WHOOP Podcast - Understanding Heart Rate Variability and the Impact on Strength Training with Chris Chapman

Episode Date: April 19, 2023

On this week’s episode, WHOOP VP of Performance Science, Principal Scientist, Kristen Holmes is joined by WHOOP Senior Sport Scientist Chris Chapman. Chris is also the Lead Strength & Conditioning Coach of the Big Air / Slopestyle Team for Freestyle Ski Canada. Kristen and Chris discuss how Chris got into Heart Rate Variability (HRV) and how he applies it to training (3:40), how to assess training readiness in athletes (7:35), components of a strength training program (12:30), what is HRV and why it is important (18:45), how HRV is impacted by strength training (26:15), how people are adapting their HRV (34:00), how HRV can influence exertion and performance (45:45), recovery tools and tips (48:15), dealing with stress while training (54:15), and how age influences HRV (1:00:20).Resources:Oliveira 2019Williams 2020Thamm 2019Flatt 2019Figeuiredo 2015Marasingha 2022Support 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

Hello folks, welcome back to the WOOP podcast where we are on a mission to unlock human performance. I'm your host Will Amit, founder and CEO of Woop. Got a good episode this week. It is Woop VP of Performance Science, Chris and Homes, being joined by Woop Senior Sports Scientist Chris Chapman. Chris is also the lead strength and conditioning coach of the Big Air Slope Style Team for Freestyle. Canada. The strength and conditioning expert is also a certified exercise physiologist and a high performance specialist through the Canadian Society for Exercise Physiology. Kristen and Chris discuss the key components to a strength training program. Chris shares some methods his pro athletes use

that anyone can incorporate into their program. How Chris pays attention to HRV. H.RV's role in strength training. The recovery tools Chris incorporates into his training programs, breath work, meditation, how he's worked in even the stress monitor, and how important being in the right mindset to train and perform can be for an athlete. Also an exciting time for those of you on Whoop because we just came out with impacts. That's right. You can now get daily insights and information on how your behaviors and habits impact your recovery. You can find this feature by going into your WOOP app and selecting the coaching tab. You hit Insights at the top, and you will now see how all those things that you've been monitoring in your WOOP journal, behaviors, lifestyle

decisions, you name it, affect your recovery. So it's a pretty exciting feature. Check that out. If you're new to WOOP, use the code W-I-L-L when you're checking out, get a $60 credit on W-WIP accessories. If you have a question, you want to see answered on the podcast. Email us, podcast at Woop.com. Call us 508-4-4-4-3-49-2. here are Kristen Holmes and Chris Chapman. Chris Chapman is the lead strength and conditioning coach of the Big Air Slope style team for Freestyle Canada and also a senior sports scientist here at Woop. Chris is a strength and conditioning expert receiving certifications in sports science,

exercise physiology, strength and conditioning, and holds a Masters of Science in Biomechanics. Chris has worked in the Strength and conditioning industry for 20 years, primarily with Canada's Olympic sport. Chris specializes in training acrobatic and endurance athletes, having coached athletes for seven Olympic games, both in the summer, canoe kayak, trampoline, cycling, and winter sport, freestyle ski, ice hockey, and figure skating. Chris was instrumental in helping build push, a Canadian sport technology company that was recently acquired by Whoop. And we'll say that, as an aside, I'm around a lot of nerds on a daily basis, and Chris is at the very tip of that sphere. That's a compliment, Chris. I take it. I love nerding it. I know, I know. You're just one of the, just I love every chance I get to talk to you is like

a joy for me. So just really appreciate everything that you bring to, to whoop and just how you've, you know, leveled us up in just every way as it relates to all things sports science. So thank you for that. To kick off the pod, so our conversation today is going to focus on heart of variability. We'll refer to as HRB and how to think about. it in the context of strength training. Chris, would love for you to start off with how you initially got into kind of HRV and how your application of the data has evolved over the years. Yeah, so HRV, I first got into it early on in the days at Push. I started consulting with Push in 2014. A velocity-based training was their big focus. But they ended up getting a contract to work

with the San Francisco 49ers. And this is when Mark Yu-Iyama was the head of performance. And Chip Kelly was the coach. And Chip had a vision of creating a monitoring system for all the players. And the concept was every morning, they go in for breakfast, they walk through the locker room, they step on a scale, they get their weight, they do a subjective questionnaire, and they get their HRV. And we were using the I-Fleet system at the time, which was a wired finger sensor. This was before wearables were a thing.

And then they would check out again later in the day. And, you know, do things like compute how much fluid they needed from weight changes. It was kind of the first vision of a monitoring system. And that's kind of when I started going down the rabbit hole in what is HRV and why is it important. Because I had never really seen or heard of it before that. So funny enough, it was the NFL that. that got me on that path. And then...

What year was that? Spending some time. I was 2015, 2016, some time around then. I don't know exactly. I came on to push full time in 2016 after the Rio Olympics. I was the head strength coach

at the Canadian Sport Institute in Toronto. And I kind of left my position there to just try something new. And I wanted to go down the tech rabbit hole just nerding out. I love tech. I grew up around it. and wanted to change the industry of velocity-based training.

Then that brings us to recent when WOOP acquired push and brought us in-house. And given that, I started using WOOP and I got a set on my current team, the Big Air Slope-style national team, and I've just been going down the rabbit hole ever since. I think it's the new form factor is the biggest game changer, the ability to have a 24-hour wearable.

Trying to do this stuff previously. Like we even switched at push from the athlete sensor to the elite HRV because it was wireless. But even just the friction of the ultra-short finger sensor collection, compliance was never 100%. Yeah. And now that you can do it while you're sleeping, it just takes away any of the compliance issues. I don't know if trying with the heart rate straps as well. trying to get athletes to lie down or sit down and put that on every morning,

especially when you're not there putting it on them. Yeah. It just was too much friction. Yeah. I know. I experienced that at Princeton, too. The only time that we could take it to fit within our basically two hours of allotted time that we had with the athletes was literally before practice.

So we had to do so much modeling to just, you know, be able to reliably take this kind of time point and this measurement and be able to kind of apply it to the training. not to mention it literally I would get their HRV reading and it's you know literally five minutes before practice so then I'd have to modify try to modify things based on those data it was just impractical on every level but so yeah I can I can totally relate to that so yeah I mean taking you know the I think the whole concept and I think what whoop has done is just brilliant and I think a lot of other you know technologies has followed in terms of taking HRV when there are no confounding factors you know during that you know during slowly of sleep and really extracting kind of what

you know, what is your recovery status? And I think it has emerged in the literature as being the most efficacious time point to really understand next day training readiness. If you want to kind of touch on just that as a concept, it would be great. Yeah. So prior to HRV, you know, we looked at subjective readiness using questionnaires. I've used the Hooper McKinnon mostly, but there's other ones like the perceived readiness score or, you know, there's a few others out there that have been used. Both are really good. Yeah, they're validated.

And then using some kind of neuromuscular assessment. So for the most part, it's been jumps. It's easy to do. There's lots of different tools you can do it. You kind of create a normative baseline and you look at changes day to day. Are they jumping higher, jumping lower? what are some of the metrics underlying the jump? Is the jump slower?

Are they taking more time to produce force? Or you look at a key performance indicator lift. So I worked with paddlers for a long time, and we looked at a bench pull or prone rope. And you can pick a weight or pick a speed, and you just assess it every day and do things go up or down. And that kind of gives you an idea of readiness. I think what HRV has done is brought a whole system stress,

readiness score and it takes into account the things that are away from training, the non-contact hours, as I like to call them. I can do the jumps when they show up for training. I can do the questionnaire before and after training, but then there's 20-ish hours to the rest of the day. What are they doing? All of those things that impact heart rate variability, right? I mean, that's the, yeah, that was my big insight too. And I was coaching. I was like, nothing I do to them in these two-hour period like really predicts their capacity tomorrow like it's just it's just the confluence of everything over the course of a 24 hour period yeah to keep going yeah to give you an example in my athletes um one of them skateboards non-stop when we're not on hill and he was getting

way higher strain skateboarding than anything we were doing on hill and so it's okay you don't need any supplementary cardio or energy systems training because you're getting all of that You're getting a lot of impact training too. You know, one of my colleagues with Snowboard Canada put IMUs on the skateboard with his team and saw that skateboarding has higher impacts for the most part than ski training. So, okay, he's getting his impacts. He's getting his cardio. It's taking care of a lot of the buckets of off-hill training for us.

So just answering those questions, okay, we know he's doing this much skateboarding. That's taken care of all these things. So let's focus on something else. That's a great vantage point. or a great way of thinking about it. I know that some of our NHL and MLB players on the platform were pretty dismayed when they learned how much nine holes of golf was actually impacting their activity. Yeah, it's kind of funny how you see just like a skateboarding on golf and just even yard work,

like how it kind of impacts that total kind of amount of strain that you're putting on your body and influences your hearty variability in profound ways. maybe just what if yeah go ahead if you have a point just on on how to think about hurry variability in the context of kind of wrote activity versus kind of what would be considered non-activity and kind of how that plays how they play ball yeah i mean i was just going to say i when i worked with the ontario golf team this was like 15 years ago uh that was we had an aha moment uh we were doing beep test like classic aerobic and we found beep test scores correlated extremely highly with handicapped scores so the more fit you were the better golf player you were and so people think a golf as like

a walking recreation maybe if you're carding it's different but you know they make the juniors walk their bags that it is an aerobic activity and it's going to affect everything you do so that was just what I was going to say on that one we've got a lot of golfers who listen to that so it'll appreciate get that little tidbit. Cool. Well, I know in the WOOP podcast 107, I just wanted to call this out, you, you know, really went deep on how to create an optimal strength training program. So we're going to kind of segue to HRV and strength training.

And I don't want to retread on that podcast, but perhaps if we can just provide, you know, anyone who hasn't listened to that or, you know, kind of inspire folks to kind of maybe go back to that podcast as a precursor to this podcast or folks who just don't understand maybe what the components. of a strength training program really look like, you know, encourage them to go back. But, Chris, if you just want to maybe just set the stage with a very brief outline of, you know, what are the components of a strength training program? Just how can people kind of think about it globally? And then we can kind of dig into, to hearty variability in strength training.

Yeah, I mean, there's two major components I like to look at if someone, I have someone new in front of me that wants to do strength training. One, what is their why? Like, what is their goal. They must be sitting there for some reason. And in my world and in sport world, there's a task demand. They have a task they're trying to achieve and they're trying to be the best in the world at that task or that task is paying their bills. So we call this demands capacity. What are the demands of the task that they're about to achieve? And are those demands, strength, power, speed, endurance. You know, general physiological qualities is their specific movement patterns. What is the times that they're moving? Like what energy systems do they need? But specifically with strength,

you can get complicated, but there's strength how much force you can move. Do I need strengths to complete this task? If I have higher strength, will this task be easier? There's a speed or power component. Do I need to move fast? If I move faster, will it make me better at this task? If I can do more work, will it make me better at this task? You know, your timed racing sports who can do the same amount of work

and the least amount of time wins the race in most of those sports. Endurance, can I repeat that same task over and over and over, whether that's a baseball pitch or like holding a windsurf boom? You know, any task where it's repeated over and over opposed to shot put where it's just I toss a heavy implement a couple times and that's it. But then we look at the capacity of the human or the person in front of me and what are their

capacities in those task demands? And do they have enough capacity to achieve that task? Where are the gaps and let's fill in the gaps? Do the capacities meet the demands, the sport? And usually when a capacity doesn't meet a demand, it's an area of opportunity for improvement, or that's also a potential risk of injury, because they don't have the capacity to do what they need to do. And this is a very biomechanics approach to it. There's a sub-discipline called ergonomics, which is, can we improve the human to meet the demands of the task, or can we change the task so that it's optimized for the human? And in sport, we can. can't really change the task. You can change some techniques. So it's all about optimizing the human

to meet the task demands. And I just love it because it's a very simple way to look at this whole thing. Now, let's say we're not talking about athletes or workers like firefighters, people who have a task demand. Maybe it's just people who want to look better, aesthetics, or they want to be healthier to live longer and enjoy life, or they want to improve their activities of daily living. An elderly person wants to have more function. That last one you could say is a task, but the other ones, then it's just okay. Let's, how do we optimize your, your aesthetics or your health? And that's almost a little, a little more simple because you're not trying to achieve some task. It's more, let's just focus on. Kind of component necessarily. It's, yeah,

which is more specific. Yeah, it's straight fitness. Yeah, it's straight fitness. know, it's nutrition becomes a much higher focus for sure. But then it's, it's about, you know, let's spend time in the gym, whether it's burning calories or increasing muscle mass. So I'd say those are the two simple ways that I would look at it from a general person who's sitting in front of me and what are they trying to do. What is the goal? And then what is the task? And what are the demands? And let's create capacities to meet the task. Or let's improve the capacities for the goals. Yeah, I love that. And I, I love thinking about it in terms of demand's capacity. And I've done a lot of modeling around this

myself, you know, from not a biomechanic lens per se, but, but definitely from like understanding what are the physiological and psychological variables that are going to move around our internal status, right? And we measure our internal status with HRV, you know, resting HRV with resting heart rate. Some of these other subjective components, you know, kind of give us a sense of your internal status. And then, you know, knowing, then really understanding, okay, what can I generate appropriate arousal levels, mental, physical emotion, emotionally, emotion to meet the demands of that task? You know, and this is, I think, a really, I think, important framework for people to think about, okay, what are the behaviors that are going to move around my internal status,

right? Strength training is going to move around my internal status, you know, temporarily, potentially in, you know, what we kind of perceive as a negative direction and not a suppression of HRV. But over time, we do it properly is going to raise our heart rate variability and raise our capacity, really, you know, to meet future demands at a higher level, right? So that's kind of what we're striving for. But I think this framework around demand capacity is really, really cool. I kind of, I call it demand match and demand mismatch. What I've seen, what I saw with my athletes over time is that, you know, the more demand match we have, you know, generally the happier, more productive that athlete is. The more demand mismatch you have in terms of this internal status,

you know, and not being able to meet the demands, obviously the less happy, you know, the more injured and the less productive the athlete is. So I think that is an amazing framework to kind of, I think, segue into this conversation around HRV specifically and how we can think about that to increase these demand matches over time. We've said HRV a lot. We've said HRV a lot, There might be some new listeners who just need a quick primer on what HRV is. So if you can maybe just provide a quick overview of variability and just why it's important, and then we begin to strength training components. Yeah, heart rate variability is a measure of your beat-to-beat.

So our heart beats, and those beats happen in a time frame. and sometimes that time frame changes a lot means there's a lot of variability between those beats or sometimes it's the same time each time. And it's a reflection of your autonomic nervous system. Now, I like to be simple. Think coach, but speak client is something a mentor taught me a long time ago. And the autonomic nervous system controls the processes under the hood,

the you know the things that you're not voluntarily thinking about you don't think about controlling your heart rate that's a response to what you're doing now there's there's the fighter flight which is the sympathetic system and that is as that increases your body is primed to do tasks that are high stress you know you it's it's the response you get when you're in a stressful situation, physical stress, mental stress. And then the other side of it is rest and digest, and that's your parasympathetic nervous system. And that is more recovery. And what happens is your body directs blood flow to different organs and different systems based on which one you're in. Now, these two systems, you know, it's a balance between them. Your fight or flight can go up

and go down or your rest and digest can go up and go down. And it's usually an interplay between the two. One of the things specific with waylifting that's interesting is a lot of the original research was using what's called a spectral method. It's not what the wearables use. They use a temporal method where the spectral method can look at both the sympathetic and the parasympathetic and look at which one's driving the response. And one of the caveats with a lot of things we're going to talk about is that this research hasn't been repeated using the newer methods. A lot of it, it's coming, and there's actually a really good review that came out last year on this, but we still need a lot more research with resistance training and HRV. So we're starting to

see trends and we're starting to know things, but it's still not fully conclusive yet. I think the other thing with the research specifically around HRV and weightlifting is that a lot of it was done using chest straps and using ECG and using finger sensor methods, not with the wearable methods. So we can't fully assume that all this transfers over to the very new school ways, but that research will get there. I do think there's trends in the research that we can hang our hat on. And the recent review and meta-analysis from last year kind of solidifies that. They've looked at all the research in this space, and they can make some, you know, conclusive statements based on what the research as a whole says.

Yeah, so long story short, I think that may do justice. Fight or flight, rest or digest, the more rest or digest we are, the more we can recover, the more fighter flight we are, that might prove advantageous during our sport or our activity. And would you say that, is it fair to say that you're, how responsive your heart is going to be to the demands of the autonomic nervous system. That is, you know, its ability, you know, we're constantly kind of sending signals to the heart. And the heart's responsiveness is kind of based on your heart's responsiveness will be impacted by how you sleep, the food that you're putting in your body, your hydration level. So all of these behaviors that are actually

quite modifiable and controllable impact your heart's responsiveness to the demands of the on the nervous system. Is that fair to say? And is there anything you'd want to elaborate on there? I think so. I think everything we do, and that's why I like it as a general measure of overall stress on the body. And we're kind of state we're in. It's tough to micromanage all that stuff specifically as a coach and someone who uses it on myself. You know, you got to pick and choose the buckets you're going to focus on and the rocks you're going to move um you know i i'm not a big proponent of micromanaging um because i just think it's just too minute and in the weeds and it doesn't flow with um everyday life and and just enjoyment um and you get lost in the weeds so

i agree with you that all that stuff matters but i don't think we can focus on all of it at the same time. So find where the biggest gap is, you know, the demand mismatch, as you say, I like that. And focus on that. Like maybe it is obviously, you know, we measure sleep. That's one of the first places I'll look. That's one of the best performance enhancing drugs we have. It is legal as, you know, stack sleep as much as you can. Let's start with the big rocks first and move those. I love that. I think it's such an important point. And as a coach, it just gets overwhelming, right, when you're trying to do 60 different things at once. But I think the approach, not just for athletes, but for anyone who has a body, you know, who's interested in improving their kind of longevity or in their health, it's, okay, how do I actually apply my effort?

Like, what are the things that are going to move around my ability to adapt to the environment in a functional way? And HRV is a measure of that, right? My ability to adapt to my environment is, you know, HRV is a great proxy to kind of. to help us understand how we're adapting. So understanding what are the levers that I can pull that will improve my ability to adapt in a functional way. And sleep is obviously a huge lever, right? And stabilizing when you go to bed and when you wake up is a massive lever. Thinking about proximity of meals to when you intend to sleep is another big lever. Hydration, a huge lever. Minimizing alcohol, a huge lever. So if you just even did those four things, you'd be 0.01% of the population,

in terms of getting it right and really kind of setting yourself up at a foundational level to be able to respond and adapt to your environment in a functional way. So agree. I think it's really about, and if Whoop is doing its job, it's helping people understand how to apply their effort so they can have more control over their ability to adapt to their environment. And this is where I think, you know, strength training is very, very interesting and a huge opportunity for folks to improve their adaptive capacity, right? Because there's this beautiful kind of hormetic, you know, thing that's happening when you're lifting weights that really does, is super helpful for, again, anyone who has a body, right? So what would you, in terms of thinking

about how, what can people expect when they begin strength training? What can they expect to see in their HRV? And how might they leverage that insight to modulate their strength training or to think more clearly about the impact that strength training is having on their on their system. Yeah, so from an acute bout of resistance exercise, so you do a session, there is a response in HRV. HRV will drop for the most part, and that we can get into some of the details on what might make a drop and what might not. There's a lot of underlying physiology happening, and I don't think, I'm probably not the best person to talk about that and don't need to go into the weeds, But from what we've seen in the research, basically, the number one factor in strength training that will create a drop in HRV is the volume of training.

So how much strength training you're doing? That's your sets times your reps, times your weight. Classic volume load. So the higher the volume load is, the greater the effect will be on HRV. And even when volume load is controlled, so there was one study where they controlled the volume load and they did an upper body workout. They did a lower body workout and they did a whole body workout. And what they showed is that the more muscle mass you use during a strength training workout, the greater the drop will be in HRV. And it's proportional. So given that

even when the volume is controlled. Secondary to volume, the intensity of the workout will cause a drop in HRV. Some studies have found there's no specific threshold. There was one study that found that once you go above 70% of your one repetition max, so the most amount of weight you can do for one rep and then take 70% of that. That seems to be the threshold, once you go over, that we start to see changes in HRV. And then the other one would be... What can we assume from that?

Like, is there, you know, I always think about it in terms of what, what is the, our gains that we might make once we kind of get above that threshold, do they come at the expense of health? You know, I kind of wonder, you know, we always think that, you know, performance in health sometimes are orthogonal, right? Like, and I think that this is a really interesting question, right? as someone who, I mean, for me personally, like, I'm not lifting, you know, I'm not performing necessarily in the sense that I'm not trying to be, you know, make the Olympic hockey team anymore. Like, that's not a goal of mine. I'm really just trying to like have a really high quality of life and, and be able to, you know, increase by longevity.

So just wondering if you have an insight on just that, that fine point. Yeah. I mean, I think that training for longevity in life and training for performance, They are two different things. And I do think that especially at high-level sport where it's a career and you're at the elite top-end threshold, that it can do, to get to that level and to succeed at that level, there are some things that aren't beneficial for your head. You're pushing the limits of the human body and it will break at some point. You've got to try and find that threshold of how much can I do without a break? And that's where I think HRV is a valuable addition to the monitoring toolkit in that, okay, I can see that when HRV is dipping or my recovery's in the red and it's depressed for long periods of time, okay, we're overtraining.

We're not just overreaching at this point. We're overtraining. And we need to be very careful about that. Now, there's some interesting things here that have been shown in the. research in that HRV does recover pretty quickly from a strength conditioning session. You know, typically within 24 hours, sometimes as quickly as 30 minutes. Now, if we look at a neuromuscular marker, such as a jump or a key indicator lift, it could be up to two days, sometimes even longer, but it depends on how hard you're training.

But the interesting point is that muscle soreness can persist far long beyond that, up to 72 hours. depending on the type of training you're doing. So even though we can be in a recovered state from our HRV, and we can be in a recovered state from a neuromuscular performance standpoint, pain and muscle soreness can persist. And whether that's perception or actual mechanical muscle damage, it's hard to know which it actually is, but understanding that you may be ready to perform from all our,

other markers, but you're still feeling pain and soreness, which you do have to take that into consideration and take your feeling and perception of that. But you can also use it the other way around and that just because I'm sore, everything else looks good. So you know what? I'm going to perform today. And I think one way to use HRV with training in general, but you can do this with strength training, you know, if I'm having an average day where I'm within my baseline, you know, just keep training as normal. If I'm higher than normal, like my body is highly recovered and it's ready to take on strain, I can push myself that, whether that's adding more volume or adding more intensity to try and create more stimulus, create more adaptation. But I

think the the way that it tends to be used is more on the other side in that if my HRV is still depressed when I'm about to go do my next session, I can do one of two things. I can delay the session and maybe wait another day. And there's a study that actually did that as they looked at, you know, just a regular scheduled training versus an HRV modulated training where if it wasn't back to baseline within 24 hours, they waited another day. But what they actually found was that the HRV training did the same amount of workouts in two weeks less of time. It was five weeks versus seven weeks to get 20 sessions of training it. So using HRV, you could actually accumulate the same amount of volume and work in a much less period of time,

which that shows us that just using a scheduled training session, we're not maximizing our potential adaptations, that we can train harder than that. which is so hard for practitioners who are trying to plan and have big teams and I totally can appreciate the challenges associated with individualizing plans based on HRV. But if we're actually looking to maximize individual potential, that really is the path. And just one question on that. And you said they looked at a three-day trend of HRV and not just an acute kind of daily HRV. I just want to make sure that that is clear. Because how I think about it, I look at my HRV. CV over the course, you know, like I'm not really to then plan my week training as opposed. So I look at my

individual variation day to day to understand how I'm adapting. So I don't necessarily look at acute HRV, nor did I do that for my athlete. So I guess I'm just wondering what, what is more useful is just, you know, is it, okay, I look at, hey, what I did last week. And I look at my adaptation of the course of the last week. I look at my HRV CV. And then, and then I plan this week based on kind of how adapted yeah this study specifically they they computed a baseline and they used the smallest worthwhile change which is a way to compute is this change actually meaningful or not and then they actually did look at the acute score and it was if it's not back to the baseline within 24 hours another day was taken rest before the strength training session was completed

versus a fixed fixed schedule of a monday wednesday friday i don't remember of the exact details, but we have the study. We'll put it in the show notes after so people can dig in. But back to the point I was saying before, so I was continuing my train of thought here. I think the way that I see it used, and one of the ways I use it is when HRV is still depressed, how do we modify training so it's not as intense? And you have to remember in my world, I have athletes that are performing a high acrobatic skill with extreme risk of injury and potential death during the sport. So if they're not

in a state where they can be fully focused on the task at hand, enter a flow state and do what they need to do, especially when they're learning new tricks, you know, things can go wrong real fast. And, you know, at ACL and you're out for a year, concussion, or your whole career can end overnight if things go really bad. So, We have to look at not just the strength training in my world, but the endurance training, the other activities, the on snow. So when you're just looking at strength training in a silo, I think what you would do is if you see HIV depressed still,

instead of taking another day off, I would modify the train. And what we know is that as far as volume goes, six exercises times three sets for each exercise seems to be, the stimulus at which HRV will start diving and training not to failure is another factor so when you train to failure

HRV is much more affected you create much more fatigue in the system and we've seen this in the velocity based training data you know there's a group out of Spain Gonzales Badiou Perea Blanco there's a bunch of them there that they're big in the velocity based training world, looking at auto-regulation, using speed to auto-regulate your training. So instead of

prescribed reps, you go until the speed gets a certain threshold, you know, 20% velocity loss, we know that's where the metabolites, the ammonia, the lactates start building up and you start creating that residual fatigue from a biochemical standpoint that's going to last to the next day. Whereas if you can keep it under that, then you'll be fine to train day and day out. And the recovery curve happens the same day for the most part. So similar to HRV, what they showed, and it's the same protocol as the VBT, is that if you take an 8RM, so 8, the most amount of weight you can lift 8 times, and instead of doing it 8 times, training to failure, cut it in half, do 4 reps. If you're doing a 6RM, the most weight you can do 6 times,

cut it in half, do 3 reps. And that's a protocol used to optimize for power. if you're doing, if you're training for a task and you want to train for power, but you don't want to create fatigue. So it's a general in-season protocol. If you have no measurement tools, cut your RM in half. Love that. Now, what they showed was that when you do that, there's no changes in HRV from a strength training session.

So there's things we can do that if we don't want to see a big drop in our HRV, keep sets three or less. do no more than six exercises per session, and keep your rest greater than two minutes. And these are things that when you think of strength training, you know, three sets is kind of the go-to. Two-minute's rest. That's about 94% ATP-C-Recovery. Takes about seven minutes to get full recovery, but, you know, we'll take 95 each time. So there's things that are inherently known in the strength training world that most people do naturally and most coaches prescribe. And so just stick with that stuff.

The other one that I would say was one of the biggest game changers in my strength coaching career was training not to failure. And I got under this through Dan John's book, Easy Strength. He's American powerlifting coach. He wrote it, I think, with Pavel Satzueling, kettlebell whizzing, for lack of a better term. And it turned me on to this not to failure. So I started digging into the research. And again, a lot of it was from these Spanish researchers. And basically, when you train not to failure, you see improvements week after week

and you get recovered within the same day. When you measure that key performance indicator lift two hours, four hours, six hours, eight hours, within that same day, they're recovered. So even if you think about a weight session versus your sport training, If you can separate them by six hours, not trained to failure, you're going to be pretty recovered by the time you get on field or on snow for our kids. And the way that I would do this is use that same protocol I suggested. Cut your RM in half.

Or if you want more intensity, leave two reps in the tank. That's the general rule of thumb, two reps in reserve that I've used. So when I was working with a So if eight reps for me If I'm at like Okay, this is my last one I don't go to 10 I stop there

If I go to the next one My technique is going to be compromised Like I'm going to really really feel it Is that how people need to think about it When they're in the moment? Yes and then take two reps off it So instead of doing that eight, do six Gotcha, okay

So you're leaving two high quality reps that you could still compete So two in the 10. Got it. I love that. Okay. Cool. And I like simple heuristics or general rules of thumb because not everyone has measurement tools.

Yeah. So if we can keep things as simple as possible and the rules that athletes and people can remember, it just makes life easier forever. So I think, so what you're kind of saying for athletes and for individuals who aren't competing for a particular sport or discipline, consistency and availability, to strength train trumps any gain you might make kind of lifting to failure. With the caveat of depending on the goal, so there is a caveat here, the caveat being aesthetics, so people training for bodybuilding or aesthetics. So training to failure has two main benefits.

One is muscle size. If you train to failure, you're activating all your motor units, there's some occlusion type effects for hypertrophy, muscle growth, you do need to train to failure. It is a great stimulus. And the second thing training to failure is good for is mental fortitude. How much can you push yourself and fight through? And then you get a spotter and do drop sets or do negatives and do these things that push you beyond. Now, could these techniques be used in the off season for an athlete 100%. And I've had situations where we need to put size on and up. But for the most part, if you want performance and you don't want size, which in my world acrobatts and endurance athletes, most of them don't want to put on

size, the easiest thing you can do, don't train to feel it. Okay. So for the general exerciser who has life, who has a job, who enjoys going to the gym and wants to train more often, probably for health and fitness. If you cannot train to failure, you're going to probably have more beneficial outcomes and feel better every day. With the caveat, if you want big muscles, you're going to have to train to failure. Okay, cool. So, you know, intent, you kind of bring that up. I think it's really important. So if I'm in a looking, just kind of in a maintenance phase, how do you think about novelty? Because I know, I know for me, like when I introduce a new kind of type of kettleball movement or whatever, like my chances of getting sore are kind of

a lot higher than if I'm doing something that my body is used to. So how does novelty impact HRV? And are there any data that around that? Not that I aware of. You know, in the research I've read, haven't seen anything around a new exercise and how it affects it. That'd actually be a great little study. It would be interesting. Yeah. But if we were to say, okay, novelty equals as soreness, maybe just talk about soreness and HRV. Yeah, so, you know, in season, I tend to only choose exercises

that my athletes have done are comfortable with. I try not to introduce new things because when we're in season, our goal is performing. So we still want to make gains. Yeah, but we want to maintain. But given what we've seen in that

soreness doesn't correlate with HRV, it's hard to know. you know, I would speculate you would still see a drop because of the nervous system effect and the low frequency, you know, the spectral side having a change there. So I would speculate that you would see a change from a new exercise versus continuing to do something you're comfortable with. But with the lack of correlation in the research that we've seen with pain and HRV, I don't know. Yeah.

And it's interesting because when we kind of get outside the kind of physiology world and look at the world of psychology and, you know, it's psychophysiology, but it's looking at it through the lens of pain as in, oh my God, my back hurts or pain as in, I have post-traumatic stress as water. There actually is a really strong relationship between pain and heart rate variability suppression and heart variability and decrease in vocal tone and all that. so but it's interesting i find it fascinating that they're the the the muscle soreness the pain that comes with muscle shortness there's no correlation whatsoever it like just fogs my mind and i you know and this was definitely at princeton this is why we you know we had obviously objective measures

to kind of quantify readiness but this is why i always like kept in this objective measure because again there are you know my office like oh shit you know my left ass is like so sore you now my left glute is really sore, but it just didn't show up in any of our kind of objective markers. So asking people how they feel as a practitioner is very, very important, obviously, to get this fuller picture. But where is, maybe talk real quick, kind of where the, where it's going in terms of being able to quantify neuromuscular kind of load and how that might actually, and how can we actually, you know, quantify that in a way where we can use it to modulate our volume and intensity more kind of intentionally?

Yeah, well, this process is very similar. So you have a baseline in some explosive, high strength, high speed task. You know, I'll use the ones I use jump, we use jumps with my skiers. And once you've developed that baseline during a rest period, you look at what is a real change versus natural variation. And then when you're testing, are they inhibited? Like, is there a decrease in that score? And if there is, you look at maybe pulling off some volume of training. I like pulling volume off before pulling intensity, but there would be times where you choose to pull intensity off. And given what we've seen in the HRV research, the volume has the biggest effect,

you know, pulling that off would also create less full body stress. Yeah. Or if they come in that day, and we've seen this, they can come in, they're not feeling great, they don't want to train, you know, they hop on the force plates or put on the accelerometer and they have one of their best jumps ever. And it's like, oh, I'm ready to go today and it actually changes their mindset around, you know, let's get after it. Let's do some extra sets.

let's try to maybe do a PR. Let's try and do something we've never done. Just let's push it. So I think you would use it the same way and almost like a different, you know, speedometer dial on your car. You have your HRV here. And if both are depressed,

that might be the sign. It's a rest day or take time off. Or let's look at focusing on recovery modalities. I would much rather find what they can do. what can we go to yoga? Can we do some breath work? Can we do something that's easy that's going to promote rest and digest and recovery instead of just saying let's take the day off?

Or if both dials are really dialed up, let's go after the heaviest squat you've ever done. Let's try and do something you've never done and really push it. That's so cool. What would you, on the recovery side, you know, what would, what are your kind of go-toes? and I suspect that it's probably very individual because different athletes like different modalities and have different psychological effect on them. But what are just kind of, you mentioned meditation and what are just if you have a suite of kind of tools in your pocket as a coach that you use, which are the ones that you feel

like are most efficacious at helping promote recovery after like big strength sessions? Yeah, this is where a lot of my interest is right now. So one thing for listeners to understand is that extreme sports, they have a high risk component. And they're very outside the box compared to traditional sport. And when you add in the freestyle sports, it's almost they're almost like artists. You know, they don't live inside the box. They paint outside the lines. They don't like being constrained.

So there's a very free flowing, adaptive training that's, Schedules don't really exist. And in an outdoor sport, we're at the whim of the weather. So it's one of those things that you have to be extremely adaptable and extremely flexible with the training and that. Now, because they're very out there outside the box artists, I would say they're more into outside the box training modalities and techniques. I was surprised at how much buy-in we got with meditation and breathwork.

You know, breathwork was one of the things I introduced. Started with box breathing and a couple other techniques we'd do before bed or before competition. And then you introduced me to resonance frequency breathing. And we kind of cycle between a few. You know, I've tried the sigh breathing from Huberman as well. And I do find different athletes like different ones. now we haven't been able to measure what is the exact effect of that breathing that's why I'm really excited for the stress monitor whoop just launched because we can have our athletes look at

their current score which is made up of HRV and HR and then we do the intervention and we can see how much did it actually acutely decrease so we can start to actually figure out which of those techniques is good for each athlete and I think I would add the the caveat in there, too, back with HRV, almost all the research with HRV shows that it's individual, that, you know, there aren't trends for, for sex or BMI or a lot of these things that you have to treat the person as an individual. So with the team, we try to do that as much as possible, not only with HRV, but at the high level sport, there ends of one. So you have to treat them that way. And, you know, the beauty of a tool that's a 24-hour wearable, it's, you know,

treating them as an end of one day after day. Some of the other tools, I teach yoga. So we do yoga because you can combine the breath work. I'll do like a yin style class where we hold a position for three minutes and focusing more on the breathing. And I don't necessarily do the stretching for increased range of motion. If there's a deficit, if we go back to demands capacity, you know, if they don't have a capacity for, say, a certain type of grab while they're in the air, then we need to get that range. But a lot of it is about decreasing muscle tone and getting parasympathetic drive. So we do do stretching and foam rolling and self-massage and a lot of these things that, you know, you can find debates about them all, but I find that they get my

athletes back into a recovery state and they're relaxed and how can we create sympathetic drive as much as possible. In these extreme sports, they're driven into fight or flight. You know, you could die. So if you're doing a sport every day that you could die, obviously they're not pushing the limit that much every day. You're going to be shoved into fight or flight, whether you like it or not. So that's where a lot of the work I'm doing and some of the research I want to go down is how can how much fight or flight do these extreme action sports get into and then what are the best techniques to get them back into rest and digest and this is the area that really interests me right now yeah I think the same you know I think this is an area

you know I work as you know a lot of my research is with the high stakes high stress environments you know with military operators and you know who are in extreme environments and frontline in health care trauma surgeons and acute trauma surgeons. So I definitely see this chronic activation, you know, chronic sympathetic activation in these folks. And we are kind of testing all sorts of different types of modalities to see, you know, and isolate the effect of these modalities to see what these are really the most efficacious at kind of getting them, shifting them, you know, back into this more deactivated kind of breast and digest state. So I share that same passion and interest, you know, I think too, like knowing, you know, how to, what are these things

that activate our nervous system, you know, like a cold plunge, for example, you know, and I think you make a really important point that there's a mindset element to that that makes you feel kind of bulletproof and really accomplished, you know, training to failure sometimes is really good because you just feel like, shit, I did that, you know, and you're proud of yourself. So I think there's understanding that, you know, there are really good forms of stress that can increase our adaptive capacity over time if we believe that those things are helping us, right? If I believe, if I'm doing an ice bath and I don't, and I don't believe it's helping me, then it's probably not going to help me, actually. You know, I think there's these

thing as belief effects that, you know, are really, really powerful and impact the cells in our body and, you know, our physiology. So, so I think there is this, this concept that stress can be very good. And so I suppose how do you think about that in your environment? You know, you like, you know, we're kind of in these environments where there's already inherently a lot of stress. But how do you layer on this kind of hermetic kind of stress on in, and do we even need to when people are already kind of chronically activated? How do we, how do we think about that? Yeah. I mean, I think your demographic, one of the crazy parts is that, you know, we're just playing games on my side. We're doing sport. You know, it's, it's entertaining.

Your demographics is life and death. Yeah, like you're dealing with real people and there's real consequences. I find that even more fascinating, you know, the colleagues I have that are strength coaches and performance directors in military and, you know, that's where the things need to go because they make a big difference. But to answer your question, so when we bring new athletes onto the team, and we usually bring a few every year, the goal right of way. way is to show them how to train. And during our first camp, we get in the gym every day after

skiing no matter what. And it's to create the habit that you can show up here and do something instead of just going home and doing nothing. And if we're doing in a heavy camp, our general rule of thumb is keep your strength session and RPE six or less and leave the gym feeling better than when you showed up. And it takes, all it takes is one camp to get this mindset. adapted and every athlete leaves that first camp understanding oh I can train in the gym every day with skiing because most of the mindset is it's going to interfere with whatever I'm doing whether it's cycling or running skiing but you can do it it's just about finding what's the right dose and make it a recovery dose that makes me feel better and we we see this in the data as well

you know they show up and do a jump test and it's still good or the HRV is still good you know we're not just continually in the red, we're hovering yellow or even in the green. So I think it's changing mindset and just finding the right dose response for the individual that is sustainable day in, day out. I love that. I definitely find that myself, you know, if I'm in a scenario where I've got a red day, it's usually not because of anything that I did physically. It's usually, you know, a psychological thing going on, you know, where I, you know, not managing stress well or, you know, just, you know, tough conversation or, you know, whatever it might be. You know, that's kind of, you know, it's caused some level of rumination. Anyway, I see that manifest in my

hearty variability pretty, pretty much on cue. But I always find that like not going to the gym is probably the worst thing that I could do. Or, you know, I don't really go to a gym. I have my own gym here at home. But I find, but I think, you know, that doing something that is going to, that's active, but that really feels good to me is important, you know, and maybe that's just going for like a long rock, you know, with a 30 pound plate. And, you know, and I just, I don't have any real kind of performance goal in that session. I'm just really trying to get outside of nature and do something that feels good to me that maybe doesn't feel that hard, you know, isn't going to tax me. But I think you make a really important point that, you know, just

lying around and not doing anything is probably not going to be helpful to anyone. So in terms of chifting our mindset and our mental state. So I love that idea of just getting out and doing something and and you know just thinking more intentionally about about the the dosage and and what that activity actually is and making sure it lines up yeah so the athletes that come and and they don't feel like doing a lift or they're they're crushed that day you know they can hop on a bike and do an easy spin whether that's zone two you know it's all the rage right now or you know it's just something that is easy zones or um or they're do a stretch while everyone else is lifting, you know, but you're showing up. You're part of the team

and you're still doing something that benefits. Some days we'll just say, you know what, let's go play spike ball or play beach volleyball. Let's go play a game where you get their mind off training and it's fun, but they're still getting some jumps or some movement. You know, you got to mix it up every now and then. And we do a lot of cross training with other sports. So we'll just try to throw in tennis, basketball, keep it low key, but just have fun play a game. get your mind off it as well. And sometimes that that's all the stimulus they need. Yeah. All my coaches were both collegiate and at the U.S. level were unbelievable in that regard. Like they really had a pulse on when we were like, we just couldn't get it. Just we could not go in the gym on the track or on

the field. And they would just be like, all right, let's play water polo or you know, do something totally random. And we're like, oh, okay. Yeah, they take us whitewater rafting. Like they were just like so good at like recognizing that. And I think that's like such an important. you know, for coaches who are listening, you know, to just be in tune with your athletes, you know, and know when, you know, you can shift the morale by just getting them in a new environment, you know, that doesn't have anything to do with your sport. Like that, that always lifted our team up. And we'd come back and train so much more effectively.

So, yeah, I think that's, that's, and I would imagine if we were measuring it, we'd see positive influence on HRV for sure. All right. So maybe just to recap, Chris, what are the main ways strength training? influences heart rate variability. Yeah, so when you do a strength training session, your heart rate variability will decrease. The more volume you do, there's a dose response.

The more intensity you do, there's a dose response. The less rest you do, there's a dose response. So if you want to train and maintain, so not have a decrease in your HRV, not have overload stress on your system, you know do six exercises or less do three sets or less have two minutes rest or more and don't train to failure those would be the the general guidelines that if you want to train day and day out and not create extra stress and go into overtraining or overreaching that that is sustainable

day and day up perfect well this has been such a fun conversation um I love that. We're able to dig into this. Maybe one final question that I feel like we didn't hit on. Maybe just talk through age and how that influences heart rate variability and what someone might expect when they begin a strength trading program or, you know, is there anything there that is worth mentioning. So looking in the science in the literature, there's a couple trends. And so typically young people have healthy autonomic nervous systems. And we tend to see less effects of a strength training session in younger people.

So the more older someone is, the more chance they have a dysfunction of some kind or some kind of disease state. And we tend to see greater improvement in HRV with those people. So if you do a strength training session and you're young, you may see no acute effect or it may be back to normal within 30 minutes. And that's okay. That's just a sign that you're recovering good and your system's running okay. It's when you get into older people and disease pops where you tend to see more of an effect. Now, even through all of this, the literature shows that resistance training tends to not make long-term changes. in HRV. So if your goal of training is to improve HRV over the long term, resistance training

is probably not your best tool. You know, there's a lot more research around aerobic training and aerobic training for that energy systems training. So just a little caveat there. But for the most part, there isn't a huge effect for age and there isn't a huge effect for sex or BMI or any of the other physical body factors with respect to HRV differences. Cool. After a bout of resistance training. Excellent. Chris, where can folks follow your work?

Yeah, well, you know, I'm working with Wu, so you can find me there. I work with the freestyle ski Canada. You can find us online. And then my own chapy strength on Instagram and Twitter, I don't tend not to use social too much these days. I'm too busy in the trenches kind of head down and not head up, but I always love talking shop as you and I know. If anyone's interested or wants to know more, I'm always happy to connect. Well, we appreciate you so much, Chris, and all the good work that you're bringing to Whoop, and we've got some really special features rolling out soon that I think folks,

to our general, you know, general membership, I think folks are going to really love specifically around strength training. So, so thank you for all your contributions and for your insight today. Thanks for having me. I appreciate it. Big thank you to Chris Chapman for joining the show and sharing his insight on strength training and the impact on HRV. If you enjoyed the episode of the WOOP podcast, please leave a rating or review. Please subscribe to the WOOP podcast. Check us out on social at Woop at Will Ahmed. If you have a question, what's he answered on the podcast, email us, podcast at whoop.com, call us 508-443-4-9-5-2. New members can use the code will.

Get a $60 credit on WOOP accessories. That's WI-L-L. That's a wrap for this week. Thank you all for listening. We've got a very special episode next week as we announce a huge new feature. So look out for that. As always, stay healthy and stay in the green.

Thank you.