WHOOP Podcast - Women and the Research Gap: How gender disparities in research are impacting women's health

Episode Date: August 24, 2022

Emily Capodilupo, WHOOP SVP of Data Science & Research, and Kristen Holmes, WHOOP VP of Performance, join the podcast to discuss the perils of disregarding sex as a meaningful biological variable in research, which has implications in training, fueling, medication dosing, and so much more.  Emily and Kristen discuss why there are disparities in research (3:48), how exclusion has been both systemic and practical (7:53), the role lack of research has in diagnostics and in medication dosage (13:24), how wearables are well poised to bridge the research gap (19:01), pivotal research on how exercise is beneficial to pregnant people (25:11), the impact of training and pre-sleep feeding on women (29:02), and training modulations during different phases of the menstrual cycle (32:59).Other resources to check out:Stacy Sims on Nutrition Differences between Men & WomenWhy We Need a Title IX for ResearchPregnancy Study Shows Benefits of ExerciseSupport the showFollow WHOOP: www.whoop.com Trial WHOOP for Free Instagram TikTok YouTube X Facebook LinkedIn Follow Will Ahmed: Instagram X LinkedIn Follow Kristen Holmes: Instagram LinkedIn Follow Emily Capodilupo: LinkedIn

Hello, folks. Welcome back to the WOOP podcast, where we sit down with top athletes, researchers, scientists, and more to learn what the best in the world are doing to perform at their peak and what you can do to unlock your own best performance. I'm your host, Will Ahmed, founder and CEO of Woop. We're on a mission to unlock human performance. We've got a great episode this week talking about a very important topic, despite. and research focused on women versus men, but first, if you're an existing WOOP member, we have a special offer for you. From August 29th to September 4th, we're launching strain week, which means whatever your highest day strain of the week is during Strain Week will unlock

savings to match. So if you hit a 14-day strain, then you're going to get 14% off your Woop membership. If you hit a 20-day strain, then you're going to get 20% off a WOOP membership. Okay, you get the point. You can join this challenge by going to the Woop Strain Week team in your app before August 29th, so before Monday, and use the code ComStrain. That's C-O-M-S-T-R-A-I-N, ComStrain. To this week's episode, we are talking about the disparity and research. focused on women.

It's particularly appropriate giving women's equality day on August 26th. Two leading women at Woop, Emily Capitilupo, our SVP of data science and research, and Kristen Holmes, our VP of Performance, are joining us to break down

this important topic. Okay, they talk about why there is such a significant gap in athletic performance research focused on women, how that underrepresentation shows up in other areas, including medication dosing and prescribing, what recent WOOP research found on menstrual cycles and training volume, critical research Woop conducted with Dr. Sean Rowan of

West Virginia University on pregnant women that suggests exercise is beneficial to mothers and the babies they are carrying, and how wearables can help close the gap in research between men and women. A reminder, if you're a new member signing up for Woop, we've got the offer for you. Use the code will, W-I-L, and you'll get a $60 credit on WOOP accessories when you sign up for a new WOOP membership that can be used for battery packs, bands, WOOP body apparel, and more. That's at join.wup.com. Without further ado, here are Emily Capital Lupo and Kristen Holmes. Hi, everyone. I'm on today with our Senior Vice President of Data Science and Research, Emily Capital Lupo.

Hey Kristen. Hi, Emily. We are here today to talk about Emily's recent TED Talk, which expertly highlights the perils of continuing to disregard sex as a meaningful biological variable in research. The fact that female-specific data is rarely considered in study conclusions, despite the fact it has implications for women's health is really troubling. I love that this conversation is tied to Women's Equality Day, which commemorates the passage of the 19th Amendment to the U.S. Constitution. granting women the right to vote. Congress designated August 26 as Women's Equality Day in 1971. And I think that's the perfect stage for us to talk about a concept that's near, to both My Heart and Emmys, which is equality and research. Emily, would love to hear kind of what that means to you. And tell us a little bit about your TED Talk and just that experience in general. So, yeah, I gave my TED Talk back in May in honor of the 50th anniversary of the passing of Title IX,

which was originally in June 1972, so the 50th anniversary was this past June 2022. And it's really interesting to be talking about this topic on women's equality day because in some ways there's a parallel to the 50th anniversary of the passing of Title IX and in some ways they're still totally unrelated

events and unrelated and kind of scary and problematic ways. So, you know, when we think about women having the right to vote, everybody knew what happened on August 26, 1971. Like, every woman was aware that they didn't have the right to vote and then all of a sudden they did and that this really important thing happened. But when we're talking about gender equality and research, I think one of the things that's so scary is where as disenfranchised, right, as we were, you know, with not having

the right to vote, but most of us don't even realize it. You know, it's such a sneaky hidden problem, and we get told with equal confidence and with like equal heirs of scientific authority that this research applies to you. But when you look beneath the hood, which so few people do, you find out that like 6% of athletic performance research focuses on women. And the stats aren't really any better with really scary high-stakes stuff like cardiac surgical techniques and drug dosing and diagnostic guidelines for different conditions which affect the treatments that you get and all these different things. And so when we are underrepresented in

research and we don't know and in so many cases our doctors don't even know that we're underrepresented in the research that frames the best practices that they're now applying to us, we end up with really problematically worse outcomes. And, And that was really where my TED talk came in. I was talking about how specifically in the area of exercise physiology, females are extremely problematically underrepresented. Like I said, 6%. And that 6% stat is less than a year old.

So this isn't some weird number I dug up from, you know, before we were progressive and woke like we are today. The study came out 11 months ago. And it actually showed that over the six years that it studied from, 2014 to 2020, the trend was flat. And so we're not getting any better here. You know, the rate at which we're representing women is pathetic. And as a result, you know, we see some big consequences. We see that women get injured more. We see that women drop out of sports at twice the rate of men at puberty. And that by age 17, 51% of girls have left sport. We don't see

anything close to that in boys. And it's not because, like, girls are too girly for that and you know boys are more naturally athletic it's because once you go through puberty and your body changes these exercise training protocols and equipment and different things that are designed with male bodies in mind they stops fitting it stops feeling comfortable you start to get hurt and you drop out and all of these things are completely avoidable and i'm really excited to be talking about it today in honor of women's equality day but you know i don't call out that this is an area that not only are we not doing well in, we're not making enough progress in. And a huge part of that is, you know, very much unlike when women didn't have

the right to vote, like most people who are impacted by this, even in really scary ways, have no idea how much like they're being underserved and diserved. Yeah. I mean, what are some examples of just the health and equities that get perpetuated by, you know, excluding women in clinical trials, for example. Yeah, and let me back you up before I answer the question because, like, researchers, they don't even realize what they're doing, right? And I think that they would take issue with use of excluding. There's a couple of reasons.

One, in order to control for the confounding effects of the female menstrual cycle, it's more expensive. You're going to need larger studies for them to be properly powered. If you're going to look at gender, that's another variable. So you need a larger study for that. And so it makes doing the research longer, more expensive, more time consuming, right? On top of that, you know, we women also have some responsibility here. Women are less likely to volunteer for research.

And this is particularly true for any research that's, you know, invasive, you know, potentially painful. So things involving blood draws, you know, we shy away from anything that's, you know, potentially going to put us at risk for a scar with a lot of exercise physiology research involves muscle. biopsies. Women say no thank you to that. And so it is a little bit more complicated. You know, it's harder to recruit female subjects because we don't like the consequences of being research subjects. And so as a result, it's more expensive on the recruiting. It's more expensive on the actual executing. And, you know, probably more problematically, it's totally acceptable to do this. You know, you can get the most prestigious research grants out there and not be held accountable

for any kind of equality. So there's systemic issues, practical. issues, you name it, issues at every single level. But that doesn't mean that the consequences justify shrugging our shoulders and saying, like, it's too hard. You know, if you want to talk about some of the really scary places where things like this are manifesting, you know, it's also not even just research involving actual humans. Like, when we think of, and you know, if everybody takes a moment and closes your eyes and, like, picture a human, studies show that, like, 100% of men just pictured a man and something like 80% of women just pictured a man. Industry does the same thing. So crash test dummies used in testing car safety are the size

and weight of an average man. And so it's not all that surprising that women are 47% more likely to get injured in a car crash because, you know, the height and the placement of airbags, the size of your seat, all of these things are designed to be comfortable for men. Like I have no idea if my fancy car with its five-star safety rating, how it would perform on somebody my size, because I can pretty much guarantee you that their test dummy was quite a bit larger and heavier than I am. And there, there's really no excuse, right? It's not like men are volunteering to be crash test dummies. They're literal dolls, but they're using men. And then, you know, in all kinds of other places, this stuff shows up as well. We learn in medical

school, or medical students are taught that heart attacks present in a certain way. And you get taught, you know, people will say that they have chest pain. They will, you know, present with, you know, various different symptoms. And you are taught to recognize them very quickly because there's a cascade of different steps you want to take if somebody has having a heart attack. Well, women are much more likely than men to have what they call an atypical presentation of a heart attack. So they're more likely to show up with nausea and to be vomiting. They're also more likely to have shoulder or jaw pain. And doctors are taught that this is an atypical presentation of a heart attack.

And statistically, it takes them longer to diagnose those, which means that women who come in with these quote-unquote atypical presentations don't get treatment as quickly and therefore have worse outcomes. Now, this is an area where, like, there's a sort of systemic issue in how we're getting taught, right? So people define, quote-unquote, normal heart attack symptoms. as being male symptoms. And then we let everybody off the hook with being vigilant about identifying female heart attacks because we call it atypical, which without meaning to sort of gives people permission

to be less good at that or slower at that because it doesn't fit the quote unquote text definition of what a heart attack is supposed to look like. And so then it's like we excuse the slower diagnoses, but men and women don't get heart attacks in like wildly different rates. And it wouldn't be that hard. You know, I just explained it all to you in 45 seconds, right, to teach medical students that this is a typical female presentation. You know, I could fill a whole hour-long podcast, just example after example, right?

Male autism is normal autism. Female autism looks very, very different than that. And female autism is, quote, unquote, a typical autism. It takes them much longer to get diagnosed. And men outnumber women in autism. in research 15 to 1, but they're only four times more likely to be diagnosed. And there's a huge reason to think that females are underdiagnosed because they present atypically. And women suffer because it takes them longer to get diagnosed. They get misdiagnosed. I mean, another example is

ADHD. Yeah. Boys symptoms kind of manifest externally, you know, way faster and as a result, easier to diagnose. But again, I think as a result, young girls are kind of left to, struggle in school, for example, or something just atypical or abnormal as opposed to, you know, getting on a faster track to an actual diagnosis. You mentioned too just Ambien. I wanted to get your take on that. We were talking about it off camera. Yeah. Well, this is like a particularly, I think, pathetic example of the system really failing women. There were no women included in the clinical trials for the drug Ambien, which is a sedative commonly prescribed for insomnia and trouble sleeping. But men and women metabolize Ambien very differently. And so when Ambien came out based on the

results of the clinical trials, the dosing guidelines that were put out were only developed using male subjects. And so it was based on, it only was able to account for because it only ever looked at the way that men metabolize Ambien. But women metabolize it so differently such that receiving a male dose is a massive overdose. And in a clinical trial, people who receive experimental drugs are very, very closely monitored. And so if you were getting an overdose or having any kind of weird reaction, that would get caught really easily, corrected really quickly, and totally fixed before the drug ever made it to market. But once the drug is approved, it's actually not monitored very closely at all. And so women were getting

massively overdosed on Ambien for a very, very long time. An Ambien overdose is a really scary state because it can, not always, but it can cause you to have these wild dreams that you then act out, sort of like a very weird version of sleepwalking. But now imagine like, you know, you're cooking a gourmet meal, you're driving to the store, you're having like conversations with other people like all well completely, you know, sedated and unconscious and people were crashing cars, trashing their homes and then thinking that they got robbed, all kinds of wild things. And it took a long time to put these stories

together and tie them back to Ambien because it seemed like, you know, this sort of spat of unrelated crimes and strange events. And it tie you back to Ambien and to realize that they were being overdosed. And had they been included in the clinical trial, this would not have happened on anything close to the scale. You know, it really highlights why it's lazy and unacceptable and frankly should be illegal to put drugs on the market and say that, you know, these work on all people, hand wavy, hand wavy, women are just small men, they're going to work the same. I guess at worst, we should have said, you know, let's just approve this for use in men because that's who we've studied it on. And at best, we would have mandated that there were female

subjects. And, you know, by the way, like, you know, we're talking a lot about gender, but this shows up in a lot of other dimensions of human difference as well that get underrepresented. So we know that there are certain people of African descent respond differently to certain cardiac medications than Caucasian people do. And so for a while, we just sort of thought like, oh, you know, people of African descent are less healthy or, you know, they have less good hearts and it's genetic and whatever. And we were giving them the quote unquote, you know, like Caucasian drugs and they weren't working as well. But then we started to find that there were some other drugs that aren't typically given as like first line drugs in Caucasian people that work way better

in people of African descent. And when we started making the standard of care that they get different drugs first, they started having better outcomes. And so it's really important to think about, you know, what are the different ways that make people different? You know, pregnancy is another big condition here where, you know, all of a sudden the drugs that are totally safe for you to take just three months ago, all of a sudden, I'm not safe for you to take now. And, you know, we don't do enough testing on children. And there's, you know, reasons for that, you know, why we want to make sure that we're protecting them. Obviously, when people are underage, there's issues with consent and you do need to navigate that carefully. But, you know, you know, you know,

know, when we just sort of say, like, children are small men, women are small men, you know, postmenopausal women, and then we just shrug our shoulders when they have worse outcomes and we go, oh, well, they're old or like, oh, well, they're less healthy of a population, all these things. And it becomes really easy without, you know, any evidence on either side to shrug your shoulders and go like, yeah, that's too bad. But, you know, it's really important that people are aware of this, kind of going back to my opening point, that they know that they're being underrepresented, that they know that they're being given, you know, drugs or treatment protocols that weren't developed on people that look like them or are genetically similar to them or anything

like that. And that, you know, they get angry about that and they demand things because we know that this is more expensive. And so, like, to do inclusive, comprehensive research. And so the only way that we can actually get any kind of change, you know, we can write to our representatives and demand. This is something that the system is perpetuating because, unfortunately, nobody's complaining, and not because this is harmless, but because it's hidden. You know, obviously, we're super passionate about just the ability to do research in a kind of a passive, non-invasive way. And I think that's where wearables has been just incredibly groundbreaking on a lot of levels. You know, we can accurately monitor vital signs, you know, which tell us a ton about. In this case, you know, we're looking at females and we're looking at female physiology.

You know, how have you seen wearables really bridge this gap and provide more opportunities to conduct really rigorous scientific inquiries? Yeah, this is such a fun question because sort of, you know, why I work at WOOP in a lot of ways. Prior to Woop, I was working in the Division of Sleep Medicine at Brigham Women's Hospital, which is one of the Harvard hospitals here in Boston. And then, like, enter Woop, right? And we've taken all of that technology. and we've boiled it down to something that, you know, for no incremental cost per night, you can get something similar. And granted, it is not the same thing as an in-lab polysumography,

but it approximates a lot of the different same metrics that you can get from a polysumography test from your wrist. So no wires. And so we have these data sets where we have hundreds of thousands of people for years, you know, years and years. And so we can look at things like how sleep is evolving when people change behaviors, how sleep is affected across wide different cuts of different demographics and different things like that on a scale that just was completely, and still is today, completely unimaginable in traditional academic research. And we've actually been super lucky because we've gone back and partnered with that lab that I left to come to whoop. And we've said, look at this data we have. Let's explore some questions in sleep that you've always wanted to ask.

But, you know, it would cost a billion dollars, you know, billions and billions of dollars to get a data set like the one that we have, but collected through like traditional academic sleep medicine routes. And, you know, forget that. Those grants do not exist. They're not going to exist, right? We've worked with them, you know, with some of the most brilliant leading minds. and sleep on whoop data to answer really important questions. We published a paper with them a little over a year ago looking at the relationship between sleep and mental health.

And while those patterns are very, very real and important, they're too noisy to show up in a sample of 20 people. So like in those kind of typical 20 person in lab sleep studies, you never would be able to answer questions like this. And so it's creating opportunities for research equality that, you know, for all the reasons we were talking about earlier, like women are less likely to participate in research. Well, they're not a lot less likely to wear a whoop. You know, we talk about like women are less likely to come and do a research study because they're the ones responsible for child care. And so, you know, they're staying home to babysit maybe while their husbands are doing a research study or something like that.

Well, you know, whoop you wear wherever you are. So I can be wearing a whoop while, you know, sleeping next to my baby next door or, you know, while providing child care and all of those different things. And so we've made it possible to have the scale of the data that lets us slice and dice data across all these different demographic lines and find patterns that just, you know, academic research, you know, even, it's not that they're too stupid or whatever to ask these questions. It's questions they've wanted to ask. but the system isn't set up for and our system is. And so it's been really, really rewarding to partner with academia in order to get their hyper-specialized knowledge and brains and everything and then are really,

yeah, all that expertise that they bring that subject matter, expertise to pair that with our totally unprecedented data set, both in terms of the breadth across different types of people, but as well as longitudinally being able to follow people, It's really hard to get someone to do something every single day for, you know, three years. But our members are doing that all the time for us. And so we can go back and look at, you know, how is your sleep in 2019 comparing to now and ask really interesting questions about things like that.

And being able to do that is really exciting. And I think wearables we're just going to see are unlocking more and more freely important research because of that. You know, it was super evident in our study with West Virginia University and Dr. Sean Rowan, where we're able to, you know, again, look at this unprecedented population over long period of time, really looking at the autonomic response of women pre, during, and post-pregnancy. Maybe talk a little bit about just why this gap in research for pregnant women is actually is so big. And where do you kind of see the opportunities there with our technology to really, you know, increase the pace and power of this type of research?

Yeah. So the U.S. Code of Federal Regulations defines pregnant women and the fetuses that they carry as a vulnerable population requiring additional protection. But what it basically means is that there are issues with consent and can an unborn baby sort of give consent and it makes sense that we have specific concerns around that. But as a result of protecting pregnant women from being research subjects, we created this kind of funky double-edged short almost where we've locked herself into forced acceptance of not knowing, right? Like, if we're protecting them from being research subjects, okay, we can't do the research. Well, if we don't have research, you know, we're still going to have pregnant women. So how do we treat them? How do we know what to do? You know,

we're left with like a whole bunch of bad choices, right? It's like animal models. You know, are we really chimps? Are we really rabbits? Like, to what extent? I don't know because I can't do the research in humans to find out. So we use animal models. We're left with research in not pregnant women. And again, like those of you who have been pregnant will likely know that pregnant you and not pregnant you are in a lot of ways wildly different. You know, importantly, you have, you know, super important changes in hormones that can affect all kinds of things. There's a lot of important questions. And so we tend to like err on the side of caution and just try and be really safe, but it's hard to know what's actually safe without doing the research.

And so we end up with these funky guidelines. Like we tell pregnant women not to exercise. And, you know, there was this big fear that, like, excessive exercising can cause miscarriage, especially in the first trimester. People who exercise during pregnancy, it turns out actually have way better outcomes. They tend to have lower rates of gestational diabetes. they tend to have less back pain, you know, they sleep better, they have better moods. So we thought for decades and decades and decades that we were erring on the side of caution and protecting women by telling them not to exercise when in fact we were actually giving them some of the most harmful advice we possibly could because we were denying them one of the most

harmless and helpful things you could possibly be doing for your pregnancy. And, you know, interestingly, babies born to people who exercise throughout pregnancy also tend to have, you know, signs of improved cardiovascular health. So you really are exercising for two in a kind of cool way. Like your baby's a little bit more fit when they're born. And so, you know, we pat ourselves on the back for, quote unquote, airing on the side of caution. But, you know, we really messed up there. And what's horrifying to me is that guidelines have been really slow to adapt. And a lot of women still get that advice. And,

you know, some of it is just inherited folklore. You know, their mothers are telling them what they're obese had previously told them. And, you, people pass these things down on the mommy blogs and all these kinds of things. And then we perpetuate it with, you know, this hyper-gent whole prenatal yoga where your heart rate doesn't go above 80. And, you know, we need our doctors to be enough up to speed on the research that they're fighting against that because there's so much out there that's still perpetuating what we now know is wrong. Yeah. You know, if we look at workload and capacity during pregnancy, I mean, that's like one time point on the continuum. And if we zoom out, we've got this entire reproductive health continuum that we have an opportunity to explore.

You know, I mean, we're looking at menopause. We're looking at medically assisted reproductive therapy. We're looking at collegiate student athletes and, you know, recovery and workload and the impact of pre-sleep feeding. I mean, we're looking at all of these, like, really cool questions to your point that literally, I mean, every manuscript that I'm working on, it's like, these data have never been reported. Like, it's like literally, we are, yeah, we just put our track shoes on. And we haven't even taken our first step yet. But I think the fact that we have this incredible opportunity, and I feel, I feel like you and I believe that we have this responsibility to really, I think, contribute to the science, given the fact that we have

these incredibly rich data sets that we can tap and so exciting. Yeah, and it's particularly exciting doing that, you know, as a female in this space. You know, Kristen, you and I run the two research teams at Whoop and I think both because the technology enables it, but also because, you know, Austin, like, all. our daughter to the ones leaving out if this research doesn't get done. It's absolutely like a sense of responsibility. And I'm really grateful that, you know, the rest of the company's leadership teams are supportive of us, you know, taking on this crusade and, you know, evangelizing, using our technology to close the research gender gap. I think about my daughter, you know, and she's,

she's an athlete, she plays basketball, and she plays basketball, and she's super active. And And she asked me all the time, you know, what kind of advice to give her? And it's funny, like, we just got finished analyzing a lot of the data from Shape, which is a study we ran in collaboration with Florida State University sports medicine. One of the things that we found and not surprising, and again, just to look at these gender differences, one of the questions we're investigating was what is the impact of feeding and how does that prior to sleep and how does that impact the recovery metrics that we track and how does that impact sleep? You know, we're kind of trending toward significance, but looks like pre-sleep feeding does not help recovery and does not

help sleep. So eating within a few hours of bed does not actually improve recovery markers of recovery and does not actually improve sleep. But if we look at the male research, the opposite seems to be true. I think, again, it's, you know, when we look at all of the research that's been done, there's none of this pre-sleep feeding, right, as it relates to kind of how it impacts the physiological markers that I think are important when we're trying to understand recovery and we're trying to understand, you know, what is going to contribute positively versus negatively and, you know, how does it actually impact sleep? A lot of open questions, I think, related to that. But I think, again, it comes down to the fact that, you know, women are not small men. Like how we respond and react

is going to probably be inherently different due to all these other factors that we outlined, you know, just our cycle and hormones and we're just physiologically different than men. Yeah, you know, it's We could do an entire podcast on gender differences in fueling. Like, you know, one of the things that we know is, you know, during different phases of your menstrual cycle, as your hormones are fluctuate, we actually, for those of us, with a natural menstrual cycles, so not on, you know, hormonal birth control or anything like that. We metabolize carbs versus fats differently at different parts of that cycle, so different times during the month. And you see all these kinds of like weird frustrating things where, you know, a husband and wife both decide to lose weight and they're going to do the keto diet, right? The guy all of a sudden starts sloughing pounds like crazy, right? Like losing weight and the woman's getting fatter. And, you know, she's probably being even more strict about it because it's not working and, you know, just wondering what's wrong with her. You know, there's huge hormonal differences in how we handle that feeling of starvation, right? Men lean up because they, think that, like, okay, I'm going to need to go and hunt, so I want to be as light as possible. And women start to store fat and, like, resist losing weight because their body's like, all right,

you know, times are tough. So let's like hold on to what we have. And so we lower our metabolism. We go into this kind of like preservation mode. And so the exact same behavior works wildly different on men and women. And I think even more frustratingly for women, like differently well at different times of the month. And then they just think that, you know, there's something wrong with them. They start to resent their partners for having so much success, right?

And you end up in this wild thing. And it's like, yeah, go read the research that swears that the keto diet is the best thing ever. It's men. Most of them is done in obese men preparing for bariatric surgery, which is its own issue. But it's mostly done in men. And then we go like, hey, people, miracle diet. And then we just go like, well, you don't want it badly enough or you must be cheated. or, you know, whatever.

And we make, you know, all the women, for whom this did not work, feel really bad about themselves. And, you know, nobody's looking at these things. And it's so important that we do because there's so few ways in which women are small men. And we have to get away from that, you know, lazy and outdated way of thinking. When we consider fueling, I mean, the same holds true for training, for hydration. You know, what we're going to be able to do, you know, how we're going to respond and adapt to training at these different phases of our cycle is kind of the same of how we respond and adapt to different foods at different times of the cycle. Maybe just talk a little bit about the findings from the study that you conducted with Laura fluctuations in heart rate variability and rest in heart rate across the fluctual and ludal phase.

Yeah, so we've talked about this in other podcasts, so we'll definitely link to those in the show notes. But we did a study in collaboration with Dr. Stacey Sims, and we looked at data from 5,000 women on whoop across 14,000 menstrual cycles. You looked at the cardiovascular nervous system's response to training by menstrual cycle phase. So if you're not familiar with menstrual cycle phases, you can basically think of, you know, we think about having our period and then sort of the rest of your month, you're not on your period. And a lot of people keep it that simple. But when you start bleeding, that starts your follicular phase, and that runs for about 14 days, although it does vary quite a bit. And then you ovulate, so that it means releasing an egg for those people who are trying to conceive. That's when you get pregnant.

And at that moment, you transition from the follicular phase into something called the ludial phase, which is, again, about 14 days, sometimes a little bit longer, and runs up until you get your period again in the follicular phase starts. So two phases, follicular and luteal. So in the luteal phase, our hormone levels are relatively high. And this puts us in a state where we tend to need more sleep because we don't sleep as well. And our bodies are less able to recover from exercise. So we see that for the same workout. On whoop recovery scores are lower, heart rate variability is lower. Resting heart rates are higher versus when we do similar to the same exercises during

with follicular phase. We recover from them faster. So you see higher recovery scores, higher heart rate variability, lower resting heart rate. And we get into sort of the why behind all of this, which we don't have time to do today. So again, check out the other podcast that will link in the show notes. But most people with a period who are experiencing these cycles have no idea that these differences exist. They might kind of be aware of like things. things like PMSing and getting crampy before they get their period and therefore be aware of not feeling as recovered. But even for people who don't sort of consciously have symptoms, these patterns persist.

And what we were able to demonstrate in our paper, which was published in the British Medical Journal coming up on two years ago now, was that if you modulate your training with this information in mind, you can actually train less and get the same outcomes or, you know, train the same amount and get better outcomes if you modulate it with your menstrual cycles. You want to do the hardest training, like the most strength-based training during your follicular phase. And then you want to do more base building, recovery focused, lighter stuff in the ludial phase. And it's pretty common to have four week, you know, training like phases or training cycles. But if you're on a part of a team, it might be totally random, whether the peak of those four weeks are hitting

your ludial things or they're hitting your follicular phase. And so the exact same training protocol applied to you, you know, with the right offset to your menstrual cycle or the wrong offset to your menstrual cycle, could result in you thinking that you're way worse athlete than you actually are and getting way less gains for all the same heart. work. And so, you know, what we really wanted to advocate with that research, which we have since turned into a feature in our product, is that if you train according to your mental cycle, the same amount of work will give you more gains. And what we showed with Project PR that we did in early 2020 is that if you train hard when your body's ready to train hard, you actually don't

get injured as much. And so it's not just about like, oh, you know, I'm 31. Do I really care if I like shave three seconds off my mile time. But I really do care if I injure myself and can't run anymore. So, you know, training smart that I can keep training longer and stay healthy is really important. And I know, of course, for people who aren't me and do want to shave time off of their mile, that is the most effective way to do it. Again, because academic research had failed to close this gap, we saw it as our responsibility to do that. And we were really excited to be able to do that research to partner with one of the leading, you know, female endurance researchers that there is in the world, Dr. Stacey Sims, to put that research in a top journal

and then to turn it into a feature in our product so that everybody, you know, who doesn't necessarily understand the science and doesn't want to read, you know, medical journal can just leverage this and see, you know, given what phase I am in my menstrual cycle and given how recovered I am, how much training should I take on today. You know, now they can do that with whoop are the only wearable that's offering anything even remotely close to that for half the population for the bulk of their adult life can now leverage this and train smarter than they could before. So I think at a high level, our capacity and our adaptation changes, our fueling needs, just our metabolism changes across these four weeks, our sodium

needs change. I know we've talked about this before just in our ludial phase, like how much We're going to sweat more. Our core body temperature is higher. And as a result, we're going to be able to adapt less efficiently to heat. So electrolytes and sodium can be an incredible intervention to kind of help offset some of those symptoms during the old phase. So there's, for me, a lot of the struggles are totally avoidable. And I think that's what's exciting here. And I think that's what we're kind of bringing to coaches and trainers. You know, anyone who's involved with a female athlete who's naturally cycling, you know, being aware of this allows, I think, the individual to train in kind of harmony or in concert with their cycle and understand, you know, the opportunities and limitations across these 28 days, roughly. Thank you to Emily and Kristen for coming on The Wooke Podcast as always. If you enjoyed this episode of The Wood Podcast, please leave a rating or review. subscribe to the WOOP podcast.

You can check us out on social at WOOP at Will Ahmed. If you have a question you want to see answered on the podcast, email us, podcast at WOOP.com. Call us 508-443-4952. New members can use the code Will and get a $60 credit on WOOP accessories. Okay, that's it, folks. We'll be back next week. Stay healthy and stay in the green. Thank you.