WHOOP Podcast - How To Improve Your Heart Rate Variability (HRV)

Episode Date: August 12, 2026

Heart rate variability (HRV) is one of the most powerful metrics for understanding your recovery and resilience. In this week’s episode of the WHOOP Podcast, WHOOP Global Head of Human Performance and Principal Scientist Dr. Kristen Holmes and WHOOP Staff Research Scientist Dr. Greg Grosicki explain what HRV actually measures and what it indicates about the health of your autonomic nervous system. They unpack the biggest factors that influence HRV, including sleep consistency, hydration, training load, psychological stress, alcohol, and illness. You'll learn how to use HRV as a practical guide to balance stress and recovery, identify which habits are helping or hurting your physiology, and make small, consistent lifestyle changes that support better performance, healthier aging, and greater resilience over time.(00:00) Cold Open(00:35) What is Heart Rate Variability (HRV)?(01:48) Why HRV Matters For Recovery(03:20) How WHOOP Measures HRV(04:44) Why You Shouldn’t Compare Your HRV to Others(05:43) Understanding the Autonomic Nervous System(11:28) Why WHOOP Measures HRV During Sleep (12:36) How Your Behaviors Impact HRV(21:30) Impact of Sleep Consistency on HRV(23:19) The Relationship Between High Stress and HRV(26:54) How to Improve Your HRV(30:33) The Habits Negatively Impacting HRV(36:26) Why You Shouldn’t Obsess Over HRV(37:51) HRV-CV: Understanding Weekly HRV Trends(41:49) How HRV Changes Over TimeListen to Our Episode on Heart Rate Variability Coefficient of Variation (HRV-CV)YouTubeSpotifyAppleSupport the showFollow WHOOP:Sign up for WHOOP Advanced LabsTrial WHOOP for Freewww.whoop.comInstagramTikTokYouTubeXFacebookLinkedInFollow Will Ahmed:InstagramXLinkedInFollow Kristen Holmes:InstagramLinkedInFollow Emily Capodilupo:LinkedIn 

If you're wondering why your HRV is just slowly getting worse, it's likely because you're not giving yourself appropriate amounts of rest relative to the stress that you're putting on your body. Yeah. HRV is a reflection of what's going on in our autonomic nervous system. So this comes back to like what you're capable of taking on, right, based on how well you're recovering. Hary variability is one of the inputs to whoop recovery. It's weighted the heaviest because it is so responsive. to so many things in our life, not just training stress, but psychological stress as well. Dr. Gregorsicki.

Welcome back. Yep. Love to be here. Talking about our favorite topic today. Oh, man. Hurry variability. This is very much, I think, the hero metric at Woop has a lot of history. It has been, I think, just an incredible exploration of just the science of the autonomic

nervous system and just understanding it, I think, in where. ways that are practically meaningful for individuals. And I think when, you know, we unpack the metric of heart rate variability, it gives us really good insight into the health and robustness of the autonomic nervous system. Heart rate variability is really a measure of the ANS. So let's talk briefly, like let's do just a quite literal definition of heart rate variability. Yeah. And then we can talk about the autonomic nervous system.

Yeah, I think HRV, your heart rate variability, is perhaps one of the most useful, but also most understood features on any wearable platform. So I think it's super important we're going to do a deep dive into this topic. To start out with, what is HRV? What is heart rate variability? Everyone knows what resting heart rate is. It's the number of times our heart is. is beating in a minute.

And there's the misconception that if our resting heart rate is 60 beats per minute, that the heart is beating perfectly rhythmically once every second. And that's not the case. We know that heart rate speed varies, and one of the factors influencing how quickly or how slowly it's beating is our respiration. This is known as a respiratory sinus arrhythmia, specifically that if we're breathing in and breathing out, heart rate speed is changing. If we breathe in, your heart rate is going to increase. If we breathe out, our heart rate is going to decrease.

Exactly. And so while it might be beating 60 times in that minute, it's not doing so perfectly, rhythmically. That variability in heart rate over the course. of that minute or however long you're measuring it is what heart rate variability is. And so heart rate variability can be, if it's very low, that means the heart is beating very rhythmically. If there's more irregularity between heartbeats or differences in time between heartbeats, then your heart rate variability would be much higher. There's so many different ways to measure heart rate variability in the field. We follow what is the most commonly measured and what is the most

scientifically backed, and that's the root mean square of successive differences are RMSSSD. We do it because that's what the science tells us is going to give us the best insight into all the things we're trying to measure. And there are multiple indices that are used. SDNN, of course. Low frequency, high frequency, but yes. But we use RMSSD because that is the most in sports science. the most known and tested. And for the reasons why we want hurry variability, it's the best indicator, this type of measurement is the best way to give us a proxy understanding of your recovery, which hurry variability is, is really a measure of.

Yeah. And so the number you get for your HRV, most people don't know, but it's actually in milliseconds, and that's milliseconds of variability between your heartbeats. And it can range all the way from, could be one or two milliseconds if you're sick, and it can go all the way up to, I mean, it's very individual, but it can go all the way up to two or 300 milliseconds. Now, most people are probably hovering in the somewhere between 20 and 150, maybe 20 to 150 millisecond range for that heart rate variability measure. But I think one of the things that we just need to clear the air and make abundantly clear is that the biggest possible

mistake you can make with heart rate variability is comparing your heart rate variability to someone else's. Where heart rate variability is most useful is reflecting on what your heart rate variability looks like today or in the past week compared to your historic heart rate variability. And that's simply explained by the fact that genetics can explain up to half and maybe even three quarters of what someone's heart rate variability is. And so so many people, into the trap of, well, how can I make my heart rate variability like his and like hers? And while it's good to have aspirations, chasing someone else's heart rate variability, or if my heart rate variability average is around 60, trying to get to that of my wife's

who's 120 and we know she's always going to be better than me anyway, is a fool's errand. It's not going to happen. Right. And it's such an important call out. So as you have outlined, hearty variability is a function of the heart, but it actually originates in the autonomic nervous system. Yep. Right.

And you've got two branches of the autonomic nervous system, the parasympathetic and sympathetic. And they're both competing to send signals to the heart. Yep. When you are highly recovered, your heart is responsive to both branches in an appropriate way. Mm-hmm. When you are underrecovered, so underslept, under-fueled, over-fueled, dehydrated, you've got a fever, you've just encountered altitude. You know, all of these things are going to basically put your autonomic nervous system. in a scenario where your heart is actually,

it'll put your heart in a scenario where it's actually less responsive to meet the demands of the autonomic nervous system. And this is basically a suppressed autonomic nervous system, which would be reflected as a lower heart rate variability. Yep. Really, any time you're stressing your body, so if we were looking at HRV in real time,

if I'm exercising, my heart variability is gonna be lower, right? Because it should be. That is a highly functional adaptive thing that our body does automatically. It's going to suppress the HRV so it can basically marshal resources to do to actually meet the demands of the exercise. So I think at a base level, just understanding that any stress that we're encountering over

the course of the day is going to suppress our hearty variability. And that's why I think it becomes really important to think about the stress that you're incurring across the day in the context of rest. You want to make sure that the stress that you're putting on your body is met with appropriate levels of rest. And that's really when we think about positive adaptation, that's really the path, is just making sure that we're kind of appropriately toggling between stress and rest over the course of the day. Yeah. Knowing that we want to give our autonomic nervous system a chance to just rest, right?

If we're just stress, stress, stress, stress, that eventually will come back to haunt us. Yeah. Right. And will be reflected in a lower HRV over time. If you're wondering why your HRV is just slowly getting worse, it's likely because you're not giving yourself appropriate amounts of rest relative to the stress that you're putting on your body. Yeah.

So this comes back to like strain coach and, you know, listening to recovery, right? And strain coach is going to basically tell you what you're capable of taking on, right, based on how well you're recovering. And that's why it's just such an effective tool, right? And HR gives us just this proxy understanding of how you're adapting to all the strain that you're putting on your body. And of course, hurry variability is one of the inputs to whoop recovery. It's weighted the heaviest because it is so responsive to so many things in our life,

not just training stress, but psychological stress as well. It is a psychophysiological mirror. Yep. Yep. I feel like that's a decent primer for just like what is hurry variability is quite literally, the variability between heartbeats. It's not a metrodome. We want high variability means that we are really capable of responding and adapting to stress in a super functional way. Low variability means that, okay, we need to rest.

We need to give ourselves a chance to recover potentially. A suppressed HRV is appropriate in certain context. but if we're waking up with a low or suppressed HRV chronically, that means we probably need to give ourselves a little bit more time to rest. Is that fair? Yeah, no, I'd say that's exactly right. And I'd say, you know, just to touch on one point that you hit on, that HRV is a reflection of what's going on in our autonomic nervous system.

And so just to kind of even take a step back from that, right, our nervous system consists of two branches. We got our central nervous system, which is our brain and spinal cord, and then our peripheral nervous system, which has two more branches. And those are... Somatic and autonomic. Somatic and autonomic. Perfect.

Just like you said, yeah. And the somatic branch of the peripheral nervous system, these are things that are under conscious control. So that would be the way in which if I wanted to get up and walk across the room to get a drink of water, I would consciously make that decision. And through my nervous system, I would communicate with the muscles to contract and stand up. and go get the drink of water. The autonomic branch of the peripheral nervous system, the way I would always explain this in teaching,

was this is the automatic things that our body does that we're not even thinking about. Regulating blood pressure and temperature and heart rate. And it's light outside and my pupils constrict and digesting my food. And so what is so neat about heart rate variability is it's capturing what's going on with all of those autonomic processes in our body.

and then even furthermore in the autonomic nervous system, just like you said, we have our parasympathetic and then our sympathetic branches. And just to make those a little bit more digestible, the parasympathetic branch of the autonomic nervous system, this is the one associated with the processes of rest and digest, whereas the sympathetic branch, this is the commonly known as fight or flight branch of our autonomic nervous system, right? And so heart rate variability at its essence is reflecting the current physiological state of our autonomic nervous system. Are we more in the state of rest and digest or fight or flight? And whoop very intentionally measures heart rate variability nocturnally

at night. And that's not necessarily the same across all wearables. I think we have very strong rationale for measuring heart rate variability nocturnally for a variety of reasons. One, we know that by measuring heart rate variability when people are asleep, again, thinking about we're trying to measure the balance between parasympathetic and sympathetic activity or rest and digest and fight or flight, if we're measuring it during sleep, we're always measuring it at the same time. So there's no confound by if we're just measuring heart rate variability throughout the day. Right.

Because it changes. You could have a drink of water. Your HRV is going to change. You could be, you just have run up the stairs. Your HIV is going to change. You could have a hard conversation with a colleague. Atrophy's going to change. Like it just, there's, it's really non-specific, which makes it, which is kind of its

blessing and curse in some ways, you know, but I would say more blessing than not, right? Yep. The, I think the problem with it being nonspecific is you can't always pinpoint exactly what moves your HRV because a lot of things move your HRV. Yeah. But some things that we know are very. very predictably move your HRV are things like sleep quality. Inconsistent sleep, right, is going to reduce your hearty variability.

Drinking alcohol is going to reduce your hearty variability. Being hydrated will increase your hearty variability. Managing stress and rest appropriately is going to increase your hearty variability over time. So we know very clearly from our data, certainly, and from all the external research that has been done by, you know, our collaborators and other folks in the field, you know, we have a really good idea of how to improve HRV over time or how to maintain a robust autonomic nervous system, which really is, I think, you know, there's this paper we were just talking about that came out, this theory of aging, right? And like looking at the deregulation of the autonomic nervous

system as a basis of or a hallmark of aging, which I thought was a really, it's just an opinion piece that was just published in December of 2025. But I found it just, It definitely feels right to me in that just seeing the power of having a regulated nervous system and having a robust autonomic system as a path to slow the pace of aging. I think there's something really compelling there. And what's great is we can measure it. You can see your HRV, right? You can see how you're living and whether or not how you're living,

the behaviors that you engage in are supportive. of your autonomic nervous system, i.e. increasing your heart rate variability, or detracting from the health of your autonomic nervous system, i.e. decreasing your heart rate variability. Yeah, yeah. And I think you had a great example that was on Instagram a couple of weeks ago or a couple months ago now, where you can think of heart rate variability like a bank, right? And they're the HRV promoting behaviors, and that's like putting currency in the bank. And so I'm totally stealing this from you, but thank you. It sounds very smart. I think it's a super important point that people need to be thinking about, right?

That you can do behaviors that are putting money in the bank or raising one's personal HRV, just like you said, exercise, particularly... With appropriate rest. With appropriate rest, right? And there's a whole bunch of minutia behind what's going to happen the next day after you do exercise. One thing I think any member will immediately realize is that if exercise is done on a given day and it's a fairly low intensity, relative low intensity, that your HRV the next day is likely to be a bit higher.

But high intensity exercise does and should detract from next day HRV. And Paul Larson and Dan Clues have showed that. That's a very good thing. And our data, and just like the paper you were talking about, now very clearly show time and time again that healthier physiological profiles exhibit changes in HRV that are commensurate with their health status. Specifically, very interestingly, and I was woefully ignorant to this when we started the alcohol

studies that we published in Plus Digital, I assumed that, well, now that I'm getting older and I have a couple drinks, my head hurts more the next day than when I was 20. And so going into that study, I suspected, well, maybe older adults are showing this through greater responses in HRV. And I could not have been more wrong. As a matter of fact, it's younger adults who have far greater age. HRV responses. And that's a sign that their physiological system is responding appropriately to the toxins as a healthy autonomic nervous system. If you are able to drink four drinks a couple hours

before bed and you have no real change in your HRV, that is not a good thing. Right. And there's lab data showing this again in clinical populations mirroring the findings that we're showing in thousands of people and millions of days in the real world in the lab, looking at things like blood pressure and cardiovascular reactivity to different laboratory stressors. My favorite one was one we'd do called the cold presser test, which essentially we'd fill up a lunchbox with water and ice, and then put someone's hand in it and look at how their blood pressure. And older adults, sometimes they will not have the cardiovascular reactivity of a younger person. And that's, that's undesirable. And so I think to be abundantly clear, if you do a high intensity exercise one

day and your HRV goes down the next day. That's not something to be concerned about because again, long-term trajectories of fitness aren't made on a single day. Your HRV responding to something, just like the paper you were talking about. And even there's an older paper by Lou Lipset that Israel down the street. 1992. Yeah. And I think it has almost 2,000 citations. Talking again about a hallmark of aging is a healthy physiological response. And that's mirrored in our data by these HRV responses. And so... That was such a cool insight.

And validated everything. You know, just a lot of the things that I think have surfaced in the literature and just the evidence around what is healthy versus not, you know, to kind of see that very clearly in our data. And it was really neat. Yeah. It just explains a lot, you know, because people are like, oh, yeah, I'm like, I can drink because it doesn't matter.

Like, I'm not getting any response. Any change in my HRV? I'm like, ooh. Yeah. That's not a good thing. And it's the other end of the spectrum, too. And we show this in exercise training data that unfortunately people who are older, their HRV doesn't go up as much when they start doing training.

People who are less healthy, their HRV doesn't show the same benefits. And so HRV plasticity or this cardiovascular dynamic range is a good thing. And when that becomes compressed, that's a sign of not as good health. So I think for younger folks, you know, just preserving. your autonomic health obviously is really important. And certainly for folks who are older, like engaging behaviors that are going to support your autonomic nervous system health is really one of the ways to slow pace of aging. Now, a lot of this HRV research, you know, while it's been around for hundreds of years, really, and, you know, from 1700s, people

know about HRV. Yeah. So it dates way back. But I think in terms of modern research, you know, we're talking 40, 50, 60 years where there's been, you know, clear evidence that there's this very important link. That said, we don't have a lot of good HRV and longevity data. But we know that, you know, HRV, of course, is a proxy measure of the functioning, the health and functioning of the autonomic nervous system. So engaging behaviors that build autonomic nervous system resilience is really everything. And this is the thesis of my book. Let's get the elephant out of room because we hear this all the time. Why is HRV not in? Health span. Why is it not a component of whoop age? Because we don't have the data that links it to all

cause mortality. Yeah. And I think that that data doesn't exist. I think HRV is a intra-individual characteristic. I don't think that we're ever going to be able to say that two people who are 40 years of age and one has an HRV of 40 and the other has an HRV of 80. Between person, data is just not there. I agree. And so a lot of people are pushing, why is an HRV and health span? Why is it in whoop age? It's not there it's intentional and it's not going to be because it again goes back to our original point of HRV is something you should focus on within yourself. It doesn't mean it doesn't matter for health span. But it's it but to your point, you look at it as an individual, you know, and basically

whatever my HRV is today is what I work off of. And I'm trying to live in a way that appropriately, you know, reduces my HRV with the right kind of, you know, exercise and stressors, hormitic stressors, right? I'm not talking about things like alcohol and, like, that's not the path to improving, that's not the kind of stressor that's going to improve your HRV, right? So it's, it's things like exercise, it's things like potentially very time restricted eating, you know, where you're engaging in 12, you know, you're eating for 12 hours, ideally during the daylight hours and you're off for 12 hours. Like that's, that introduces that 12 hour fast introduces a hormetic stress that is very

adaptive and positive for the arm nervous system. Obviously, maintaining hydration status, giving yourself if you are going into altitude, making sure that you're really thinking proactively about how to kind of regain homeostasis, you know, at altitude, right? Because that puts a huge stress on the body. But if you can manage that stressor proactively, when you come back down from altitude, that actually you're going to get some positive adaptation from that. So there's a way of, I think, living that will, and obviously sleep and getting quality, consistent quality sleep is a path to improving your heart. So how long, Kristen, have you been tracking your HRV, would you say? I mean, I was using a mega wave like

16 years ago. 15 years ago. Yeah, so first be, yeah, so very long time. So thinking about your HRV tracking, HRV journey, I think very worthwhile. I'm curious, is there any particular thing that you've learned, particularly about your behaviors, that may be surprised you? Like, oh, I didn't know this would influence my HRV in this way. So my most consistent measure, of course, has been on WOOP, right, in terms of like the timing, because when I was using First Speed Omega Wave, I was basically doing a daytime reading. Yeah. Right? So five minutes, using the last three minutes to actually get my measurement. I would say in the last 10 years, you know, I, when I came onto the WOOP platform, my, my HRV was 60

milliseconds. Oh, wow. Maybe there's hope for me after all. You know, now I'm, you know, in the hundreds, right? So I've been able to improve and modify my HRV just by looking just to see what are the behaviors that seem to move around my HRV the most. And I would say sleepway consistency was the biggest unlock for me. Yeah.

Because that seemed to have a cascade of, I think, kind of second and third order effects that I didn't anticipate, right, in terms of just hormone balance, like hunger, you know, my hunger hormones seem to just be more predictable in terms of like I should feel hungry. I feel hungry when I should feel hungry. I'm full when I should feel full. Like those just seem to work better. I was able to just feel, you know, I just alert during the day in ways that are really, feel really functional and good. I'm able to sleep when I need to sleep.

I get quality sleep. It was another big unlock from sleepway consistency. Seems to drive my sleep quality, which we know in the literature, sleep quality is literally correlated with heart rate variability. It's the only aspect of sleep that is, which is interesting. In the external literature, I think we see differences in the data. Sometimes sleepway consistency seems to correlate and otherwise at times it doesn't. It's interesting. And I think, too, just like more isn't better. And I will say that the other huge piece is when I am under psychological duress or, you know, just obviously our relationships change, like we have hard moments, you know, and just parenting. And, you

I will say when I am psychologically stressed, that crushes my HRV. I'm very sensitive to that. Yeah, you touched on it earlier, and I think it's such a good point in that when we think about HRV, the biggest advantage is also its biggest weakness. And that's that HRV will pick up on just about anything. It could be travel. It could be hydration. It could be the amount of exercise you did.

It could be the temperature of your bedroom, whether or not your curtains. Oh, that's another one. Damn. Yeah. It could be what you had for dinner. And that I think one of the maybe most important things, and one of the things that I think whoop can actually help folks with. And there's some new features with a journal that I absolutely adore that I want to talk

about here, is helping members make sense of the behaviors that are improving their HRV. And I think when anyone adopts a wearable, hopefully whoop, I think it's such an important point that members work with the device and AI coach in particular is excellent at this. It's gotten so good. To help put clarity to the confusion. So my HRV is going up. My HRV is going down. Well, what are the journal behaviors that you're logging? For me, a huge unlock was actually realizing the benefits that come from taking magnesium before I go to sleep. And I was shocked. But when I started doing it, my HRV went up about 10 milliseconds.

And I was doing personalized experiments of I would stop because I didn't believe the data at first. I took it and it went up. And then I would not take it for a little while. But I'm outside. I'm exercising, particularly in the heat. And we were talking about our colleagues at UCLA about this just yesterday. And so we're doing an epic magnesium study.

I'm pretty pumped about this. Yeah. And I noticed that actually in the summer, I need more of it than I do in the winter. And if in the winter I can actually take maybe a little bit too much, in which case I'm waking up during the night. Yeah. But so I've actually learned that there's a seasonality to my magnesium need rhythms. And that's entirely come from Woop Coach and from tracking my behaviors. And one of the things I love now that I actually was unaware of until recently is that previously the insights we got from our journal behaviors were just, what is the recovery?

impact of a particular behavior. Did I take magnesium? Did I take caffeine? And the caffeine one is one that, frankly, I never filled out before because what day do I not have caffeine? But now I've learned that the journal will actually give you insights in regards to quantity and time of day, which is huge. So members can set up these personalized experiments in the app with themselves and of

one studies of now I put how many cups of caffeine and when was the last time I took it. I can put how much magnesium I have. And when they click on the behavior insight coming from any of the journal behaviors they're tracking, they get insights into what is the recovery impact of that particular behavior as well as the potential for dose response effects and time of day effects. When you're running those personal experiments, how do you limit some of the confounders, right? Like, you know, which obviously is hard to do. But I think if you're doing like magnesium, for example, like you want to isolate the effect. the best that you can.

So maybe taking Ashwaganda, Lions Main, and you know, you want to like maybe separate it out. Yeah. Yeah. I don't know. This is one my wife is on me about all the time. How do you know it's that? And, you know, I'll be like sharing with her some insights that I'm like real excited

about. But anyway, I think I think the biggest one is trying to only manipulate one thing at a time. Right. Right. And then also doing, you know, some on, some off, some on and then just looking for those, you know, those response effects. Yeah. You bring up a really good point.

You know, I think when you're, like when you think about advanced labs might also help folks understand where they might have some of these deficiencies. You know, like just in the summer you're deficient of magnesium, for example, like, you know, maybe some times of the year you're good with vitamin D. Other times the year you're not, you know, maybe summer versus winter. That could have an impact on your heart variability, right, in ways that are potentially meaningful. So getting the blood work done, I think, a couple times a year is probably really important. I like the kind of December-July cadence. That way you're getting winter and summer, which we know plays a huge role in these. Seasonal effects are massive, right?

And you're working on a paper right now that looks at seasonality and, you know, from a couple different lenses. And yeah, I mean, I think that that's important for folks to consider, you know, what the summer months working out and training does, right? And if you're trying to, you know, maintain cardiovascular fitness and improve heart cardiovascular fitness, some of these like small what seem like small things actually do compound right and either are helping are favorable to your training adaptations and just life load adaptations or not right so yeah I mean that's where I think these data are like wildly insightful and valuable right because you can

course correct and you can you know I don't even want to say optimize but you know you just can you know you're just able to live your values you know we're doing energy and peace right at the end of the day yeah so let's talk about I think something that would be important if we're talking about HRV would be non-modifiable and modifiable factors. And I'll start with the ones that are non-modifiable. There are things that we can't control that are going to tell us what our HRV is. They're going to explain a large part of what our HRV is. The first one, and we already touched on it briefly, is genetics. Yeah. So if you don't like your HRV, the first thing you might want to do, call your parents. It's their fault. You can chew them out. Genetic factors are going to

have a massive influence on HRV. Socioeconomic factors. Yeah. Childhood trauma. Yep. Yep. Yep. Yep.

And other, I think, really, really important, a non-modifiable factor is age. And so sometimes we see, and I'll hear people, it's like, oh, well, you know, I had, and I see, you know, I can't stop but looking on LinkedIn. I had a wearable for a year. I learned all I needed to learn. And then, you know, I've, like, learned how my behaviors. And, you know, I think that's great that people had wearables. for a year. But one of the things we know that is the biggest predictor of HRV, particularly within

people, is their age. And your HRV is going to decline with age. And I believe it was data from Bill Vaughan Hippel right that showed between 20 to 60 years of age. HRV is going down almost 20% a decade. That's a lot. That's so much. And we're going to be soon working on a project looking at ways to offset that with lifestyle factors. So do you want to talk maybe about just lifestyle factors that we know are going to be the biggest detractors and then the biggest boosters of HRV. I mean, the biggest detractors we know are, I mean, just illness, right? And that's transient potentially, but, you know, it does.

If you, if you're chronically getting sick, you're just basically, your HRV is just declining, right? And it's hard to kind of get back up after, you know, multiple bouts of sickness. So illness is a big factor. So I would argue that a lot of the things that we talk, a lot of the behaviors that we're going to talk about that promote recovery in HRV is, you know, those, you just want to be doing those as often as you can, right? To basically create a scenario where your arm nervous system is robust enough where you're not actually so vulnerable that you're getting sick. Yeah. And then real quick, I have to stop you there because one of the things we see in the data time and time again is that before people actually and members talk about this all the time, before they actually begin to feel any symptoms of sickness,

HRV starts going down. And so I think illness is a huge detractor of HRV. You're exactly right. And I think from an actionable perspective, if you see your HRV, you don't know. It hasn't been training. You didn't have a bunch of beers and it's starting to go down. I think laying off the training, maybe focusing on a really healthy diet would be a very evidence-based energy.

Lots of water, maybe a little extra dose of vitamin C. Yeah. I definitely, like when I start to feel like, hmm, I feel a little off. And I get those signals in the data, I do the same thing. And I've been really able to stave off illness, I think, because I can see those perturbations and these deviations. And I really action them religiously. That definitely, like, your body rewards you, you know, when I think you're proactive like that. But yeah, illness.

Obviously, we see just fever in particular. And obviously, low respiratory tract infections, you know, just have a huge hit on HRV. So that obviously is pretty intuitive and it sounds is kind of no duh alcohol, another one, you know, a member favorite, you know, we just, that is the most HRV suppressing behavior that you can engage in is putting toxins in your body. Similar, I think, affect tobacco. Also, when folks are not engaging in tobacco consumption, then engage in tobacco consumption, we see a dilterious effect on markers of resting physiology, in particular HRV.

So tobacco for sure. I don't know if we have lots of data on recreational drugs, but I would venture to guess there's probably a negative impact on any sort of recreational drug, you know, on your autonomic nervous system is not going to like that, right? So any toxin, you know, that we're not really meant to be ingesting is going to have a negative impact. I would say probably, now, I'm hesitant to say this, but I think we probably over supplement as a society, right? You know, you should only really be supplementing. The magnesium case is not to end all, not, no, but that you were deficient, though. Like that's, and I think that's where the blood work is really helpful in that we don't want to be introducing super physiological levels of anything in our body, right? And I, because I think that all, that creates at a cellular level, like just a lot of imbalance and your body ends up having to work harder.

Like you're creating more communication that's necessary between the cells, right? which can't be good. So I think dosing appropriately, knowing where your deficiencies actually are, and only introducing compounds to your body that are necessary is important. Definitely. I would say, you know, I wouldn't say a majority of the people on our platform are overtraining per se, but I think overtraining is absolutely one way to... One of the my best ways to have a good recovery is just to take a day off.

I know, I know. And that's also like an unlock with these data is that I was absolutely over training, you know, doing too much, right? And I noticed like when I listen to strain coach, I actually, I am able to, you know, my training is better. You know, my hard efforts are better, right? I have more capacity to deliver the intensity that I am actually intending to deliver. And I think that's, that's again, the beauty of, I think, the strain recovery relationship.

and coaching. So overtraining is another big one. Dehydration is, I think, right at the top in terms of a negative impact of heart variability. And likewise, hydration is one of the biggest green flags we see. Totally, totally. Totally. Short sleep is another one that is obviously, you know, going to impact heart variability negatively. Now, I will say sometimes short sleep, but really like highly, highly efficient sleep.

our algorithm seems to deal with that a little bit differently. It could be, yeah, it could be, you know, I think that sometimes you could have short sleep, high quality, the algorithm goes back in. Cherry's picks the time points of, you know, to basically calculate HRV and recovery. And sometimes I think we get high recovery on short sleep, which feels a little counterintuitive to our members. But I think that maybe the one way to consider that is that it's, It's a cumulative scenario.

It's not necessarily just that day, right? Your physiology is, it's building on itself, right? Like in ways that are either supportive or not. So I think sometimes, like, just one day of short sleep, for example, doesn't necessarily mean that you're going to have a bad recovery if all other things are good. And, you know, so I think just, you know, I know that that creates some confusion. But I would take quality sleep is absolutely. you know, highly correlated with hearty variability.

And the more quality sleep that you get, the better you're going to recover from the load that you put on your body and likely the more capacity you'll have the next day to live your life at the intensity that you desire. Yeah. I think you make such a good point right there about the value of tracking heart rate variability continuously and daily, but the also critical importance of not over-indexing on it.

Yeah. And we being in this space have all seen or heard of this concept of orthosomnia, where it's where people become, you know, hyper-fixated on their sleep or HRV. We'll just call it out. It's the elephant in the room, and it does happen. And I think it speaks to the importance of one being active connoisseurs of our data,

but also the importance of not over-indexing on any given day. And so I think to take it back to the analogy that you creatively came up with, with HRV basically representing a bank, right? And you can put practice behaviors that are putting money in the bank and then practice behaviors or do behaviors, the naughty behaviors that are taking money out of the bank, right? That if I'm trying to save a bunch of money by the end of the year, the amount of money that I have at the end of the year is probably not going to be overly determined by any given day. Yeah.

And there's a lot of compelling. literature from training adaptation perspective that shows exactly that, that adaptations are more likely to be represented by weekly HRV compared to single day. And then our own data on HRV-CV shows that perhaps what matters even more than a single HRV score. And just for those who may not have caught this episode, HRV-CV representing basically how stable HRV is or the heart rate variability coefficient of variation, meaning you're waking up with similar HRV values day in and day out, and the value of that HRV stability or that HRV consistency.

So you want less day-to-day variation in your HRV is a lower HRV CV, which is an indicator of positive adaptation over the course of a seven-day period. Right, right. And our data, as well as the data from our colleagues collectively make it very clear that the taking it back to the bank analogy, the way to optimally put money away at the end of the year isn't coming from being hyper-fixated on single-day values. And it's coming from looking at the amount we save on a weekly basis. Now, if I'm thinking about that, then what is the value of the single day? Well, obviously every single day matters because if you're not focusing on a single day, then it's like, well, I'll just spend too much money this day.

And it's like, I'll just spend too much money this day. Or from the perspective of weight loss, right? Weight loss is ultimately going to be mediated by someone eating less calories than they burn. And so how much weight you lose is going to be determined by, well, have you eaten less calories than you've burned over a fixed period of time? Now, a single day isn't necessarily going to ruin that. but if you don't focus on every single day, oh, I ate too many calories this day, ate too many calories this day, then quickly you're going to fall down the slippery of slope

of like, okay, well, now it's been 14 days. And I was focusing on the 14-day value, but I didn't focus on any single given day, and I turned out I actually ate more than I burned every single day. And so when we're thinking about HRV, yes, your weekly trends probably matter far more than the single-day values, but that doesn't belittle the importance of the single day value because if you're not paying attention to those single day values, it's very easy to fall down the slippery slope of, well, you've gotten 14 days and you've had alcohol and stayed up too late playing video games every single night. It just those like really acute moments are like an opportunity to course correct.

You know, it's like, and I think too, like, I mean, I say this a lot and I'm lucky I'm still on this path, but you know, I haven't gotten sick in a really long time. And I think a lot of that is just like when I see these big deviations from my baseline, a big increase in resting heart rate decrease in heart rate variability. I'm like, whoa, my body isn't responding to whatever I've done over the last few days. Right. So I just need to think differently about my day to day. Right. And I do that. And it kind of works. It gives you these acute readings that are, you know, kind of egregious deviations from your baseline are just moments to like just reflect and reassess and just adapt your behavior so you, you know,

you can basically essentially just rest, right, is what your body probably needs, and it needs healthy food. I mean, abstaining from alcohol, you know, all these things that we know are going to either continue to push me over the edge, which eventually leads to, like, sickness or disease or illness or whatever, or even injury, or I can kind of pull back and course correct and maybe avoid all of that altogether. Yep, yep. And obviously, like you were saying, some days you may have a really high HRV and

You're just not feeling very good. Right. And other days, you may feel excellent and you have a really low HRV. And it's important to realize that your ultimate state is not going to be determined by any one of those in isolation. That it's important to consider all of those factors and we're deciding and making our decisions. Okay. So we talked about all the tractors. Obviously, if you're doing the opposite of those things, those are the behaviors that promote heart variability and autonomic nervous system health.

But I think for our listeners, you know, and our members on our platform, people are interested in HRV. I think the one great takeaway is that it is actually modifiable, right? And it will move slowly, though, you know, by the, you know, in terms of like HRV new baseline sticking, take some time. And patience and just consistently, you know, you don't have to be perfect, but just in general, minding these behaviors that we know we're going to move around your heart. heart re-variability the most, right? And the reward is like being able to respond and adapt to your environment in a more kind of functional way. And I think that is, that's the promise, you know, of improving HRV. Yeah. Yeah. I think it serves as this beautiful flagpost that we can all look at and assess the impact of our lifestyle on our current physiological state, as well as the way that

our physiology is heading. Yeah. And so it provides, you know, just this daily measure, of where we're at and where we're going. And it can be super useful for whether or not we're trying to run the Boston Marathon or live to be 95. Yeah. The inputs serving me or not. Exactly. A true of you will pick it up.

Whether you like it or not. Yeah. Yeah. No, for sure. Awesome. Well, thank you so much. Great. This is super fun.

Appreciate it. Okay.