Know Your Physio

Kristen Holmes, PhD(c): The Pursuit of Excellence - Convergence of Athletic Prowess, Mastering Sleep, HRV Insights, Women's Sports Health

• Kristen Holmes • Episode 105

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In this enlightening episode, I'm excited to welcome Kristen Holmes, Vice President of Performance Science at WHOOP and a distinguished figure in the realm of sports performance. With an exceptional background as an elite athlete and a coach, combined with her academic pursuits in psychology and sports performance, Kristen brings a profound depth of knowledge and experience to the forefront of athletic science and health optimization.

Our conversation with Kristen is an exploration into the confluence of sleep, heart rate variability (HRV), and women's health in the arena of sports performance. Kristen provides an insightful look into how sleep quality critically influences athletic capability, delving into the nuances of HRV and its importance in determining an athlete's readiness and recovery. As a trailblazer in women's sports health, she illuminates the unique physiological aspects of female athletes, advocating for a more tailored and informed approach in their training and development.

This episode is a treasure trove of wisdom for anyone interested in the science of peak performance, offering a rare glimpse into the strategies that can transform athletic potential. Whether you are a budding athlete, a professional coach, or simply a health and sports enthusiast, Kristen's expertise and insights provide a compelling and transformative perspective. Tune in to this captivating episode and embark on a journey to uncover the secrets of sports success through the lenses of sleep, HRV, and women's health.

Key Points From This Episode:

How to Optimize Sleep Efficiency While Traveling Across Time Zones? [00:13:58]
Why Understanding Menstrual Cycles is Important for Women? [00:24:18]
What Can Women Expect from the Woop Platform in Terms of Unique Physiology? [00:32:26]
How Can Data Help Achieve Deep Bodily Awareness and Intuition? [00:35:59]
Can Training on High HRV Days Lead to Better Performance? [00:41:51]
How to Modify HRV in the Moment to Reduce Stress? [00:44:08]
What Are Some Low-Hanging Fruit Behaviors to Reduce Chronic Stress? [00:47:24]
Why Reducing Stress is Important by Aligning Behaviors with Natural Circadian Rhythms? [00:52:38]
Why is Having an Earlier Meal Important for Better Sleep? [00:53:11]
What Benefits Do Exogenous Ketones Offer for Sleep and Recovery? [00:55:19]


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People

  1. Kristen Holmes
  2. "Stacey Sims"

Books and References

  1. "The Science of Sleep"
  2. "Women's Health and Physiology"
  3. "Circadian Rhythms"

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Kristen Holmes: The data is there for us. You're spending, yeah, nine hours in bed, but you've got 40 disturbances. Like, what's going on? Women have been left out of research. We don't know as much about female body. Women have basically been treated like small men. Sleep was kind of the greatest natural performance enhancer that we have, right? I think that people have a lot more agency than they think. I think just that mindset that, you know what, like there's a lot of things that I can choose. on a day-to-day basis that are going to enable me to perform at a level that I feel really good about. Yeah, performance is a choice.
Andres Preschel: There is only one supplement that I think almost everyone on this planet should be taking, and that's a full-spectrum and highly bioavailable magnesium supplement. Because, well, let's face it, ever since the industrial revolution, our soil has been depleted of magnesium, and therefore our food is depleted of magnesium. And on top of that, Our modern environments, which are inherently overstimulating and stressful, are constantly depleting our body of magnesium. And unlike other nutrients, this is not something that your body can produce on its own. It literally needs to get it from the diet. And one individual kind of magnesium alone is not enough. You actually need seven different kinds to support over 300 biochemical reactions that help regulate your nervous system, red blood cell production, energy production, So, the folks at BiOptimizers have made it very easy and convenient to add back in what the modern world leaves out. They've created Magnesium Breakthrough. Now, I've been taking this for the past two years. benefits that I've seen are related to my evening wind down sessions and my sleep. I tend to be pretty overactive in the evenings, just totally overthinking everything that I do. And this has helped me wind down and get more restorative, more efficient sleep. So I wake up feeling Way more refreshed, more energized, more clear, more ready for the day. And the way that I see it, sleep is upstream of essentially every other health and wellness related habit and decision. Because if you're sleeping better, automatically you're going to have more regular cravings, you're going to have higher insulin sensitivity, you can derive more of all these inputs like fitness, right? You make more gains, you gain more muscle, you burn more calories. And you wake up feeling refreshed so that you can do it again and again and again. And then beyond the fitness, you have more energy to go for a walk, to do fun activities with friends. You are less stressed, so you can socialize anxiety free. And you're also going to be retaining, refreshing and refining your skills and information much, much better. So you won't forget any names. And, yeah, I mean, like I said, over 300 chemical processes that you're supporting with magnesium. And sleep, I mean, wow. Better sleep is just a better life in general. So, I found that extremely helpful on a personal level, and I'm sure that you guys will find it helpful too. Your mind and body, and maybe even your spirit will thank you. So anyway, if you want to get a sweet little discount off of this amazing, amazing magnesium supplement from Bioptimizers, all you have to do is visit the show notes. So you scroll down right now, takes just a couple seconds and boom, you'll have access to all seven different kinds of magnesium that your body needs. All you have to do is hit the link and use code KYP from Know Your Physio. KYP. That's all. Enjoy 10 to 22% off depending on the package you choose, whether or not you subscribe. I'm obviously subscribed because I don't even want to think about whether or not I'm going to get this essential supplement in the mail. And yeah, hope you guys enjoy that awesome stuff. And that's all for now. I'll see you guys on the show. Okay, I'm here with Kristen on the NeuroPhysio podcast. I just want to say first and foremost, thank you for taking the time and for reading up on me, my background and what we're accomplishing through NeuroPhysio. Thank you for your work and your passion and everything that you do. And before we jump into exactly what you do and how to develop mental and physical resilience, would you mind sharing with me and my audience why you do what you do?

Kristen Holmes: why I do what I do. Well, I'm really interested in impacting health at scale. You know, so I think the, I think my whole life I've been really interested in these questions around, you know, how does our mind and our body interact to promote optimal performance, you know, and not necessarily, you know, I think folks are like, maybe hear performance and they're like, oh, performance. But I think, you know, I kind of define it as our capacity to intentionally behave at a level equal to our physical, mental, and emotional potential. So I think that's, you know, very aspirational, but I think that that's really what I've been trying to understand my entire academic and applied career in coaching is, how do we help folks understand what are the actual influences that impact our ability to show up as consistently as possible to be able to access their potential as a human being? That's really That's really my life's work, I suppose, and why my calling is to try to help people understand how to apply their effort so they can take control over the trajectory of their health and their performance.

Andres Preschel: Obviously you are exceptional at helping folks understand what they have in the tank, what they're capable of and taking that and unleashing it, right? But why is this something that is so natural to you? Why does it make so much sense to you? If you can take us back through maybe your early life history, your career as a professional, you know, why does this make sense to you?

Kristen Holmes: Yeah, well, I was an athlete myself. I played two sports in college. I played basketball and field hockey in the Big Ten. And then I went on and represented my country for seven years on the U.S. national team. So, you know, this project of trying to understand my body, trying to understand my psychological functioning and how that laddered up to me performing or not was always of you know, massive interest. And then I went on to become a coach. I coached in the, you know, NCAA. So I was a, as a collegiate head coach for 13 seasons. So really trying to help my athletes, you know, understand, you know, what it is that they needed to do to kind of flourish, you know, on the field, but also off the field. And I really, you know, my, my academic background is in, is in psychology like you and in psychology and physiology. So I was really trying to create a robust performance education that would help my student-athletes at the time understand the factors that influenced their ability to show up. We were collecting lots of data, so I was really one of the earliest adopters using heart rate-derived technology. I used heart rate variability. I think I was probably one of the very first NC2A coaches to use heart rate variability in an applied setting as a measure of readiness. Then, I used GPS, so I was using a lot of external load as well as subjective load, so the factors of human performance, objective, subjective, and internal. I was taking in a lot of those data. We had a robust framework around the core psychological needs, so we were tracking a lot of those data as well, those subjective data. And I was creating really a model to try to predict performance or capability tomorrow, capacity tomorrow. And what I realized really quickly is nothing that I could gather in the two hours that I was with my athletes and collecting a lot of these objective data and subjective data None of it could really predict how they show up tomorrow. You could say, oh, my model is flawed, but I think now I've come to realize, and really, one of the reasons why I left Princeton University, where I was teaching and coaching, is because I found this technology in Whoop, where it basically is giving you a picture of what's happening 24-7. So, what I learned in my environment at Princeton is that it's not just the two hours that they're with me or the three hours that they're with me, it's the other 21 hours that actually have more influence on how my athletes are gonna show up tomorrow. So, I became really interested in these other 21 hours of the day. And that's with the kind of food that we're putting in our body, the timing of the food that we're putting in our body, which we can talk about circadian things, but I'm really, my PhD work is all in kind of circadian behaviors. how we're sleeping, our social connections, our hydration levels, all of these things are going to impact our ability to recover and show up tomorrow. So it's not just about how we're training, it's these other things that are equally as important. And I think quantifying those things is really the opportunity and kind of where we're at today is that we have beautiful technologies that helps us understand how we're adapting and how we're, you know, and all these factors that we know are most predictive. That's right. Most predictive of, you know, optimal functioning. We can kind of track and quantify. We don't have to guess anymore.

Andres Preschel: It's not just that you can capture more hours when you're not with the athlete, but it's higher quality hours considering the confounding variables that you're eliminating, essentially. When you have an athlete with you in a performance setting, there are all kinds of stressors that are influencing the physiology. Obviously, you want to prepare the athlete to perform exceptionally under those circumstances and even more stressful circumstances. When you remove the confounding variables and you measure how they're recovering and how they're sleeping, I imagine that you really get a better grasp of their true potential. Can you actually take us through with the whoop, for example, why It's so much more important to look at the sleep scores rather than what's happening throughout the day or immediately before or after performance. Why are the sleep scores so valuable in predicting that performance day in and day out?

Kristen Holmes: Just so folks know, WHOOP is a 24-7 physiological monitoring device. There's no watch face. We're just collecting heart rate data 24-7. Then we have algorithms that basically synthesize that information and give you insight across sleep, recovery, and strain. strain, how you build cardiovascular load, recovery, basically how you're adapting to external stress, all sorts of types of stress that you face in your life, and then sleep, which is to your direct question, how you're sleeping. So how much quality sleep, how consistent is it, how sufficient is it, which are kind of the three pillars of sleep. But yeah, I mean, what we saw very clearly is that if you look at training in isolation, so volume and intensity over a course of a two-hour period, If you're in a maintenance phase and you're working with elite athletes, there's not really a whole lot I can do to them in two hours that's going to move around next day recovery, for the most part. What's going to move around recovery the most is how I sleep. When sleep is really good and I'm training the athlete appropriately, for the most part, they can repeat that. pretty consistently. You can repeat that volume and intensity if they're getting the requisite amount of sleep. It was very clear to me early on that sleep was the greatest natural performance enhancer that we have. To not consider it, and for athletes not to really double down and try to get as good at it as they can, was really a disadvantage. I think in my environment when I was coaching, we really saw sleep as a competitive advantage. We're in an environment, Princeton University, it's academically extraordinarily challenging, arguably one of the most challenging academic environments in the world. We were winning Ivy League championships year after year, we were vying for national championships, we're a nationally ranked team every single year. So, the demands on a student athlete at that level are pretty high. So, I think even in that environment, we figured out how to sleep. And that really, I think, was one of the bedrocks of our ability to win 12 Ivy League championships in 13 years. We had a lot of success. And a lot of that was a result of just my athletes being available. And I think when we think about sleep and the power of sleep, it improves your chances of reducing illness, reducing injury, and allowing you to show up as the best version of yourself. apply quality effort, you know, in all of your pursuits. And when you do that after, you know, over and over and over again, you get pretty good.

Andres Preschel: Right. So, you know, if we look at exercise and training as this stressor, as a hormetic stressor, we can only truly derive the value of that induced, self-induced stress if we can provide the right mechanisms of recovery, the right environment, the right nutrition time off. But if we can Not only I mean obviously sleeping more can support the recovery but sleep more efficiently and having a data-driven approach to sleep more efficiency is what makes a difference in driving the most from these hormetic stressors. So can maybe before we get into, there's a ton of stuff that I want to cover with you. We have a limited amount of time but can you take us through what are some of the key takeaways for an athlete to sleep more efficiently? And your particular area of research is in circadian biology and circadian rhythms. If let's say you have an athlete that's traveling across different time zones, sleeping in different environments, what are some of the ways that they can sleep more efficiently?

Kristen Holmes: Well, circadian rhythms are basically physical, mental, and behavioral changes that follow a 24-hour cycle. One of the most known circadian rhythms is our sleep-wake cycle. When you travel, your sleep-wake cycle is really disturbed. What happens is you end up having what's called circadian desynchronization. So that means what your body wants to do, so what is naturally happening endogenously, is at a sync with the cues that you're getting from the environment. So if I go from the East Coast to the West Coast, and now all of a sudden I'm three hours behind the East Coast, it's gonna be light out when my body thinks it's dark out, right? So I'm gonna start to feel sleepy when everyone else is awake and alert, or maybe I need to be awake and alert So, that conflict of the external cues and what's happening endogenously creates what's called this misalignment or desynchronization. And when you do that over and over again, that can cause some pretty negative health consequences, metabolically and cardiovascularly, which we can go into. But in the short term, you're going to have decrements in performance. So, you need to give athletes the requisite time to adjust to that new time zone. And really, the levers that you want to pull to adjust to your new time zone are, you want to view light on that new time zone schedule, you want to eat meals on that new time zone schedule, you want to go to bed on that new time zone schedule, you want to wake up on that new time zone schedule. That all can be really difficult, though, to do, especially falling asleep. You need to think caffeine can be a really good strategy, so you might have it at 3 p.m. on East Coast time, or you want to have it Yeah, you want to basically just advance the caffeine so you can delay your sleep onset. So, slow your sleep onset down. So, that means it might be it's midnight back on the East Coast, but it's 10 o'clock or 9 o'clock on the West Coast. And that's actually when you want to fall asleep. So, you use caffeine to make sure that you Don't fall asleep too early, essentially. Or, you just bite through that sleep pressure. But, invariably, you're going to have probably a crappy night's sleep. So, with athletes, you want to just give them the time to recover. But, I think back to just what drives sleep efficiency. is this consistent sleep-wake time. There's no question about it, and I've accessed a whole bunch of data in this area. I do a lot of research. When people have unstable sleep-wake time, that is, there's a lot of variability between when they go to bed and when they wake up, they will have less efficient sleep. Those folks end up having to spend more time in bed in order to get all the sleep that they need, in terms of sleep and REM, to wake up restored and refreshed. One way to spend less time in bed is 100% to stabilize when you go to bed and when you wake up. And that really does drive our sleep efficiency.

Andres Preschel: Right. I recently was putting together, just compiling some of the best and latest research on sleep to create a webinar with my team. And the way that you just described these sleep-wake cycles, I mean, I just absolutely love, I think anyone can appreciate this, but as a physiologist, I just love the way that you made it so practical and accessible for folks. to understand. And so if we go to this sort of like resistance or physiological resistance, right? Like as someone is traveling across time zones, you're in this new place and you are doing everything possible to sort of fight against what your body's used to so that you can perform your best in this new time zone. How long does that process take to return to your optimal performance or function? How quickly can you get to this new sort of natural balance?

Kristen Holmes: It's about one day for every hour, essentially.

Andres Preschel: For every hour difference. Okay. And do you move incrementally by hours to sort of shift into this new rhythm or do you just kind of do it? Is it like an all of a sudden cold turkey? Boom, I'm going from an 8am Eastern Time breakfast to a 12pm Eastern Time breakfast just right off the bat?

Kristen Holmes: Yeah, I mean ideally you start to shift before you travel just slightly. You know, a half an hour, half an hour, half an hour, half an hour. That could be an amazing strategy to basically acclimatize, kind of get your body slowly used to this new time zone, so wherever you're going. Another strategy is to opt out of the jet lag by not acclimatizing. We did this with a soccer team. We ended up winning the national championship. They were an East Coast team. They flew out to California. and we basically kept them on their East Coast time with all those levers that we talked about. It was just the timing of the games. They're 1 o'clock and 4 o'clock Pacific time, so we were able to navigate all of our meals, all of our light viewing, all of when they would naturally be working out anyway on East Coast and meal timing. and sleep-wake time. So we basically kept all of those four most important circadian cues, we kept them on East Coast. And we just applied those timeframes to the West Coast. And we actually were able to look at their physiology and saw no physiological perturbations. So they basically stayed, when you look at markers of recovery, like heart variability and resting heart rate, If you try to acclimatize for those first four days, first two days, if you're going from East Coast to West Coast, first two to three days, it's going to take you about three days to get back to your physiological baseline of where you were in your home time zone. So what we saw when we did this experiment is we didn't see any changes in their physiology because we kept their circadian rhythms aligned to their home time zone. they never shifted, and never forced to shift. It was really powerful. When I travel, that's totally what I do all the time. To the degree that I can, in terms of scheduling my meetings, I basically literally stay on East Coast time. I get there, I'll go to bed at 7 p.m. if I'm on the West Coast, because that's generally, I go to bed at 10 p.m. on the East Coast. And it works like literally like a charm. Like I have no physiological changes. I come back home and I'm boom, ready to go.

Andres Preschel: And how about, because I know sleeping in a new environment is generally stressful. How do you accommodate this new environment so that it's suited for optimal sleep?

Kristen Holmes: Yeah, that's a great question. There is some research that shows folks who travel, half their brain is essentially still awake. That's why we tend to have a lot of disturbances. If you're tracking with a tracker, you can see, wow, I had double the disturbances than I normally do in my home environment. What you could do when you get to your away environment is just cold, dark, quiet. Generally speaking, hotels have all these little lights everywhere. An eye mask, I think, is just absolutely crucial. I have those little hair clips, those claws. I bring those, so the curtains are like … totally pulled together, so there's no little light. I put a towel by the door to kind of block out the noise, because a lot of times, just the shutting of doors and everything. Earplugs, 100%. And then I try to make my room as cold as possible. I actually, there are hotels that are sleep-approved, that think about the hygiene in the way that we're talking about, and make sure that the room can actually get cold enough. The Sleep Foundation now recommends, I think, 66 to 68 is an optimal temperature, which is really cold. But that's really optimal sleeping temperature. So, yeah, I try to find hotels that I know that I've been to before, chains that I've been to before that I know really have all this dialed in. But yeah, those sleep hygiene aspects are really important.

Andres Preschel: Yeah, I personally set mine to 62 and I'm starting to think maybe it's a little too cold, but I do wake up in the night. I do wake up occasionally and I'm like, ah, man, it's a little sweaty. I mean, yeah, I mean, no, I mean, sometimes I get some, most of the time I'm really cold and it feels great, but there are times, I think it's when my girlfriend is there. She just has, she is like, I don't know, she just carries so much body heat somehow. I have no idea how or why, but I think maybe that's, that's the case.

Kristen Holmes: Well, to answer the question of what's going on with your partner or your girlfriend, there are different times of the month where actually women run hotter. And it's kind of in the two weeks for naturally cycling women, so women who are on hormonal birth control, who menstruate, generally speaking, the two weeks leading into menses Generally speaking, their temperature is going to be a little bit higher. So, they in fact will experience more sleep disturbances in that week leading into menses than the other times during the month. So, that could be why she's running hot.

Andres Preschel: It makes sense because I think she typically likes to spend time with me, whether it's conscious or not, while she's doing her menstrual cycle, the menstrual end of the cycle. I'm just joking there. That's funny. Yeah, that's probably it. That's probably it, right? She asked me to take her out to eat and buy her chocolate. I'm just kidding. But speaking about women's physiology, how do you consider that when, let's say you have a female athlete, when a female athlete's traveling, how do you consider all of these variables to be as effective as possible in maintaining and optimizing their performance?

Kristen Holmes: Yeah, I think female athletes is just kind of recognizing where you're at in the cycle. Again, if you're naturally cycling, there's going to be these very predictable hormonal fluctuations that happen that are going to create changes in body temperature, are going to create different nutritional needs, different electrolyte needs. So, I think just being aware of it, you can kind of stay ahead of it. And there's no reason why at any point in your cycle you can't perform to your potential. It's just a matter of kind of staying ahead of some of the symptoms that can creep up to make sure that you're maintaining balance. And it's really just around just knowing in the luteal phase, you probably don't want to fast, for example, because your body's already it's just a really metabolically expensive time. So, if you're cutting back or restricting calories, you already need a couple hundred more calories during that time frame. So, if you're cutting back or restricting calories, that could put more stress on your body, which can interfere with maybe menses or it can interfere with when you, you know, it can maybe delay your period or make your period come early. So, yeah. So, just understanding kind of the needs across the cycle, I think, is a really important source of insight for any female athlete, so they can just kind of stay ahead of it.

Andres Preschel: And what kind of difference do you think it makes for a woman athlete or not to be in tune with their cycle and their biometrics on a day-to-day basis? What difference will that have on their general health, well-being and quality of life?

Kristen Holmes: I mean, any human being, frankly, like I think should. The science is so good. The technology is so good that, you know, we can give you very reliable insight in terms of your skin temperature, your your heart rate, your heart rate variability, these markers that let you know how you're adapting to life's stress, how you're adapting to the food you're putting in your body, how you're adapting to the hydration levels, how you're adapting to training, what your sleep looks like, these things that we know our behaviors that we know are going to influence your ability to show up and be your best version, the data is there for us. I think for any person who's looking to be able to live their values with as much joy and energy as possible. Understanding the trajectory of your health, I think that's so empowering, and why wouldn't you want to know? So, I think these data are there for us, and it's just a matter of understanding how to understanding how our behaviors are kind of laddering up to these objective metrics, and then be able to make conscious choices about stuff that's contributing positively versus stuff that might be detracting from my energy and my happiness levels. And then at that point, I always say, performance is then kind of a choice. Which to me is like super exciting what my whole entire career has been studying like my thesis performance is a choice You know that was really like that we can choose our performance levels our attentional capacity our our motivation our effective effort like we can really Manipulate that with our behaviors, which I think is really exciting

Andres Preschel: And while women can measure their biometric data accurately, as far as the devices go, what is there to say about the lack of representation for menstruating women in the research and the overall efficacy of what this data means for them, right? Because if you look at the vast scope of the research that's done in postmenopausal women, so what is there to say for the young woman who's looking at her biometric scores?

Kristen Holmes: I love that you highlight this, because the research is scant. I literally just addressed Congress a couple weeks ago on this very topic, that we know that we're not where we need to be, and when you know better, you need to do better. We're definitely trying to change things, ensure that the NIH has some guardrails in place that basically kind of force researchers to include women in their studies. But yeah, I mean, women have been left out of research. And as a result, we don't know as much about female body. I mean, you know, women have basically been treated, and to quote Dr. Stacey Sims, like small men in terms of how we train and, you know, any and all the considerations that you would normally take or can kind of consider when you're thinking about optimizing training, we've basically taken what we know from men and applied those same principles to women. And as we're learning, that's just not the right approach, right? We have very different things happening hormonally across our four-week cycle, roughly, and we need to be considering that. I think at Whoop, we've really tried to take the bull by the horns and do a lot of research. We have huge amounts of data. We're actually about to launch our women's 2.0 study. We did our 1.0 study a year and a half ago, analyzed all those data, and it was really interesting. We found that there were very clear for HRV and heart rate changes during the follicular phase, which is kind of the low hormone phase, versus the luteal phase, which is the high hormone phase. There's a suppression in heart rate variability, an increase in heart rate during the luteal phase, and the opposite during the follicular phase, which is to suggest that, again, The luteal phase is more expensive time, your body is working harder to maintain homeostasis, so we have maybe slightly different training considerations or just modalities and we need to kind of shift our modalities a little bit so we can kind of compensate for some of these hormonal shifts. And then in menses and ovulation, during menses and ovulation, this is a time where women have always been told to kind of sit back and relax and take it easy. But actually, the opposite is true. This is when we're in our lower hormone phase. Your body is not working as hard to meet homeostasis. As a result, you have more bandwidth to put toward your training. So those are really opportunities where women, I think, can really push it and generally feel better, more energetic, so you can put more into your training. We published that research, which was really exciting. We've been doing a lot of research in this area to try to level the playing field. Obviously, we're not going to make up for the last 30 decades of no-exercise-phys research, but at least we're trying to make a bit of a dent.

Andres Preschel: Yeah, I've become passionate about this through my girlfriend because her specialty in the health and wellness realm is women's neuropsychophysiology and understanding the female biorhythm. So she's worked closely with Kayla Osterhoff, PhD in women's neuropsychophysiology. She coined the term female biorhythm and she's a huge fan of Stacey Sims as well. So I just want to say that as a man, I have benefited from knowing her physiology and understanding how she and how hormones and everything changes throughout the course of the month. And I think that it's genuinely made our relationship way stronger, more understanding, more empathetic. And I just want to say for the men that are tuning in, it's a superpower to understand women's neuropsychophysiology and the female biorealm. It's actually, in my opinion, the most exciting biohack ever. And it's a great way to start a conversation telling a woman like, I know what most men don't.

Kristen Holmes: Exactly. I tell my son that too. I'm like, this will put you in like 0.0001 of the population. Like this is such a competitive advantage. There's nothing sexier, right? Like than a guy who like understands like his partner's like body. Like, I mean, that's like amazing. Yeah. I totally agree. Absolute superpower. Guys should be leveraging that.

Andres Preschel: And so what can women expect, let's say, from the Woop platform in the next few months or years with regards to their unique physiology?

Kristen Holmes: Yeah, I mean, we're really going all in on insights for women. So you mentioned perimenopause and menopause. This is another area that's really not very well understood. I think women have always felt a lot of shame around some of these changes, losing your menstrual cycle. it can be really hard. It's just this new phase of your life. There's changes in your sleep, there's changes in your circadian rhythms change. There's just all these really profound shifts in your physiology, even in your brain, that can have a really traumatic effect on a woman. The fact is, we don't know a lot. We don't have a lot of research in this area. That said, our new study, our 2.0 study, is going to include a lot of questions. We've been gathering a lot of questions around perimenopause and menopause, just symptoms, how women are feeling. A lot of subjective insights that we can then kind of look at up against our objective metrics to try to put together this mind-body interaction so we can kind of tell a better story to help women maybe get through these tougher kind of phases of their life. So I think you can expect that we'll have a lot of menopause, perimenopause coaching on our platform. We'll have menstrual cycle coaching, I think is going to get up-leveled. We already have menstrual cycle coaching, but Imagine a 2.0 where we're able to track new things. Not just when you're getting your period, but fertility and ovulation potentially, and things of that nature. I think there's a lot of exciting stuff that's being researched right now that hopefully is going to get baked into the experience very soon.

Andres Preschel: Amazing. And if I can make a suggestion, I would love to see some way that men can maybe track their partners and get insights about where they are in their cycle and how they might be able to, I guess, support, understand, empathize with their partners. I think that would be quite valuable.

Kristen Holmes: I mean, I get so many direct messages from from guys who are like, Oh my God, you need to help my wife, you know, like, like, how can we help my wife, you know, and so I really do empathize with the guys out there who kind of see their partner going through, you know, maybe it's just a really painful period, you know, like literally painful menstrual cycle or, or, or, you know, kind of going through perimenopause and experiencing all of these changes and hormones. Yeah, so I think there's a lot we can do for both the partner and the woman who's going through it.

Andres Preschel: Wonderful. And if I may, I want to ask you a few questions about the way that we rely on data to make decisions and if and how that can lead to deep states of intuition and physiology. I know that you'll appreciate this word as much as I do, interoception. So that deep bodily awareness. So how can we use data to eventually achieve this deep bodily awareness? And is that the goal ultimately with something like Whoop or do you guys want to retain people on the data for as long as possible? Or is it a blender? You can share your thoughts.

Kristen Holmes: Yeah, I mean, I think it's a blend. I am so on the same page as you as just you're talking. I, you know, I, and this is how I thought about it when I was coaching, you know, like when we started introducing objective data, it totally improved the conversations I had with my athletes because I, we had like a, a common language. It wasn't about me being like, you're tired. Why aren't you showing up? I could see, okay, wow, sleep is really compromised. Or, you know what, they're just not responding and adapting to the training in a positive way. Oh, you know what, I just broke up with my boyfriend. Or, you know what, my grandma's really sick. All of a sudden, this subjective data opened up a more humane conversation. I think people fear that data is going to detract from these conversations, but I've just found at every turn, and I have thousands and thousands of repetitions interacting with folks, athletes, and CEOs, and military operators, and spouses of military operators. Just a gazillion of these conversations where data elevates the conversation in a really powerful way, and helps you understand where to apply your effort. I think that's the other piece, that there isn't a gazillion things that are going to really move around your mental, physical, and emotional capacity, for the most part. And a lot of those things that are gonna move it around manifest in the subjective data that we can then say, hey, listen, you're spending, yeah, nine hours in bed, but you've got 40 disturbances, what's going on? Oh yeah, I just, I'm so stressed. And all of a sudden you can put together a story and then most importantly help someone understand what strategies to deploy during the day so they can get the sleep that they need at night, for example. So, I think from my perspective, it opens up the door for a more humane conversation. And if you're not talking to someone, it just at least gives you a sense of what might be going on so you can then take the appropriate action to make it better. Now, I think the other piece is that when you understand, when you have these data, I think to your point, you are more connected to your heart rate and to your body. And I'm at a point where I don't even need a secondary pull or heart rate strap. I don't need anything on my wrist. I can feel the intensity of my run and I know what zone I'm in. Just from all these repetitions and being able to see my workouts retrospectively and see what heart rate zone I was in, I'm like, all right. It's eliminated the need, I guess, for a lot of extra technology because I can feel my body so much more strongly.

Andres Preschel: Right. And in a world that isn't going to call us in when we have high recovery scores, right, we're not in a perfect world, we would go to work and we would compete when we have high recovery and high, you know, good biometrics. But how do we optimize for the unexpected nature of performing? You know, it's like if I wake up on a low HRV day and I have to perform, What am I supposed to do then? And how does the knowledge of this low score, how is that going to influence my performance further? So what would you, what do you do with athletes who wake up, have to perform, but their scores just aren't there? Their biometrics, their body isn't there.

Kristen Holmes: On the Woop platform, you can hide your recovery on any day that you want. So I definitely recommend athletes who feel like they're really affected by a lower recovery on game day, just hide it. And I think folks, I think that's, Physiologically, it's not really how it works. These acute moments where you wake up and you've got a lower HRV does not mean you can't PR that day. It does not mean you can't play out of your mind. Of course you can. It's really the sum of all the behaviors leading into that moment. the average of those behaviors, that is really going to be the predictor of how you show up. So, you know, any one-off like low HRV, that is not going to impact your performance. Now, if you've got four days where you're chronically under-recovered because of emotional stress or just you're over-training, you're under-fueling, you're over-fueling, you're under-hydrating, like that is going to add up and impact you on game day. But if you're generally speaking, tending to all of those things on average, well, it's not going to influence like that one off game day.

Andres Preschel: Oh, wow. I can I can just feel the athletes in my audience tuning in right now, taking a breath of fresh air.

Kristen Holmes: Don't stress like honestly, like it's not it is just it's just every it's really every day. You know, that's the cross that I think athletes that anyone who's trying to do hard things and in high stress, high stakes environments, the cross that you bear is just doing the right thing every day, right? And just entrusting that, you know, when it's that moment where you actually have to perform, it's everything that you've done in the lead up, like it's going to be there for you on game day. So, yeah, I think athletes can just totally take a deep breath and just realize that, hey, I'm a sum of my behaviors and I can bring it whenever I need to.

Andres Preschel: So I know this is a nuanced topic and it goes back to this theme of, you know, uh, some of your behaviors, right? Like if you take the sum of behaviors and, and let's say training sessions that you did, you performed on high HRV days versus just training for the sake of training back to back to back or just, you know, whatever, you know, what is the difference there between training on high HRV days and just training because your coach said so, even if it's, you know, can you make more out of less training sessions with high HRV versus. you know, more frequent sessions on whatever HRV.

Kristen Holmes: Yep. Yeah. So we did a cool study called Project PR and that's exactly what we found is that the athletes who basically listen to whoop recovery performed ran faster when they did this like 5k run. So basically everyone in the study was doing this 5k run. Some folks were doing just a non kind of HRV recovery-driven program, and the other ones were doing an HRV recovery-driven program. So basically, to your point, volume and intensity was modulated based on recovery. And the individuals who modulated their training based on recovery outperformed the folks who didn't. Daniel Plews did some research on looking at this very question. Mark Bouchette, a lot of the HRV gurus have basically proven that HRV trading with when you're primed to adapt to that load definitely is going to elicit more gains. So yeah, there's definitely something there.

Andres Preschel: And I just wanted to share that. Anecdotally, I experimented with this. I was addicted to road cycling and I was very cocky when I was road cycling. I just, I just, my competitive nature came out on the bike for whatever reason. And I was using the Strava app to monitor my performance. And I started chasing the KOMs, you know, getting the fastest time for all these different routes. I started to go and cycle a lot less, so rather than the four or five days a week, I was going three days a week. I was leveling up on that bike every single week nonstop and getting KOMs. It was all because I was looking at the biometrics. This is just an anecdotal report, but I thought that it was especially helpful for my cocky and competitive nature back then. So, for anyone that wants to take it to the next level, perhaps you can reference this research and make the best decision about your training based on your HRV. That's fascinating. And what can we do in this moment, for example, to modify our HRV? Let's say you're in a meeting and you find that your stress response is kind of getting out of whack. What can you do in that moment, if anything, to monitor your HRV?

Kristen Holmes: Well, we know that slow paced breathing is going to increase your heart rate variability and decrease your heart rate. So definitely, you know, a shorter inhale followed by an extended, a longer, longer exhale will bring your heart rate down. So. doing a few cycles of that can definitely, you know, modulate your heart rate right there and make you feel less stressed. You can do a cyclic sigh, which is a double inhale followed by an extended exhale. That has been shown. Yeah, yeah, exactly. Yeah, and they used whooping nut study. That was, we were in the biometric.

Andres Preschel: No way, get out of here.

Kristen Holmes: Heck yeah, heck yeah. Yeah, we're actually spinning up our second study with those, with his lab. Yeah, he's a science advisor to Whoop, so we love Andrew Huberman. Yeah, he's amazing. He wasn't always famous, so I met him when he wasn't famous, but he's really phenomenal, obviously, and has just totally changed, I think, our world, the high-performance world, in such a positive way. Yeah, it's making it accessible. But yeah, so the physiological side, the cyclic side, which is a double inhale followed by an extended exhale, also has been shown to reduce anxiety and stress as he demonstrated in that beautiful paper published in Cell. you know, do that 10 times, that will totally bring you down and kind of get you back, back in balance. And I think what I think folks don't recognize is that the degree to which we go throughout the day, just chronically activated. So, you know, if we think about the parasympathetic nervous system, which is, so heart rate variability is a function of the heart, originates in the autonomic nervous system, which has two branches, the parasympathetic synthetic, they're both competing to send signals to the heart. When we're really stressed, sympathetic is going to dominate. Your higher heart rate, adrenaline, cortisol, epinephrine. You can imagine, if that's happening across the day, we accumulate negative stress. And that negative stress ends up rearing its head. We might be so sleepy we fall asleep, but invariably, those are the folks who are waking up at 2 a.m. It's unresolved stress during the day, or chronic stress throughout the day. So, you really want to try to interrupt moments of stress with like bouts of rest or you know moments of activation with moments of deactivation and breath is a great way to to do that and and so if you've if you're in a situation where you're chronically stressed you will see a lower baseline heart rate variability right if you're managing stress really proactively you'll see that you know your heart rate variability should should improve so that is one way to modify it i guess this is what i'm getting at

Andres Preschel: What are some of the low-hanging fruit that you tend to see with people that have this low-grade chronic stress? Why is it there and maybe what can they do to counter that and put their bodies in a better recovery and performance mode?

Kristen Holmes: understanding kind of the root of the stress or the anxiety. You know, anxiety is really kind of this chronic worry. So, if you've got chronic worry, the only way to kind of address it is to deal with it, right? You kind of have to get to the source. So, you know, sometimes that means you got to talk to a professional, right? And try to figure out, okay, why am I anxious? Like, what is this, you know, what is making me uh feel this kind of you know chronic worry and and how is that chronic worry manifesting in my behaviors you know is that how am i uh what are the behaviors that i'm adopting to try to um you know mitigate that anxiety and invariably a lot of folks will you know, take over-the-counter medications. They'll maybe, you know, binge eat or, you know, it can manifest in just, you know, lashing out at a partner or a child or, you know, like, you know, anxiety can be and, you know, can be really, really tough. And stress is kind of just like these more kind of acute moments where we're just kind of stressed. Like, oh, I've got this deadline and I'm just like stressed. And I'm like having to like mobilize resources to like do this thing. So stress and anxiety are fundamentally different, as you know, and need to be kind of, I think, treated differently. So I think getting to the root of whether it's chronic stress or anxiety is really important. And once you kind of get to the root of it, I think it's adopting behaviors that will increase your tolerance for stress. Stress isn't going to go away. It's just the nature of modernity. But if you think about it from the standpoint of, how do I put as little extra stress on my body as possible, right? And a lot of that is actually related to these circadian things. So when we are misaligned with the natural light-dark cycle in terms of our mealtime and exercise and when we're viewing light, when we're restricting light, when we're eating, when that's out of sync, we put a ton of stress on our body. So any other stress that we layer on top, we can't handle. So at a base level, you want to try to just allow your body to operate as efficiently and naturally as possible. And a lot of that comes down to making sure we see light within 20 minutes of waking up. It's really important to get our sleep wake times, again, really stable. And how, when we view light, is going to facilitate whether or not we can actually stabilize when we go to bed and when we wake up. So when I see light in the morning, it's going to influence actually when I feel sleepy at night. So that's really important for folks to understand. And then restricting light in the lead up to bed is really important, right? That's the only way to release melatonin, that sleepy hormone. And it needs darkness in order to be released. Melatonin isn't just about making us sleepy, it has neuroprotective effects. It has a wide-ranging impact on every cell, tissue, and organ in our body. When we don't release it, that is, we push past our natural pressure for sleep. we end up not releasing as much melatonin as we should, and that has short-term and long-term consequences. So again, stabilizing sleep-wake and making sure that we're viewing light appropriately will definitely decrease the amount of stress we put on our body, increase our tolerance for stress, which is going to allow us to adapt to all the demands in our life in a more functional way. The other behavior that puts huge amounts of stress on our body is eating after the sun goes down. which I don't think folks really realize, but there's lots of really good research on just metabolic outcomes in early eaters versus late eaters. You really want to try to eat a bulk of your calories early in the day, because that's when we're most primed to metabolize food and utilize nutrients. eat big meals close to bedtime, we're basically diverting resources that would typically go to recovery and rejuvenation to digestion. So that puts, again, a lot of stress, a lot of metabolic stress on the body. So late mealtimes, lots of light during the day. And when you wake up, restricting light at night. In the lead up to bed, so, so critical. Mitigating stress throughout the day with some breathing, really important. And then exercising. I think if we exercise really late at night, it can make it really hard to fall asleep. And if we're certainly for working out enough like planet fitness, and it's like super you know lit Again that can impact our ability to fall asleep and stay asleep So just like try to be conscientious of when we exercise that said the benefits of exercise are so profound that you know It's probably better to take a knock on sleep potentially and exercise. I don't know I go back and forth on that, but yeah

Andres Preschel: Well, so essentially what you're describing in a nutshell, like in the grand scheme, at least the way that I see it is you're using data to try and maintain a biologically consistent lifestyle in the modern day, because these are cues and these are behaviors that we would otherwise do naturally at consistent times throughout the day when they made sense. And so because we have the convenience of being detached nowadays, we often forget how important it is to understand and honor our evolutionary to preserve mechanisms, our physiology, the way that it's designed.

Kristen Holmes: We haven't adapted to blue light, for example, after the sun goes down. We haven't adapted to eating at all hours of the day. We just haven't. And the result is metabolic dysfunction, cardiovascular disease, infertility. These have real huge effects on humans. So yeah, we just need to fight audacity, honestly, and try to put some of these guardrails in place so we can preserve our health.

Andres Preschel: Yeah, I mean our technology evolves exponentially faster than our physiology, so we have to make the equal and opposite effort to protect ourselves and live the best life that we can. I know we only have a couple of minutes left here, but I wanted to share this with you. I have a prediction as to why an earlier meal can improve sleep beyond the circadian consideration. And it's because when we have more time between our dinner and the time we fall asleep, we can essentially guarantee a deeper state of ketosis approaching bedtime. And from what I understand with my background in exercise physiology, you get this shift in the respiratory quotient, a downward shift in the respiratory quotient. You are technically, you have lower breaths per minute. And as a result, literally you have greater parasympathetic activity. So that can boost your HRV and actually I tested this further I started to see earlier, you know mealtimes and I started to sleep way better to your point But what took it to the next level? Was exogenous ketones by a brand called ketone aid which I think most of the Tour de France teams take I don't know if you're familiar with it and But I started taking this stuff and I'm not kidding you, with just six hours of sleep, I got the same recovery as my typical seven and a half to nine hours. It was insane. Like the nights that I can't for whatever reason afford. Oh yeah. The nights that I can't afford many hours of sleep, I take this stuff and I feel great in the morning. So I don't know if you guys have looked at that at all, but I thought it was extremely interesting.

Kristen Holmes: That was a beautiful explanation of the mechanism. But yeah, there's no question about it. A late meal will increase your respiratory rate, to your point. We see elevation in respiratory rate. Respiratory rate is a relatively stable metric. It doesn't really move around that a lot, but even just subtle shifts in respiratory rate actually has a pretty profound impact. Late meals is like early meals, like ending your last calorie a few hours before bed is the best hack for modifying heart rate variability. Because to your point, you're able to then put all of your resources, like you're not, because digestion is a parasympathetic activity, right? So when we're asking our heart to, when we're asking our nervous system to help digest food, it can't do all the other regenerative and recovery processes that it would like to do. So, you're kind of competing for resources when you're trying to digest and also sleep at the same time.

Andres Preschel: Right, your nervous system is preoccupied. And I want to get your take on this too, which is the temperature consideration of a late meal. You know, you have all this blood pooling into your midsection and that keeps you from getting the decline in core body temperature that actually helps drive sleep, right? It's actually the decline in core body temperature that is one of the main drivers of sleep, if I'm not mistaken. And so do you think that the actual food itself is maintaining that higher core body temperature? Have you guys looked at that too?

Kristen Holmes: Or am I just totally making this up and making inferences based on my yeah well digestion Digestion elevates your your body temperature that yeah, so and we know for sleep You need a decrease in in body temperature right in order to kind of get into deeper stages of sleep So this is kind of what you're seeing too again when you're having to digest food you have an elevation and respiratory you have an elevation in body temperature both You know not optimal for getting into deeper stages of sleep so

Andres Preschel: Yeah. Well, Kristen, I know that we're pretty much out of time here. I have one last question for you. Uh, just briefly, if you could put a word sentence or statement on a billboard somewhere in the world, what would it say and where would you put it?

Kristen Holmes: Oh, I love this question. Uh, I, I'd probably say performance is a choice. which might like piss some people off, but that's probably what I would say. And I guess I would maybe want something that's like, you have to kind of click into that and like understand what it means. But I think that people have a lot more agency than they think. And I think just that mindset that, you know what, like there's a lot of things that I can choose on a day-to-day basis that are gonna enable me to perform at a level that I feel really good about. A lot of those things are stuff that are democratically available. It's just a matter of creating a life where you can create that synchronization, I suppose, and that alignment So yeah, performance is a choice.

Andres Preschel: Amazing. Well, it's been an absolute honor and a pleasure to have you on the Know Your Physio podcast. I think that you are, without a doubt, one of the best fit professionals for our show because you can really, you're so good at taking this science and making it actionable, accessible, and showing people that in fact, It is a choice to apply this and to level up with it and through it. And we can't thank you enough for joining us here today, Chris, and it's been such an honor and pleasure. So that's all for today's show. Thank you so much for tuning in today. For all of the show notes, including clickable links to anything and everything that we discussed today, everything from discount codes to videos, to research articles, books, tips, tricks, techniques, and of course, to learn more about the guest on today's episode, all you have to do is head to my website on dresspreschel.com. That's A-N-D-R-E-S-P-R-E-S-C-H-E-L.com. and go to podcasts. You can also leave your feedback, questions, and suggestions for future episodes, future guests, so on and so forth. Thanks again for tuning in and I'll see you on the next one. Have a lovely rest of your day.