way it works. And we did this more from a scientific-based perspective. And strain instead follows this logarithmic scale. And members will probably see this in the data, that getting out of bed and going and making your cup of coffee and then maybe taking the dog for a walk, you're already at a strain of four or five. Yeah. Exactly. Pretty easy to achieve a strain of four or five. But then from there, every additional strain unit you're adding on top of that takes a little bit more effort. So instead, if you have two activities in your woup device in a day and you have strains of 10, my guess would be that your absolute strain for the day might be something more closer to 12 or 13. And maybe just

explain the physiological underpinnings of that decision, right? Because it has, it definitely follows some very clear logic. Yeah, I think it's basically based on the fact that if you do you know, one particular activity, it's creating whatever physiological distress to the body, and that they aren't necessarily cumulative, that instead there's, again, they follow more of this logarithmic pattern that taxing the body or inducing this physiological demand on the nervous system or the cardiovascular system or the neuromuscular system, it takes a greater amount of effort to perturb or disrupt our physiological systems if we've already created a certain magnitude of stress. And so I think it probably follows those principles. Yeah. There's a ceiling

on how much you can perturb the system before it just basically shuts down and prevents you from continuing to stress the system. Exactly. Exactly. And so one of the beautiful things about being this personalized coach is we provide members with strain recommendations every single day. Very simply based on what your current sleep and recovery look like. And so if you have a better night's sleep and a higher recovery, we recommend that you do more strain. Very easy to see in the app, you open it, you have your sleep, your recovery, and then your recommended strain. And we give you very concrete strain recommendations. And we have science backing up that if you meet those strain recommendations, there's ephacious outcomes behind that.

So do you want to talk about some of that data? Yeah, yeah. And this is such an exciting finding. I mean, so validating, right? You know, I think one of the charges of our team is does work, right and and we found that our strain coach when folks listen to it and to your point meet their daily strain target they actually get fitter and and i think what's what's really exciting about about this i think knowledge is that this the under the foundation of our of our platform and of our system which is based on this toggle between strain and recovery the strain targets we're giving you are based on your capacity to take on that strain, right? So your recommended target is based on just the cumulative load to that point, right? So we're

not going to tell you to meet a strain target that you're not capable of meeting. Not just the load, but how you're responding to that. Exactly. So I think for folks who are coming on to our system, who maybe haven't played a lot of sports, it just wasn't part of their life, right? They don't maybe have some of this intuitive sense of like when to push, when to, when to hold back. And I don't even argue some elite athletes don't necessarily have that a real good sense of how to balance that, right? Because your ego takes over. Yeah, you're not, more is not better.

More is just more generally. So, yeah. But I think that, that to me is what is so sophisticated and, and I think intuitive about our product is that, you know, we're really able to guide our members. around how much strain to optimally put on your body that gets you into a bit of an overreach, which will allow you to get fitter, but without compromising your ability to show up tomorrow, right? And we know in order to get fitter, consistency matters, right? Like, you know, showing up, you know, training consistently is really how you get fitter. And I think that's what

we've been able to achieve with this balance between strain and recovery is, is we give you a recommendation that can push you a little bit, but not so much where we get a diminishing return. Yeah. Right? And I think that's what's so beautiful about those data. And it's really validating, obviously, our whole infrastructure in terms of how we're, the insight that we're giving you about when to go and when to, when to hold back and how hard

to go. Yeah. No, exactly. I reminds me the consistency point. I had a soccer coach in high school, which is over 20 years ago now, which is scary to think about. And he would get up there in his old umbro, you know, swish-wish pants and his, uh, in front of the team. The umbra track suit. I know that's exactly what you're talking about.

You could smell the oldness like coming up. And he would put his hand in this pocket. Variety is a spice of life, but consistency pays the bills. And like you said, we give members personalized strain recommendations based on the load that they've taken on, but how their body is responding to that load. That's reflected in sleep and recovery. And while we give you a day target for strain recommendation, we also realize that strain shouldn't be given as a target as a single concrete metric. So we give people lower strain and upper strain recommendations, and that's very intentional. You know, you don't necessarily if your strain target is 12.5 during that day, the body can't tell probably the difference between a 12.3 and a 12.6. Right.

So anywhere in that recommendation. But importantly, we're giving you lower bounds and upper bounds because the key to that consistency is not to do the same. thing day in and day out. You're right. And Steve Magnus talks about this all the time, that in high-level performers, love Steve. The key to success is putting in the work, but also being able to show up and continuously put in that work. And so what that involves is not going out and killing yourself every day. And there are days when you're not as receptive to taking on stream. And so those days, maybe a good walk would be totally fine. I actually, a couple weeks ago now, I, you know, was up here and then traveled.

And I, you know, got to my destination. And I was like, oh, I'm feeling kind of tired. So I actually pulled open AI coach and I was like, should I like exercise now or like have lunch? And it's like, it's like, after a long day of travel, maybe just like have lunch and go for a walk that afternoon. And that night I was like out walking. I was like, man, this walk is like crushing me. I'm like so glad I didn't do any like exercise during lunch. And that's what we're providing.

And so when we're looking at our strain recommendations, realize that yes, there's the number that we're We recommend you hit, but there's also the lower and upper bounds. And strain, again, it's not always the more, the better. So I would pay attention to the lower bound and the upper bound and try to fall in that range. And also- And go and based how you feel. And that's exactly what I'm going to say. If you feel really good, hit that upper bound, you know, and don't be shy about that, you know, and own it.

And yeah. Yep. And also realize that some days we may not need to listen to our strain targets. If we have like a really poor night of sleep the night before a race, listening to the strain target may not be what exactly is going to get you to your goal during that particular race. And strain, again, being the backbone for building fitness. And you talked about the wonderful data from Jane and Bill Von Hippel showing that over 12 weeks, I believe it was, members who meet their strain target are more likely to increase their HRV.

And I believe we saw 10% increases in heart rate variability. Yep. And now the whoop is on. Cardi respiratory fitness improves. Yep. And now the whoop is on a mission to improve and unlock not only human performance, but also health span and our team looking at health outcomes. We know we have some wonderful data from our recent Pire, Jenna Cohen, our scientific communications associate, showing that not only is meeting strain targets associated with HRV, which we show as well, but also

reductions in resting heart rate and even more so clinically meaningful weight loss, that members who meet their strain targets and have a goal to lose weight are more likely to lose weight, but also more likely to achieve 5% reduction in body weight over a 12-week period and really getting at that help outcome. So strain is not just about improving fitness, but now WOOP is giving definitive action-based recommendations to help you achieve your weight goals. I mean, that's the whole reason we work at this company is to try to, I think, develop a product that is actually driving outcomes.

Yeah, and you and I get all is up here and we talk about how it's the same principles that apply for improving fitness and making people better athletes that are also going to improve outcomes and make people healthier. And now we don't just we have more than to be able to just say that. We have the data to prove it. So those data are coming out very soon. Who in your life is ready for their healthiest summer yet? Maybe it's a friend training for a big event, a spouse building better habits, or someone looking to take a more proactive approach to. their health. Refer a friend to WOOP and they'll get started with one month free along with personalized insights into their sleep recovery and overall health. Plus, from June 27th through

July 7th, when they become a member, you'll earn two free months added to your membership. Open the Woop app, grab your referral link, and kick off your healthiest summer together. Do you want to talk about how strain may be feeds into improving cardiorespiratory fitness and the value of that from the health out perspective? Intensity matters. And I think that's where strain, I think, is really valuable in that. And when we think about outcomes, we need to be smart about how we're working our heart. And maybe this is where we talk about heart rate zones, right? And this is kind of how I think about your question in that we want to getting out and doing anything is better than nothing, to be really clear. But if we want to, I think, get to a,

a path that is most efficient in terms of building our cardiorespiratory fitness, there is a way to kind of think about that, right? And in strain coach is, I think, an excellent, I guess, place to start in terms of, all right, if I am highly recovered and, you know, Woop is recommending that I hit a 15 strain, you know, what is the path to that? And there's a couple ways you can do it, right? And so it considers what your lifestyle is. For someone who travels all the time, going out for a two and a half hour walk to hit your strain target. It's probably not realistic. So do you want to maybe give some personal recommendations? Yeah. And this happened to me just the other day. I, I woke up highly recovered. I felt really good. And I'm like, I'm going to hit it hard today. And I didn't have a

lot of time, though. So I did one minute intervals on the treadmill with quite low rest. So 30 seconds rest. And I repeated that 12 times. Now, that only took me, you know, less than 30 minutes. But I was at a 15.3 strain at the end of that, right? So I worked my heart very, very hard. So I thought about, okay, how do I meet the strain target in the shortest amount of time? Well, I need to do some volume, right, but reduce my rest time, right, in order to like really keep my heart rate up there. And then after that I did, you know, some ground overhead. I did, you know, some functional strength. And then I was done. I was out of there in 35 minutes. By the end of it, I, you know, I think when I look at my total strain across the day and maybe we can talk about this, I was like at a 17.

which is above my strain target. That said, you know, that's not just obviously my work at out in the gym, but that was also public speaking and just getting to the airport and all of the moving around that's happening over the course of the day. Like that total load is an important consideration. And yesterday when I woke up, you know, I was less recovered. And I did very light functional fitness and mobility. Didn't work that hard. You know, I kept my strain low, essentially. And then this morning I woke up, woke up and I'm pretty recovered.

and I went for a nice long run. So it helps you think more intentionally about how to apply your effort. And I think for me it's just like this amazing just guidepost, right, to just organize my workouts and my day in a way that allows me to show up tomorrow, which again, I think that's the working principle here is how do you create a scenario where you can train consistently? Because we know that is the path to kind of health and longevity, right? Is consistency.

Yeah. And I think kind of speaking to the same point we're talking about here is that strain can come from different ways. You can get a high strain from spending a lot of time. Maybe when my grandpa goes out and plays golf for four hours, walking around. Gardening for three hours. Yeah, in zone one and zone two, if you have the time. But if you don't have the time, it can be just as effective to accumulate strain by spending a shorter amount of time in higher intensity zones. And I would actually encourage members to use the AI coach to consider their history and their situation.

And get workout recommendations. And get workout recommendations. And the neat thing is that from a scientific perspective, we know both of those are ways to build fitness. You can do a lot of lower intensity zone two time to build fitness. And then there's all the work from, you know, really coming a lot from Marty Cabala's lab, showing that like you were talking about really high intensity, 30 second, 45 second intervals can be equally as effective to build fitness. And so some of that comes down to what type of time you have in your life, but also personal

preference. And so members can build strain really either way. And that can be a way to improve fitness either way, right? And we think about strain from the context, I think it's important of public health guidelines for physical activity. And that's really what strain is. is reflecting is physical activity. We know that we're recommended to achieve at least 150 minutes of moderate intensity physical activity a week. Which would be our equivalent of zone two, three,

yep, maybe a little bit of four. Yep. Yep. And members can, of course, follow along with what their heart rate is during a particular activity. Yep. If they so choose, right? Or if you have less time, perhaps, it's suitable to replace that with 75 minutes of vigorous or four to five, zone four to five activity. Really interestingly, I was actually just looking at a paper over two million individuals and it showed that from multinational cohorts compared to those who weren't meeting physical activity recommendations, those who were, were 25% less likely to die over a 11-year period. And so again, strain, health outcomes, improving fitness, but also providing people with recommendations that we know is going to help them live longer and

healthier lives. Love it. And all that's mediated by them building cardiorespiratory fitness, which is V-O-2 Max. Let's talk about V-O-2 Max. We passively detected. You know, this is just, I think, one of the coolest things that we've been able to do at WOOP is be able to give a pretty damn accurate estimation of your V-O-2 max without having to get you into a lab.

So perhaps talk about very briefly, just about that process of arriving to a place where we can accurately detect V-O-2 max passively. And why does that matter? Yeah, I'm just going to put a stake in the ground and say there's debate, but I'm pretty confident that V-O-2 max is the best predictor of health and longevity. Higher VO-2 max, the harder to die. Yeah, for sure. And there's data that goes back to 2002, and we have a whole episode on this from just. Jonathan Myers showing that a very small, relatively small increase in V-O-2 max, one med or three and a half milliliters per kilogram per minute, you're 12% less likely to die. And then a paper that came out from the same group 20 years later, stratified people by their V-O-2 max. And it showed that people who were in the highest fitness group compared to those in the lowest fitness group.

And this is almost a million people, longitudinal study, were four times less likely to die. Yeah. And the best thing about V-O-2 Max is that it's most movable or it can be improved the most in the people who aren't doing anything. Right. And also the health and longevity benefits that come from VO2 Max, they also are not linear. They're greatest in those who go from that lowest fitness group to the group that's just slightly more fit. Or if we look at it from a daily habits perspective, those who are total couch potatoes to those who are just getting up and maybe walking the dog.

And we even have data showing that actually having a dog is associated with better fitness and better sleep. But that's a whole other thing we don't want to get into. But I think that speaks to the importance of VOTOMX. And so last year we rolled out with the VO2 Max estimate for our members. As you said, we can use entirely. Two years ago now. years ago now. Two summers ago.

Yeah. Time flies. I'm glad you corrected me. As soon as I said that, I was like, might have been two years ago now. Definitely. Yeah. And so that can be done passively or for members who want a bit more of a personalized and even more precise recommendation. Do that 15 minute test. And it doesn't even have to be totally maximal.

They can just go in and run for 15 minutes. And we know that's going to improve on the accuracy of the number they're getting. And again, the best way to build or improve V-O-2 max that we know is by following and meeting strain recommendations. So we're giving you those strain recommendations to improve B02 Max, which is important for all the reasons I just outlined. And we have a whole other hour-long episode that dive some to that. There's a couple of protocols that are particularly helpful. One is the eight minute on, two minutes off. That is actually the most efficacious. I was reading an article by that Danny Ploos surfaced recently on Instagram. You just posted that one on

Instagram, right? Yes. And I was like, oh shit. I've been doing the four by four. The Norwegian protocol. He's Stephen Seiler and the Stephen Seiler stuff. Yeah. And he's like, well, you know what, honestly, like four by eight, four by 16, you can really improve VOTU max, any number of ways. But I think, you know, it actually intensity matters, but volume actually matters too. And I think that's the takeaway from that post is that volume matters.

And, you know, if you really want to do the most application protocol, it looks like it's the one that came out on top. And that study is the eight minutes with two minutes off. Yeah. And I do think. times four. There's 32 minutes of just hellacious work. There's those data, but then there are the data in, and I'm forgetting, I think it was maybe

Jan's Bangsbo, someone over in Europe, and they took these cyclists who had been doing a lot of the kind of textbook six by five minutes with two and a half minutes off, and they had them do much more high intensity efforts of 40 seconds on, 20 seconds off, and appreciably improved the O2 max. Yeah. I think the short of it is exercise and straining is the way we improved the O2 max. Consistency, we know in our own data, consistent exercise, consistent sleep, people have the highest VO2 max. And also, I think important is that the human body becomes very good at adapting to the stimulus that it gets.

And so I think a lot of people do fall into kind of a bit of a trap of, well, this is what I've been doing. This is where I am now. And they don't change it up. And I think people like you and I who thrive on stability and consistent schedules maybe tend to, fear like changing it up. And the truth of it is, I think it is that deviation from your normal routine in far as like maybe there's something different than six by five or four by four, right? And I think that was kind of maybe one of the purposes of Dan's post is that the body does well when it gets different stimuli. So sometimes giving it that little bit of an extra shock,

whether if you've been doing four by four going to four by eight or if you're someone who's always been doing 30 second intervals, maybe give the body a 20 minute interval and see how it likes that, is important for adaptation. If you are already highly fit and are kind of like close to a ceiling, how do you think about V-O-2 max in that context? Yeah, I think if we're thinking about it from the perspective of health and longevity or from athletics, I think it's important to realize that VO2 Max is a big central piece of the puzzle, but it's not the only piece, right? For health and longevity, we know V-O-2-max or cardiorespiratory fitness carries a lot of weight. And I already made the statement that I think it carries the most weight, and I bet a lot on that. But other things

like metabolic health, which are highly correlated with V-O-2 max, but those are also also playing a role. Musculoskeletal health and doing weight training, I think. And we've seen actually a lot of our members, tens of thousands of them have paid attention to these data when we've released HealthSpan. We've showed now when we have data that Dylan is currently working on, right, showing that when we release HealthSpan, tens and thousands of our members went from not doing resistance training to now they're starting to do resistance training. And so I think keeping in mind. So many folks just in our building, employees of Woop who had never strength trained before,

all of a sudden are now doing it, which is such a cool function of health span, right, which we're not going to get into today, but strength training minutes is one of the inputs into health span. It's one of the metrics that we're, that goes into kind of that health span algorithm. So I think realizing that every individual probably does have this upper threshold for V02 Max. And the truth of it is most of those adaptations are going to come from the first three or four months of training. VO2 Max increases are not linear. They're going to go up and then they're going to kind of, you're going to hit a plateau. But realizing that there are other pieces of the puzzle from both the health perspective, but also a fitness perspective, even running a marathon.

You know, people often think that, oh, higher VO2 Max is going to win a marathon. Well, if that was the case, I don't even know if I'd be working here because I have a very high VO2 Max. No, I would. Of course, I love this job. And there's a genetic component to that too. To V02 Max for sure. But for distance running, Michael Joyner has published, who we've collaborated with on a couple

papers now, published data and written opinion pieces and reviews showing that for running, endurance success is going to be determined by VO2 max, but also lactate threshold and running economy. And you can have a really high VO2 max case and point with a very low lactate threshold or a horrendous running economy. And so if your VO2 max is very good, I think it's probably time

and maybe that's optimized. It's time to think about the other pieces of the puzzle. So how can we train to improve our lactate threshold? Or how can we train to improve our running economy? And strength training and running economy, there's correlations there. So anyway, I think realizing that VOTU max is very important, but it's not the only piece. Yeah, I think it's a great point about lactate threshold. And there's certainly ways to train that, basically just have to run really hard for extended periods of time.

Yeah, the lactate threshold's probably not going up. I mean, in some folks, it might from the zone one or zone two walk. It's not. Yeah. Yeah, there's a. You got to get into zone five. There's benefit from the discomfort coming from lactate threshold. There's also a lot of research around, and this is why this kind of upper, like, maximal

heart rate work is so important, is that it impacts the brain in really important ways. And we're seeing kind of relationships between lactate and brain health as well. Yeah. And the processing of it and Nicosanelon, lactate threshold, lactate processing and cancer and all, yeah, all sorts of. Absolutely. So I think getting out of breath a couple of times a week is going to improve your VOT2 max. but it's also going to reduce, I think, the risk of things like, you know, neurodegenergendor diseases. And, you know, I think that research is really coming online now in ways that are powerful.

Yeah, Alzheimer's and Parkinson's. That are these things that are coming as we get older. Yep. And high intensity exercise in particular. Yes. Yeah. So, yeah, so it's a shout out for, you know, just for folks to get out there and really work the heart, you know. And I think that to the earlier point, you know, you can get just in 10 minutes.

you can really work your heart hard and then you're done, you know, which is kind of cool. Yeah, yeah. That's what people prefer that way. Yeah. You're invited to join the waitlist for WOOP Advanced Labs. Advanced Labs delivers clinician reviewed lab results right into your Woop app for the most complete view of your biomarkers and biometrics and the most comprehensive understanding of your health. Unlike other tests, whoop integrates your lab results with your Woop data. See how your habits and behavior. influence your biomarkers and get clear guidance on what to change to improve your results. To join the wait list, visit our website or the health tab in the Woop app.

We talked a little bit about this idea of balancing strain recovery and how that actually drives process. Maybe let's just hit that on that point a little bit harder because I think that that, you know, I just wrote a 350 page book about recovery, right? Like, so obviously I'm a I I believe that recovery is actually how we make progress, right? But you got to put into the work, right? Yeah, but strain is ultimately breaking down the system. Exactly. There are no benefits at all that are coming from strain.

Without recovery. Exactly. Right? So because strain essentially is a catabolic state, right? You are like, and you're creating all these perturbations physiologically, these stresses physiologically that are so important. to human health and functioning, but they only can be positive when we're carving out the time to optimally rest. And we do that obviously through sleep. That's the best time to restore and

regenerate from all the work that we've put in today, right? That's the best, gives us the best chance to adapt positively and to capitalize on all that work that we did. But it's also, I think, taking a nice long walk in nature or just carving out time to you know, recover from the work that you've done. Okay, Greg. So you wake up with just like a killer recovery. You know, you just feel good. You feel totally restored. What's going to be your go-to workout? How do you build strain? Yeah. I mean, my favorite is running. I like being outdoors. Recently, I've been kind of playing around with like running with headphones and not running with headphones. And I will just like, I'm just going to like make a strong case. I feel like we live in

this like hyper-connected world. And like my mental capacity on days when I I've just like it's kind of been like a personal experiment for me of like not running with any sort no no phone no headphones just get out and run and like it's crazy how much my mind works better on those days so anyway I like to go out and run really hard uh generally I'll do like six to eight miles of hard running continuously um and and generally after that the 15 to 17 strain is achieved yeah yeah how about you yeah I think uh it definitely varies for me, but I also love, love, love to run. And I also similarly very much experiment with, especially when I'm able to run on a trail in nature, very rarely will I be listening to anything.

Yeah. But I do love, you know, on a longer kind of zone two type effort, I do love listening to a podcast and maybe some music. But, but yeah, I've definitely become more intentional about, you know, just being able to listen to the birds and, you know, in the winter, just. the absolute quiet, you know, of a cold day in the forest, you know, it's pretty amazing. Yeah. I think it's like character building when I just go out and it's like, all right, I'm going to like get in zone four and then just suffer here for the next 40 minutes. It just makes like the rest of the day feel just so much easier.

Yeah. Like anything that comes at me, I'm just like. I do love those like continuous hard runs, you know, where you're just just pushing. Yeah. Nothing really feels better after. All right. So how are you winding down after that? What's your recovery?

Yeah. I mean, I love the sauna after cardiovascular efforts. I think for me, as long as I'm appropriately hydrated, that actually feels quite restorative. Now, I'm not, I have a red light sauna. So I think that makes a difference. I don't know the data post-exercise. I think it's positive for both, but I would probably say in a dry sauna, you want to maybe limit it to 10 to 15 minutes. But I think in a red light sauna where you aren't achieving those higher temperatures. There's less sweating, but I think all the benefits of a dry sauna, you can go 20, 25 minutes, you know, pretty comfortably. So I really love, I love getting into the sauna after a long run and just kind of stretching and breathing and probably my favorite. And I do love, you know, just mindfully walking, you know,

and just kind of noticing the birds and the leaves and the, yeah, that feels very restorative to me. Yeah, that's awesome. Yeah, what about you? I like probably gardening. Like nothing says I'm getting to my 40s, like the fact that I really enjoy going out and like playing in the garden. I mean, I watch birds, so that doesn't give you a sense of just. You're almost 42. Yeah, exactly.

So I think the big take-home message, listen to Strain Coach. Yeah, listen to Strain coach. Yeah, and strain's going to help you live longer. And we're providing you personalized, evidence-based, clinically proven ways to, help you get fit, stay fit, and live healthy your life. And if you don't know what to do, coach is there for you, 24-7, to help you think about how to put strain on your body in a way that's most effective and efficient, works with the constraints in your life.

Just tell coach what you can do, what you can't do, if you have an injury, you know, coach is going to guide you. Coach is regularly asking you about my knees. I know, I know. Also showing I'm getting older. Exactly, exactly. I love it. Well, thank you so much, great.

Thanks, Kristen. Appreciate it. 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 answer it on the podcast, email us, podcast at Woop.com. Call us 508-43434952. If you think about joining Woop, you can visit whoop.com. Sign up for a free 30-day trial membership. New members to use the code Will, W-I-L, to get a $60 credit on W-A-W-A accessories when you enter the code at checkout. That's a wrap, Thanks, thank you all for listening. We'll catch you next week on the Woo Podcast.

As always, stay healthy and stay in the green.