Women’s Training & The Menstrual Cycle: What the Science Actually Says | Lauren Colenso-Semple, PhD

Dr. Gabrielle Lyon: 00:00

Today, we're cutting through the confusion about women's hormones, fitness and muscle growth. Dr Lauren Colenso Semple is a leading researcher in female physiology, and her work debunks a lot of popular myths.

Dr. Lauren Colenso-Semple: 00:15

Many scientists are hesitant to study women because of this unknown influence of the menstrual cycle or hormonal contraceptives on whatever outcome they're studying. Do

Dr. Gabrielle Lyon: 00:28

menstrual cycles really affect your gains? Should you train differently on the pill? And what about the viral trends like cycle sinking and fasted cardio. This is the science women need to hear. Dr Lauren Colenso Semple, welcome to the show. Thank you so much for having me. I am really excited to have this conversation. It is a important one, critical especially now, because it seems as if women are getting much more interested in training, although I don't know you and I have been training probably our whole lives. Yeah, and we can agree that muscle is the organ of longevity, for sure. Let me tell you why I wanted to have you on you come from and your colleagues will be deeply excited. The home of evidence based information, and that is McMaster University. You have a PhD in integrative physiology. You also have a master's in Exercise Science from the University of South Florida, and then a bachelor's in psychology and nutrition. Your research is unique, and it emphasizes female physiology, and with a interest in muscle growth, yes, you've also published and contributed quite a bit to the science, and there are many topics that we're going to cover in this episode, topics that include oral birth control, cycle syncing, which seems to be very popular these days, the training differences between men and women. We're definitely going to cover fasted cardio, and that's just the beginning. Yeah, before we start, I would love to just briefly hear about your background as to how you got interested in such a specific area of science. I

Dr. Lauren Colenso-Semple: 02:29

developed an interest in the resistance training literature and really muscle physiology in general, when I was working as a fitness professional in New York City, and I wanted to get the best results for myself and be the best coach possible for my clients at the time, and when I decided to go back to school and get a master's degree and subsequently a PhD, I really wanted to help fill that gap, because I think all scientists would agree that women are underrepresented in the literature, and what I found out was many scientists are hesitant to study women because of this unknown influence of the menstrual cycle or hormonal contraceptives on whatever outcome they're studying. So my hope in really looking into some of this was twofold. One, we don't know much about the ovarian hormones. We know a ton about testosterone. So do they influence muscle? And two, if cycle phase or hormonal birth control isn't going to influence the outcomes that we're measuring, this can open up so many doors for more scientists to start studying women.

Dr. Gabrielle Lyon: 03:45

It's fascinating that women, I was reading that women were not included, or necessarily included into research until 1993

Dr. Lauren Colenso-Semple: 03:54

Yeah, I think a lot of the foundational studies that we have are certainly in men. I do think the more and more research we do in women, we often find there aren't actually sex differences. But that doesn't mean it's not important to do the work. Were

Dr. Gabrielle Lyon: 04:11

you surprised that there weren't as many sex differences as you thought? Did you go into research thinking, Okay, well, I'm definitely going to respond differently than say, My husband is did you have a preconceived notion of what the variations in training would be and how individuals respond to muscle or their muscles respond to training?

Dr. Lauren Colenso-Semple: 04:34

Looking back? No, because just from a practical perspective of training myself and training men and women over the years, the principles were always the same, and then you just adjust for individual preference and what is sustainable for that person. But I think there, there wasn't anything really that I did as a coach or as a woman. Training that was unique, just because I am a woman, or because I was coaching one,

Dr. Gabrielle Lyon: 05:06

one of the really important aspects of having you on is on your Instagram actually do a wonderful job. A lot of scientists are not very active on Instagram, but you do definitely spend time going in to social media versus science, probably some of my favorite posts of yours, and there is something out there. There was this idea that individuals should work out for each phase of their cycle and switching exercise modalities, or reducing volume or intensity every other week will delay your progress. And I just, I pulled this from your IG, can you tee us up for hormonal phases, cycle phases, the baseline, and then what it is going forward? How do we need to think about that in relation to training.

Dr. Lauren Colenso-Semple: 06:02

So if you have a menstrual cycle, meaning you are not on hormonal birth control, then your hormones start low at the beginning of the cycle. So that's when you are menstruating, and then estradiol starts to increase and peaks prior to ovulation. So ovulation is characterized by a spike in luteinizing hormone. Then during the next half or phase of the cycle, we see a secondary estradiol peak and also an increase in progesterone. So when we think about menstrual cycle phase, it's often describing these different hormone profiles that are shifting, and that either is low hormones, high estradiol, high luteinizing hormone, or high progesterone with moderate estradiol. And the thought was that perhaps one of these hormones would promote muscle growth, or the muscle's response to exercise, and another might inhibit the muscles response to exercise. Would

Dr. Gabrielle Lyon: 07:08

that be? For example, like progesterone, people will say progesterone is catabolic. Is that true?

Dr. Lauren Colenso-Semple: 07:19

It really isn't reflected in the science where this all comes from is rodent model data where you remove the ovaries from a rodent and essentially shut down hormone production. And in some of these models, when they shut down hormone production, the rodent lost the ability to maintain muscle mass or to grow more muscle and that so that's really where the idea came from, that estradiol would be quote, unquote anabolic, and that we should be training harder or at higher intensities during the first phase of The cycle, because that's when you have your highest estradiol peak. But we're making a huge leap from that preclinical rodent model to practical applications for humans. And while rodent data is incredibly important, it's a necessary step for many scientific questions, the purpose of that is to show a mechanism or to generate a hypothesis. We can't jump the gun and assume that the results of that much simpler model will apply in a more complex, dynamic human model,

Dr. Gabrielle Lyon: 08:41

when in and in a rodent model, one also has to recognize that they are in sterile environments. Is not necessarily reflective of how humans live. You can control their diet. You can control everything absolutely.

Dr. Lauren Colenso-Semple: 08:57

And there are many differences when it comes to the reproductive cycle. Men, metabolism, lifespan, they're not human. Hair Growth,

Dr. Gabrielle Lyon: 09:07

yeah, they're definite, yeah, definitely not human. In the literature, is there evidence that women should train related to their cycle

Dr. Lauren Colenso-Semple: 09:21

there isn't and this is one of the questions that I spent several years answering, is this what you did? Your my ideas on what was that? Yeah, so I looked at cycle phase and muscle protein synthesis in response to exercise. And we used deuterium, which is a metabolic tracer, to really look at what is happening in each of these distinct phases. We used a within subject design, meaning each woman was tested during the high estradiol phase, that late follicular phase, and. Also during the high progesterone moderate estradiol phase, or the mid luteal phase. And I say this because a lot of the past literature when it comes to menstrual cycle is considered low quality because the scientists didn't truly track cycle length or ovulation timing, and therefore phase length, and didn't necessarily measure blood hormones. And then fascinating.

Dr. Gabrielle Lyon: 10:29

So this is this reminds me of my interview with Dr Abe Morgentaler, where they believed it was one person actually that believed that testosterone caused prostate cancer, and they went back and they looked at the literature, and it was first in rodent models and then the human studies, that it was one person, and for decades, they believed that testosterone caused prostate cancer, so they castrated men based on never going back and re examining the

Dr. Lauren Colenso-Semple: 11:04

evidence. That's a huge problem, of course, that

Dr. Gabrielle Lyon: 11:08

every guy ever Yeah, yeah.

Dr. Lauren Colenso-Semple: 11:11

I think when we look at the idea of cycle sinking, which has become trendier and trendier over the past few years when we look at what that prescription is, it's often, hey, you should be doing higher intensity or just focusing your resistance training for half of your cycle and then doing something lower intensity or gentle stretching, Light yoga during the the rest of your cycle, which essentially cuts your volume in half. And so just hearing that and knowing what a sound resistance training program looks like, that's going to impair your progress, because you're doing way less total training volume.

Dr. Gabrielle Lyon: 11:58

And you'd mentioned earlier before we started recording, that oftentimes there's a kernel of truth. Is there a kernel of truth? And you know, every woman listening is probably like, depending on her age, when she gets her period, it definitely can tank, especially when you're younger, it seems like there's a lot more variation in the cycle. And when I say variation in the cycle. I mean intensity. Let's say an individual, when you know lots of my patients in their 20s have back pain, bad cramps, all of these things that seem to resolve over time, one would anticipate that perhaps a lighter week would be reasonable for the way that they feel, and that might not necessarily show up in in the literature or the science, but is there a kernel of truth that, depending on the phase, there is an influence when estrogen is low or when testosterone is higher, or any of these hormonal variations?

Dr. Lauren Colenso-Semple: 12:59

No, so I really like to distinguish between is a hormone profile doing something for us in the way that we respond to exercise, versus as human beings who feel more or less ready to train on any given day, perhaps because you're experiencing menstrual symptoms, perhaps for another reason, like you're fatigued, you know you didn't sleep well the night before, etc. You're going through a high stress period at work. There are many reasons why you might have an have an off day, and so I think every training program should include a component of auto regulation. So if you are having that day where you're just not up for the higher intensity training. You should feel free to swap out an exercise or adjust the volume, or even don't go to the gym that day. That's completely fine. The problem with these cycle sinking type models is that they're encouraging women to plan to feel worse during a given period, and just the psychological implications of doing that can kind of set you up for worse performance, because I've planted that in your mind. And so we need to really separate the being reactive in response to how you feel versus these pre planned changes based on theoretical hormone profiles.

Dr. Gabrielle Lyon: 14:28

Do we have randomized control trials? Is it difficult to do randomized control trials with women and their cycle? It's very difficult. The reason I'm you're laughing and I'm laughing and I'm laughing is because I know that you have certainly looked at

Dr. Lauren Colenso-Semple: 14:43

this. Yes, so I did, I did one, and it's very different, by the way, there are only there are a handful. And like I said, the in many of these, they just assumed every woman had a 28 day cycle and ovulated in the middle of that cycle, meaning you had. An equal length follicular and luteal phase, when, in fact, normal cycles can be as short as 21 days, as long as 3637 days, and ovulation can occur anytime in there. So if you're somebody even who's tracking your cycle on an app and it tells you when you're ovulating, those apps are assuming a correlation between cycle length and ovulation timing that actually doesn't exist. So in order to do this work properly, you have to track cycles, many cycles, you have to test ovulation, and you have to measure blood hormones. Because if we're making a conclusion at the end of the day that some outcome occurred due to variations in hormone levels, we need to have measured those hormones, and so that's why I say some of these studies were were lower quality. But to your point, it is difficult to do this work because there's so much variability to

Dr. Gabrielle Lyon: 15:57

your knowledge thus far, is there any data that would support cycle syncing. And let's talk about outcomes that are meaningful for us, outcomes, I think that we both agree, are strength, hypertrophy, endurance, all things that are valuable in a comprehensive program, there's

Dr. Lauren Colenso-Semple: 16:16

a great meta analysis published by Kirsty Elliot sale, who looked at exercise performance, they didn't find any meaningful effect in one phase or the other. The work that I've done looked at actually how the muscle is responding to exercise. So we measured muscle protein synthesis and breakdown at rest and in response to resistance training. Biopsy muscle, yes, and there were and there were no difference, no differences, and again, measuring them within the same person. So that does remove some of that variability that I was referring to sitting

Dr. Gabrielle Lyon: 16:50

down talking to Dr Lauren, as you can tell, there is a lot of confusion in general, and confusion of what to put into our body. Fish oil is one of the supplements that I always recommend. There is good data for mood improvement, inflammation, muscle health, heart health, and when I was doing a fellowship in geriatrics, omega three fatty acids, they were always on the list of recommendations. I won't just use any fish oil, and this is why I love peorias 03 ultra pure fish oil, it is third party, tested and certified by the clean label project. And IFOs, just like when we talk about good manufacturing practices, every batch of peorias 03 ultra pure fish oil and all of their supplements are tested against more than 200 contaminants, with all of their results published online, take a great source of Omega three is important, but also worrying about if there are harmful chemicals in it is just as important. And I trust peoria's 03 ultra pure fish oil, so much that I use it with my kids. And I worked out a deal with Peoria on this 20% off site wide. That even applies to already discounted subscriptions, you'll get almost a third off the price. But in order to get this offer, you'll need to go to my exclusive URL, peori.com/dr, Lion, and use my promo code, Dr lion. That's P, U, O, R, i.com/dr lion. Do you think that there are differences in the muscle or in the environment with those ebbs and flow? My gosh, this is my second podcast for the day. I do that again. Do you think that there are differences that perhaps, haven't been measured meaning, let's say edila levels are high and there are receptors in the muscle, estrogen receptors in the muscle. Do you think that, potentially, based on fluxes in hormones, that there are outcomes that are meaningful? Because it would make sense, because there are, again, there are receptors in muscles or testosterone, there's androgen receptors. It would make sense that the influence would be there. Maybe we just aren't measuring it appropriately, or maybe not looking at the right thing.

Dr. Lauren Colenso-Semple: 19:15

I think when it comes to what is meaningful, we're looking at adaptations that occur over time. So when we think about the time in which estradiol peaks, for example, we're talking about a number of days. And so the idea that that would be so powerful that it would somehow be a game changer for hypertrophy or for performance is sort of hard to wrap your head around, because, again, we're looking at this one element of a much more complex physiological system. I think

Dr. Gabrielle Lyon: 19:52

that makes a lot of sense. I personally have not seen any good data that would support cycle syncing, and it's just been interesting. To see so much on social media, or so many individuals thinking about and using it, I suppose, if an individual is training for the Olympics, I think it would be detrimental. I mean, because can you imagine if the Olympics falls on the first day of your period?

Dr. Lauren Colenso-Semple: 20:21

Funny, you should say that because Olympic medals have been won in every cycle phase. So you'd also think that we would see a trend in that retrospective analysis. What about

Dr. Gabrielle Lyon: 20:31

oral contraceptive use? Can you tee up? And I was actually looking I saw numbers anywhere from 20% of women ages 19 to 25 were on hormonal birth control? I saw some literature that actually suggested 50% these are very common medications. They are also, I want to say, not without risk. There are various different types, whether it is estrogen or if someone can't use an estrogen, there's a progestin. Birth control. Can you talk a little bit about birth control use and what is being said on social media, and how we can think about their use from a performance impact.

Dr. Lauren Colenso-Semple: 21:18

If you are on a hormonal contraceptive. You don't have a menstrual cycle, so those fluctuations that we've been discussing, those aren't happening. It suppresses that endogenous hormone production and introduces these synthetic hormones. And the concept that this would affect your performance or your exercise induced adaptation is really coming from the same line of thought that the concept of phase based training or cycle synching comes from. But you'd think, if you aren't getting that estradiol peak anymore, then oh, perhaps this would be detrimental, or because you're introducing a steady dose throughout the month, then maybe it would be advantageous. So there have been dueling hypotheses, if you will. And when we look at the data, there's a recent meta analysis that came out last year. I believe oral contraceptive use compared to naturally cycling individuals, there was no influence on hypertrophy, strength or power. Yeah,

Dr. Gabrielle Lyon: 22:28

it is fascinating in the literature. It doesn't seem like there's been a ton of data, but some studies show that oral contraceptives, this combination, estrogen, progestin, may blunt muscle gains, but then, you know, you look at this other study. So this is Elliot sale, who you had quoted. And you know, this was a 2020, study. It showed that women on the pill gained 40% less muscle, but that had not been replicated, and this was over 10 weeks. And it just seems as if, overall, it doesn't seem to have an impact on muscle protein synthesis. From what I can tell,

Dr. Lauren Colenso-Semple: 23:10

no, there are some studies showing that it was slightly beneficial for hypertrophy, and others that show it was slightly disadvantageous for hypertrophy. But these effects were so small that when you look at the literature as a whole, you would just conclude that this could be due to individual variability in response to training in general, or something that is not clinically significant or practically relevant?

Dr. Gabrielle Lyon: 23:41

That's a very important point. We don't typically look at papers in isolation. It should really be thought of as a collective body of knowledge. It's a collective consensus. Has this information been repeated in various labs by various people, and we definitely are not necessarily seeing that. Do you think that there is an influence on oral contraceptives and performance? Is there anywhere because you're making women essentially an ovulatory

Dr. Lauren Colenso-Semple: 24:17

I don't think we have evidence to suggest that ovulation is required for maximal performance, and in reality, many, many high level athletes are on an oral contraceptive, if only for the kind of convenience of being able to plan around your Training, around when the scheduled withdrawal bleed is going to occur. And I think your point is really well made, that we never want to put too much weight in a single study, because science always builds on the science that came before it, and one study is never going to give us all the answers. I know people sometimes get frustrated by science because they think, Oh, these scientists are changing their mind, or last year it was this, and this year it's that, but it's actually good news when we get more and more and more data, because it either increases our confidence in what we thought was the case or starts to shift our opinion, or even if it's just in a more nuanced way, because we can't answer every question in one trial, we start to say, hey, well, what about this outcome, or what about this population? And then we expand it out from there,

Dr. Gabrielle Lyon: 25:34

yes. So this is so this paper is menstrual cycle, hormones and oral contraceptives, a multi method systems physiology based review of their impact on key aspects of female physiology. And this is a it's a wonderful paper, and it's a comprehensive review. It evaluates how the menstrual cycle phases and oral contraceptives can influence female physiology. Do you think it matters the training status of the individual. For example, if a woman is highly trained, it seems as if her training will trump everything, whether it's, you know, menopause changes, whether it's any kind of flux and hormones, because that individual is so well trained versus an untrained woman, who might be, I don't know, more susceptible to other stimulus because she's not pushing her muscle in the way that say a more well trained individual is,

Dr. Lauren Colenso-Semple: 26:38

I don't think there would be an anticipated difference of oral contraceptives between those two individuals. I think it is important to note that when you think about on an individual basis, some women will start an oral contraceptive and just not respond well to it. They'll have some symptoms that either resolve on their own, or they just realize, hey, this isn't a good fit, and they need to switch to a different one. And so it is possible that due to the response to that particular oral contraceptive in that particular individual, that they start to feel worse, and then subjectively, performance takes a hit. But that's not the same as saying, because I introduced a new hormone profile through a hormonal contraceptive, I am now primed for better or worse exercise performance.

Dr. Gabrielle Lyon: 27:31

And you actually published a wonderful so your first author on this paper in the Journal of Physiology, which is a high impact journal, and this was menstrual cycle phase does not influence muscle protein synthesis or whole body myofibrillar proteolysis in response to resistance exercise. And this was published December 2024, and the reason I bring up this paper, Well, number one, it's well done. And number two, you are speaking from a place of actually doing the research. Can you highlight the hypothesis of this paper, and what the outcome is?

Dr. Lauren Colenso-Semple: 28:08

This was really to test this idea that that high estradiol phase is quote unquote anabolic, or the high progesterone phase is quote unquote catabolic, because if that's the case, it should be reflected in muscle protein synthesis over the six day period in which it was measured. And we don't see a difference between muscle protein synthesis or muscle protein breakdown in either phase at rest or in response to exercise.

Dr. Gabrielle Lyon: 28:36

Were you surprised by your results?

Dr. Lauren Colenso-Semple: 28:40

I went in really open minded, but the more I did the work and measured the hormones and realized the variability in not only the timing, but also the magnitude of the fluctuations, I would also think if there's something to this high estrodo estradiol, or if there's something to this high progesterone, we would see some relationship between people with the highest estradiol peaks being the most muscular. Yes, we don't see any relationship at all.

Dr. Gabrielle Lyon: 29:12

That is interesting, because a lot of the conversation around hormones are they're in isolation, and you will hear, well, estrogen, women lose muscle during menopause because their estrogen declines. And that actually is not what happens, which will get to changes in body composition during menopause. But what I actually loved about this paper you guys use, did you measure d3 creatine?

Dr. Lauren Colenso-Semple: 29:43

We did. We used d3 creatine to measure muscle mass. That's

Dr. Gabrielle Lyon: 29:48

incredible. Can you talk a little bit about that? Because most individuals are not using d3 creatine, and I think it is really important. And honestly, I wish we could use. In clinic. Can you share a little bit about how you looked at body composition and why you decided to use the three creatine

Dr. Lauren Colenso-Semple: 30:06

what most papers will use when we're looking at lean mass, and sometimes people start to use lean mass and muscle interchangeably, is a DEXA scan. And so a DEXA can give you your bone mineral density. It can give you your fat mass, and then it gives you everything else. And that's what we would say is, is fat, free mass or lean mass. But it doesn't just include muscle. It also includes, you know, organ mass. It includes body water. It's everything that's not fat and bone. So clearly it's going to overestimate muscle and it's not a distinct measure of muscle, d3 creatine is as best as we have, the most direct measure of muscle mass, and it's non invasive. We're measuring it in urine. So my hope is that it will become more widespread. Can

Dr. Gabrielle Lyon: 30:59

you just talk briefly about what d3 creatine is measuring and how it's working in the body.

Dr. Lauren Colenso-Semple: 31:08

It's measuring the excretion of Creatinine in the urine, and so that is the marker for muscle mass, and we're using this stable isotope tracer that allows us to look at kind of the input and output the same way that we use the deuterium to measure the accumulation of the amino acids in the muscle biopsy itself. Now

Dr. Gabrielle Lyon: 31:31

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Dr. Lauren Colenso-Semple: 33:28

it's also unfortunate, especially on an individual level, if you're trying to track lean mass over time with DEXA, there's often just a lot of noise in there, and it can be influenced by your hydration status and fetter fasted state, things like that, and so it's not great for tracking those changes over time. Were you

Dr. Gabrielle Lyon: 33:47

hearing that people were concerned about using oral birth control? Is there a belief out there that it could impact negatively people's performance, or was it the opposite? Were people believing that it could improve performance? What was kind of the controversy around it?

Dr. Lauren Colenso-Semple: 34:03

I think when I started doing this work, it I wasn't really hearing any positive or negative sentiments about this. But now online, I see more and more people using this kind of fear based messaging that you shouldn't be on an oral contraceptive because it's going to interfere with your performance, or because your adaptations to exercise will be somehow inhibited. And that's a really problematic message that I think is not evidence based. And I hope we can get away from yeah

Dr. Gabrielle Lyon: 34:35

and listen, if you're someone who uses oral contraceptive, where we are certainly not saying they are good or bad, but from this perspective of impacting performance and body composition at the level of muscle, it doesn't seem to have an influence. The other thing I will say is that oral contraceptives can irreversibly increase something called sex hormone binding globulin, and that is. Thing that, again, not necessarily a problem, but just to be aware of. And of course, there are other risks with taking anything. There's no free lunch but the and when I say perhaps if individuals are older or there can be increased risks of clots, but what we can say is that it doesn't seem to affect and also pregnancy if you're not taking it. But one thing seems clear is that it doesn't affect muscle protein synthesis over time, which I think is fascinating,

Dr. Lauren Colenso-Semple: 35:31

or strength or power adaptations, as we've seen in the literature today.

Dr. Gabrielle Lyon: 35:37

You know, it makes me think about the idea that men and women should be training differently, because what we're really talking about is, do these hormones influence men or women differently, and should they be training what statistics can you give us in terms of men strength, or a man's strength versus a woman's strength, or the level of hypertrophy that either can obtain?

Dr. Lauren Colenso-Semple: 36:06

Well, I think there was a long thought perspective that women can never gain as much muscle as men, and that is what my husband tells me, because of this huge difference in testosterone levels. But what we've seen over the years is actually it's about your starting point. So men experience a surge in testosterone during puberty, in which they also experience an increase in muscle size and muscle strength. So meaning, if you take two adults, one untrained man, one untrained woman, the man will be more muscular and stronger if you do a performance test, let's say a, you know, bench press test, a leg press test. But on a relative basis, the amount of muscle and strength that you can gain again relative to your starting starting point is the same. So it actually tells us that while testosterone is really important to give you that initial boost, that women aren't getting the relatively speaking, the gains are the same,

Dr. Gabrielle Lyon: 37:15

which is, I think, something that is really misunderstood. Yes, what about this size? Can women get as big as men? Is it relative to body weight? What do we know about cross sectional area?

Dr. Lauren Colenso-Semple: 37:29

Well, again, it's all relative to your starting point. So if at the beginning, you are a bigger human, and you have more muscle than and you do a challenging, progressive resistance training program, then, on an absolute basis, you're going to be bigger at the end as the person who was, who was a woman who was smaller from the beginning. So we're speaking about relative to your starting point, but generally, on an absolute level, the men will be bigger and stronger than the women. Yeah,

Dr. Gabrielle Lyon: 38:01

I'm looking at this statistic, and this was, on average, men have about 36% more skeletal muscle mass than women, with a greater difference in upper body compared to lower body. It says upper body 40% less muscle in women, again, but this probably isn't necessarily men, and this is, I can pull up where this is from, but this is, you know, what I'm hearing you say is, this is really just about the size of the human and where I got these numbers. This was from Applied Physiology. And this was just looking at comparison of regional and whole body skeletal muscle mass measurements, it's probably more so the size,

Dr. Lauren Colenso-Semple: 38:44

size is definitely, definitely a factor, but also that testosterone during puberty is going to give men that advantage. Just as a starting point, can

Dr. Gabrielle Lyon: 38:57

we talk about the variations in training? There is a lot of information floating out there about men and women needing to train differently. And with that, I will also say that there is information that the muscle fibers are different, so men have more type two muscle fibers, which are the bigger, bulkier fibers, versus type one fibers for women making them better at endurance type Sports. Is there truth to that? And should women and men be training differently?

Dr. Lauren Colenso-Semple: 39:28

There's some data to suggest there are some fiber type differences. We need to be a bit careful about extrapolating that to all muscles, because when we take a biopsy, we're only taking it. That's a really good point. You know, a specific muscle and But importantly, fiber type proportions shift in response to training. So if you have somebody who's an elite endurance athlete, their fiber type composition is going to. Look different than somebody who is an elite Olympic weightlifter, because the training in and of itself, is producing divergent adaptations. So the idea that this would drive our training programs misses the mark for me, because I think we should be designing our training program in order to meet the goal, whether that's overall health, or if you are running a marathon or if you do want to do a power lifting competition, your training is going to look different, but that doesn't necessarily differ because of your biological sex. That's just a factor of individualization, which I think is important for any training program.

Dr. Gabrielle Lyon: 40:42

What about when, you know, maybe last year, the year before, there was a lot of, I shouldn't say a lot, but there was some men competing in women's sports. I don't know exactly how to say it, but there was a story of the swimmer.

Dr. Lauren Colenso-Semple: 41:01

Do you remember that there has been some controversy around transgender athletes in sports? Yeah,

Dr. Gabrielle Lyon: 41:08

so would it be? Do we have a sense of why it seemed like the transgender females would be able to outperform the biological female,

Dr. Lauren Colenso-Semple: 41:22

if you go through puberty as a male.

Dr. Gabrielle Lyon: 41:25

Okay, so this is again, going back to

Dr. Lauren Colenso-Semple: 41:29

testosterone, yes, because this actually there. There's a paper on this that that measured this post transition, and you do retain some of that advantage even after you undergo the hormone therapy during the transition. So

Dr. Gabrielle Lyon: 41:45

that's, I mean, that's interesting. Yeah, where do you think science needs to go? And when I say that, how can we get a sense of so the there's an overwhelming amount of evidence that seems to point to that having a good training program, and we should talk about what that looks like, and we should talk about what that looks like for strength versus what that looks like for hypertrophy. Because I will say, at McMaster University, you guys do, and have done some of the best studies that I have seen for older individuals, but there seems to be an overwhelming amount of evidence that it is not necessarily sex specific, but it is good training practices. Can you talk a little bit about what good training practices are?

Dr. Lauren Colenso-Semple: 42:31

We need to do training that is challenging and so it needs to be close enough to failure. So if you think about the number of reps you could do and you couldn't possibly do another one. That's failure. We should probably be training one to two repetitions shy of that so we know we're getting a good stimulus to the muscle. And then we need to progress over time. So whether that's increasing the weight or the load, whether that's adding a repetition using the same weight, whether that's adding a set just over time, you start to do a little bit more, and that continues to apply an appropriate stimulus. And this works for younger individuals, older individuals, men and women. Do

Dr. Gabrielle Lyon: 43:16

you think that there's a difference in response? Some people are better responders to exercise versus others. You know Nicholas bird, he had an interesting paper come out talking about how obese individuals have more of a blunted response. I don't know if it's been replicated. Do you think that there is interpersonal variation to response to training. We definitely

Dr. Lauren Colenso-Semple: 43:41

see this with older individuals, that the degree to which you'll respond to resistance training is probably going to be less than the degree to which you would respond in the younger years. That said, there are people who, in studies, are training in their 80s and still gaining some muscles, still getting the benefit. So I think the good news is it's never too late to start. Yeah,

Dr. Gabrielle Lyon: 44:06

I think that that's a really great point. Do we know thinking about how now the hormones so an older individual who is not on hormone replacement, assuming has very little estrogen do we know what estrogens impact is on muscle tissue. Do we know what the sex hormones influence is?

Dr. Lauren Colenso-Semple: 44:27

It's really difficult to pinpoint a specific hormones mechanism of action in a practical way, because these hormones work together. They are fluctuating together, and when we are going through the menopause transition, for example, you can see really erratic fluctuations in hormones. It's not just your estradiol, it's also progesterone, it's also luteinizing hormone. And so people tend to. Want to just talk about estradiol, but I think that's missing the bigger picture. That said we see people who age start to lose muscle mass and lose muscle strength. We see this in men and women, and we also see physical activity begin to decline with age in men and women. So I don't think we have the data to suggest that there's something about estradiol, in and of itself, or any other hormone for that matter. Testosterone,

Dr. Gabrielle Lyon: 45:29

though we know, has anabolic properties for muscle protein synthesis,

Dr. Lauren Colenso-Semple: 45:34

we do, but the fact that it's the hormones are declining is that the reason that you're losing muscle, or is it another function of aging? Because we can't tease out those differences in humans, the aging is happening along with the gradual hormonal decline. So you can potentially point to one mechanism or another, but to isolate the hormones and say it must be that not necessarily the case. Do

Dr. Gabrielle Lyon: 46:05

we know what the say the influence of and again, I suppose this is more theoretical. We know that resistance training might increase androgen receptor density in skeletal muscle. I think there's good data to support that testosterone increases muscle protein synthesis is anabolic in nature. Is there something that we could say about estrogen? Just trying to understand from my own perspective, because I have seen the literature all over the place, sometimes you'll see estradiol as anabolic, and then in other literature, you will see that it is has very little anabolic effect. When

Dr. Lauren Colenso-Semple: 46:45

we go back to the rodent model that I mentioned earlier in the conversation, where you remove the ovaries and you shut down hormone production, there was a study where they were able to reverse the muscle loss with a synthetic estradiol injection into the rodents, and so that is hypothesis generating for the argument that perhaps there is something that the absence of estradiol is a problem for muscle. That's a good hypothesis. But when we look at a meta analysis of women who are on hormone therapy, and there the effects on muscle. We're not seeing it pan out. And so it wouldn't be the first time that we see something that looks promising or exciting in rodents that just doesn't pan out when we actually look at humans. Yeah, it's

Dr. Gabrielle Lyon: 47:36

interesting, because men also have estrogen but, you know, I have looked in the data, and I would think, in my mind, that the influence of estrogen would be different on a man versus a woman, on their skeletal muscle. And you don't necessarily see that, and that's what I think is so fascinating, because I'd love to understand the actual influence of estrogen or estradiol on skeletal muscle. I don't think that we have a clear answer. I was hoping you could give me one as to what the actual influence is.

Dr. Lauren Colenso-Semple: 48:10

Yeah, we don't really have a clear answer. And again, it's really difficult to tease this out in humans. It's much easier to try to do the I mean, I'm not knocking the rodent study. It's just easier to control that environment and then say, let me remove this and add this and perhaps look to a mechanism. But again, we're trying to look at a simple model and apply it to a complex, dynamic model. And when we think about women who are aging and either on hormone therapy or not. Many, many of them are not resistance training. Many, many of them could use some improvements in their diets. And so we haven't seen the study yet that looks at people who are resistance training and eating adequate protein versus people who are on hormone therapy versus a combination of all of the above versus none at all, and see and then we could maybe tease out if there's an additive effect.

Dr. Gabrielle Lyon: 49:10

Yeah, I think additive is the key word. I worked on some of the early studies of postmenopausal women. It was some of the first of its kind at the University of Illinois, where they looked at body composition and died in exercise. And these women were not on hormone replacement, and they were able to move their body composition just by managing exercise and nutrition Absolutely. And so I think the influence of hormones outside of testosterone, I do think testosterone and other anabolic agents seem to have a bigger impact on muscle strength and size, but when it comes to things like estradiol or progesterone, again, I agree with you. I think that is an additive effect. What about progesterone or progestins in skeletal muscle? So it's considered a steroid. Own that is mostly known for its role in menstrual cycle and pregnancy, but it seems to have systemic effects, whether it's anti inflammatory, again, it's a very complex system. Yeah, do we have an indication of what it does in skeletal muscle at all? No,

Dr. Lauren Colenso-Semple: 50:21

we really don't. So many of the claims about progesterone and skeletal muscle are kind of assumptions that are extrapolated from this. Estradiol is anabolic type argument, and there's some data to show that there are progesterones progesterone receptors in skeletal muscle. But some people even contest that. Lauren

Dr. Gabrielle Lyon: 50:43

and I have been talking all about muscle health, and I think something that's often overlooked, and maybe the next frontier of health is going to be balancing circadian rhythms, and those are the light and dark cycles. Light is one of our greatest anchors for energy, for how we sleep, and arguably how we train you may have seen my family and I using red lights. We use it all infrared heating mats. We use red lights in the evenings. And the reason we do it is because it helps manage our circadian rhythms. And the red light that we use is bond charge. And bond charge is a holistic wellness brand with a huge range of amazing products to optimize your life in every way. What I love about bond charge is it's founded on science, but inspired by nature and the products allow us to balance our highly industrialized lifestyle, which creates all kinds of dysfunction under unnatural bright lights. Rather than being outside all day, these products really offer solutions. Again, I use the lamp, the red light lamp. As soon as it gets dark outside, I turn down the overhead lights, and then I use a larger panel, 10 to 20 minutes each day. Bond charge has the lowest EMF on the market, and the quality, the quality is incredible. They have 12 month warranty on all red light devices. Go to bond charge.com/dr lion and use the code Dr lion to save 15% off. That's B, o, n, C, H, A, R, G, e.com, and use the code Dr lion. Are there indications in rodent models of what progesterone does

Dr. Lauren Colenso-Semple: 52:25

not in rodent models, more so not progesterone in rodent models, more the estrogens in rodent models. And so there's some data to suggest there might be a regulatory role of estrogens and satellite cells, because there's a group that found estrogen receptors on satellite cells specifically and just for the listener. A satellite cell cell is a muscle stem cell, and so thought to be involved in regeneration, recovery from muscle damage, we see an increase in satellite cell proliferation and differentiation when we do a particularly damaging exercise and the down regulation of the estrogen receptors also seem to kind of deplete the satellite cell pool. So that generated a hypothesis that there might be something to estradiol and recovery from training, or your ability to train more frequently. Those were kinds of but again, you're making a big jump there from that simple model to real people training.

Dr. Gabrielle Lyon: 53:35

Yeah, and you know what? It might not even be the muscle. So I've had another orthopedic surgeon on Dr Jocelyn, and what she sees is that when estrogen declines, this is when people will present with frozen shoulder, this is when we will see tissue injury, tendon tissue injury. So it's not muscle per se, but it's tendons and the other challenges with mechanics, which I think is very fascinating,

Dr. Lauren Colenso-Semple: 54:01

sure. I mean, when you think about resistance training, you are never working muscle in isolation. It is in combination with connective tissue and bones. Yes,

Dr. Gabrielle Lyon: 54:11

so that is, that is one role. It seems that estrogen replacement therapy seems to have an impact, and not necessarily on skeletal muscle, but certainly on tendons. Let's talk a little bit about why hypertrophy happens, just for the listener so they can make their own decision if they should train differently, right?

Dr. Lauren Colenso-Semple: 54:37

So hypertrophy occurs when the balance of muscle protein synthesis exceeds that of muscle protein breakdown over time, and then we see an increase in cross sectional area of the muscle, and we see hypertrophy from low load high rep training. Uh, things like 20 reps, for example, we see hypertrophy from a high load, low rep training, something like a set of five. And what really drives hypertrophy is the stimulus that you're putting on the muscle, driven by mechanical tension that then is able to increase the size of the muscle, and there's an abundance of data at this point to show that this can be accomplished in a variety of loading schemes and intensities.

Dr. Gabrielle Lyon: 55:32

What you're saying is it doesn't matter how you stimulate the muscle, whether you're doing high load, low rep, you

: 55:41

name it. Machine, free weight, heavy

Dr. Gabrielle Lyon: 55:45

lifts. What about lifting? So we're really talking about hypertrophy, which, in my mind, hypertrophy is increasing the cross sectional area of the muscle. Would you agree with that? I would agree. Okay, there are a million different ways to get that done. It's assuming that the stimulus is enough to provide adaptation, yes.

Dr. Lauren Colenso-Semple: 56:05

And if you want more hypertrophy, you probably need to do more over time, so we would say increasing training volume. And there's various ways that you can do that as well.

Dr. Gabrielle Lyon: 56:17

There are a lot of discussions about how women need to lift heavier as they age. I really thought that was true for a very long period of time, and I don't know if it's true if it's a menopausal phase. And again, this is, was what I wanted to believe. And then I started looking at the data many years ago, many, I don't know, five plus years ago, coming out of Stu Phillips Lab, which is yours McMaster University, and he published some of the first, I mean, they just really well done papers about how and I think maybe it was way over five years ago, I was in My geriatric fellowship at WashU, and we were putting individuals through training, and the data showed that you could get just as much hypertrophy with low load, so very lightweight and then a million reps. Yeah,

Dr. Lauren Colenso-Semple: 57:15

this is something that the fitness community has changed their mind about over the years in response to this data, because it used to be thought that there's this strength endurance continuum, and that if you want

Dr. Gabrielle Lyon: 57:29

to get schoenfeld's paper the strength right, and in every personal

Dr. Lauren Colenso-Semple: 57:34

trainer course, they would teach you this as well, that if you want to get strong, you need to be doing those high loads, low repetitions. If you want hypertrophy, you should be doing kind of moderate repetition, eight to 12, something like that. And then if you're doing anything higher than that, it's just muscular endurance, and it's not going to affect hypertrophy. And our understanding of that has really evolved, and it looks like even doing as many as 30 reps is just as good for hypertrophy. Obviously, there's reasons why you might do that or not do that in a given exercise, but the idea that we have that level of flexibility, I think, is really important. So

Dr. Gabrielle Lyon: 58:12

what is the amount of time that an individual should be training an individual who is untrained? Let's say there's an untrained, 55 year old woman listening to this podcast who wants to embark on a hypertrophy journey,

: 58:31

going from doing nothing to doing anything. I knew you were gonna say that my friend is

Dr. Lauren Colenso-Semple: 58:35

huge. So even if it's 20 minutes a week, it will make a difference. I don't love to think of it in time, because there's different ways that people can structure their training to make them more or less time efficient. So for example, you could do a program with straight sets, where you're doing a set and then you're resting for a couple minutes, and then you're doing another set and then you're resting for another couple of minutes, and that is is an effective way to train but it's not necessarily the most time efficient, but you can do things like circuits or super sets where you're doing one exercise and then pairing that with another exercise, and that can kind of give you more bang for your buck from a time efficiency perspective. So I think a great place to start would be two days a week, even just 30 minutes, and then you can move up from there, as works with your schedule. But what we do see is that the small dose makes a huge difference.

Dr. Gabrielle Lyon: 59:34

Is there a minimum amount of reps and sets that someone should think about doing.

Dr. Lauren Colenso-Semple: 59:45

No because, well, if you're doing one repetition,

Dr. Gabrielle Lyon: 59:49

but right, you might see, okay, so it's 20 to 30 reps. How many sets? I mean, I don't know. Again, I don't know where the data is in terms of, it's. Challenging, because research is really meant to provide answers for populations. It's not

Dr. Lauren Colenso-Semple: 1:00:05

an individual training prescription, right? And that

Dr. Gabrielle Lyon: 1:00:09

is a challenge. Maybe you want to talk about that, because it seems like it's something that you've certainly thought about. Yeah,

Dr. Lauren Colenso-Semple: 1:00:15

I think sometimes people will go to a paper and say, This is how much volume I should be doing. You know, I need to be doing 10 sets per muscle group per week, because Brad schoenfeld's paper said so and so. I think it's important.

:: 00:29

This is true, right? Yeah, you know, those

Dr. Lauren Colenso-Semple: 1:00:31

are designed to test, in some cases, an upper limit, or in some cases, comparing one type of training program to another, and it's reporting a group average. And so what you will be able to do sustainably is not necessarily something that is going to come from the data. The data is a good place to start in that if you're doing two sets of a few exercises and making some progress, then you're putting on muscle. You are adapting, but we will need to do a little bit more if we want to adapt further. But the idea that you need to be tied to doing a specific repetition range, or everyone must do these exercises. That's not the case, and that, I think, is a really important message, because when people put out there that women must do this or women should not train like that, it creates more barriers, and, in some cases, discourages people from engaging in exercise. And it's not that everybody's exercising and they're doing it wrong. It's that not enough people are exercising at all, right?

Dr. Gabrielle Lyon: 1:01:46

You mean the 50% of the population that's not training, or the 73% that's not meeting both the resistance training plus cardiovascular so that means the majority of people are not doing much of anything. Yeah, what about this idea of fasted training and just some of the nutritional aspects of what is important for body composition. I personally have trained fasted my entire life. There was one period of time in which I didn't train fasted. Can you guess when that is during pregnancy? That's right. That's exactly right. I wanted to get pregnant, and I decided that, for whatever reason that I was gonna start to have breakfast, maybe I was going to lower and don't laugh at me, but this idea of a cortisol response, so when your blood sugar goes low, you'll increase your cortisol. There just seems to be more ebbs and flows with blood sugar regulation, and I decided, You know what, I'm going to suck it up. I'm going to have breakfast. And then when I was pregnant, I did not train fasted. There seems to be lots of information out there in terms of fasted training, and both the fasting part, and then women eating post exercise. So I would love for you to talk a little bit about fasted training cortisol. One of the biggest things that I'm hearing is that fasted training increases cortisol. Is that what you're hearing? Because I definitely get a lot of questions on that and that somehow fasted training will affect muscle mass. Yes,

Dr. Lauren Colenso-Semple: 1:03:27

the message that's been put out there is that fasted training will decrease muscle mass and potentially increase body fat accumulation, and the culprit of that is cortisol, or sort of low energy availability in general. So we can break this down, but this is an interesting one that's kind of resurfaced, and especially for women. About a decade ago, everyone thought fasted training would be better for fat loss. And that is because when you acutely exercise in the fasted state, you see more fat oxidations. You're using more fat as fuel and so, and it was a reasonable hypothesis to say, oh, therefore I'm going to lose more fat, or lose fat more efficiently if I do this fasted cardio. And so all the body builders started doing fasted cardio,

Dr. Gabrielle Lyon: 1:04:23

and then lay Norton came along. You can edit that out.

Dr. Lauren Colenso-Semple: 1:04:29

What we see is that it wasn't actually the case. It didn't pan out. Just because we saw that acute response doesn't mean that it's better for fat loss. So now interestingly, we're seeing the opposite argument, the idea that fasted training would somehow be worse for body composition, that you're going to lose muscle or that you're going to gain body fat from fast food training. And there is not data to support this. It's true that cortisol. Normal increases when you wake up. Cortisol is highest first thing in the morning. It's also true. You want that correct to be this is healthy and normal. Cortisol operates on that circadian rhythm, so highest in the morning fluctuates throughout the day, and low in the evening, before you go to bed, sitting

Dr. Gabrielle Lyon: 1:05:19

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Dr. Lauren Colenso-Semple: 1:06:44

And it's also true that cortisol increases with prolonged fasting. It's also true that cortisol increases in response to exercise. What's not true is that any of this is a problem and that we somehow need to intervene or worry about pre workout nutrition in order to change any of this or fix any of this. All of this is perfectly normal, and when we look at human subject data in women, there's two studies, one from Mardi Caballo slab, another from Brad Schoenfeld lab, women training fasted or fed, and the changes in body composition over time, there's no influence of fat mass or lean mass whether you're training fed or fasted.

Dr. Gabrielle Lyon: 1:07:31

That's a big bomb to drop, but also really great for women who do well, are there any studies that you know of that show that fasted training is detrimental to health outcomes?

Dr. Lauren Colenso-Semple: 1:07:49

No, if anything, fasted training, in some cases, was a little bit better, but I don't think the effect is such that I'm a proponent of fasted training, my message is, do whatever you prefer. I think some people feel better training fasted. Some people feel better training with some food in them, and either of those are perfectly fine. What's most important is that you're getting sufficient total calories and protein throughout the day, not the actual timing of those nutrients, and

Dr. Gabrielle Lyon: 1:08:21

that's important. I will say, in terms of fasted training, there is some good work out of Copenhagen, and they look at low glycogen, state training, training low and it seems that there's an increase in interleukin six, and that can help with substrate utilization. Seems that there is a more robust release of interleukin six. So that's a myokine, as you know, and for the listener. But again, I think that's fascinating. I don't know if it is going to have meaningful outcomes, because these myokines are released based on intensity, duration of training. But I did think that that's interesting, that training in a low glycogen state may change the release of these myokines. Again, we're talking about something in isolation, but for you guys who like to train fasted, again, I do. I don't see a problem in it, but I will say, if you are looking for performance, it seems if performance is the outcome, for example, you're going to go run a marathon, perhaps fasted. Training might not be ideal if you are pregnant, probably also not ideal or if you're trying to get pregnant. You know, I don't know if there's any data to support that, but as you had mentioned, cortisol is, you know, considered this stress hormone, but it does play multiple roles in the body. There is challenges with cortisol being elevated over long periods of time, also called Cushings, which is a diagnosis,

Dr. Lauren Colenso-Semple: 1:09:53

but which is indicative of a underlying health problem. And so I think. When we talk about kernels of truth, then we're saying, oh, in Cushing's, for example, there are people who accumulate body fat or redistribute body fat. That's the case in somebody who has a health condition. That's not the case for these short term fluctuations in healthy individuals. So there's a lot of fear based messaging around cortisol, and people are worried that they have elevated chronic cortisol and they don't their cortisol levels are fluctuating normally, and there isn't anything to be worried about in terms of your changes in body composition, if you are a healthy individual, yeah,

Dr. Gabrielle Lyon: 1:10:40

and it's probably more important to consistently train than it would be to not. Is that, is that fair to say?

Dr. Lauren Colenso-Semple: 1:10:48

Absolutely, there's messaging out there for some people post menopause that they shouldn't be doing high intensity training because of the cortisol response, for example. And then they're saying, oh, you know, you're going to accumulate body fat because it's high intensity training, that's not a good message. Have

Dr. Gabrielle Lyon: 1:11:03

you ever seen that? No, I've never seen that either. Do you think that there is a role for thinking about cortisol levels in training,

Dr. Lauren Colenso-Semple: 1:11:18

not that's relevant or actionable for us. It's true that it increases during exercise. It's also true that your heart rate increases. It's also true that your blood pressure increases. These are these are things that the system is designed to regulate and doesn't require us to manually intervene. What about the

Dr. Gabrielle Lyon: 1:11:36

idea that cortisol breaks down muscle. It does have those properties. It is it does promote protein breakdown, but once you feed then I'm assuming that that system stops.

Dr. Lauren Colenso-Semple: 1:11:54

Yes, there's nothing to suggest that that acute level of cortisol that, again, is normal, is going to exacerbate protein breakdown to the point that it will exceed protein synthesis and then would interfere with your muscle growth. And again, we look at the human subject data, it's not interfering. There are people who are training fasted, who are gaining muscle. The

Dr. Gabrielle Lyon: 1:12:17

idea that menopausal women, menopausal women should avoid strenuous exercise. Is that true or false?

Dr. Lauren Colenso-Semple: 1:12:25

False, all physical activity is good. And I think a lot of the issues with some of this messaging is that it's just making things so complicated, and so people don't know what's good and what's bad and when to eat and when to exercise, or how to exercise, we need to be stressing efficacy, simplicity and sustainability. Let's talk about things that work and that people will continue to do long term, because that's what's beneficial for body composition, and that's what's beneficial for

Dr. Gabrielle Lyon: 1:12:59

health. What about variations in nutrition. For example, should a woman ingest protein prior to training? And again, we're talking about training as a whole. This could be, I don't care if it's endurance training, I don't care if it's strength training. We could just pick strength training or ingest dietary protein 30 to 45 minutes after in that quote, anabolic window. No

Dr. Lauren Colenso-Semple: 1:13:24

data to support either recommendation. What's important is total overall protein intake and overall calorie intake. Obviously, we don't want to be chronically under fueled. If you're somebody who has an eating disorder that is associated with higher chronic levels of cortisol, for example. But assuming you are eating a sufficient number of calories and adequate protein, the nutrient timing is not important. And again, this is something that was addressed over a decade ago, because people used to think I need my protein right after I train. There's this anabolic window. It's not true. When we measure protein synthesis, it's elevated for 24 hours plus post training. So you have a lot of flexibility in when you get that protein in. Just make sure you get it in at some point. And

Dr. Gabrielle Lyon: 1:14:14

I will say, she's saying that it's elevated for 24 hours plus. Please just try to get in the same day. I really like individuals to try to be consistent, which I think that you believe in for sure. Is there a protein target that you like or that you've seen in the literature for body composition, for maintaining lean mass and lower body fat?

Dr. Lauren Colenso-Semple: 1:14:40

There's probably a range, and some of this is in the context of using this kind of lean mass target versus body

Dr. Gabrielle Lyon: 1:14:49

weight. This is great, wonderful, yes. But

Dr. Lauren Colenso-Semple: 1:14:54

practically speaking, most people don't know their lean mass, and so they aren't. Going to be able to scale it. So, you know, I think that Stu Phillips would say a minimum of 1.2 grams per kilogram, probably up to 1.6 grams per kilogram. And if you want to eat more than that, there's no problem. It's not going to be harmful, and we should also consider the effects of dietary protein on things like satiety. But these really, really high protein targets, I don't know that we have enough data to show that they are going to be a game changer for body composition. So I think what we want to focus on is people at least hitting that minimum, and then we can kind of rethink from there. That's

Dr. Gabrielle Lyon: 1:15:48

really good advice. What about carbohydrate intake? Have you thought much about carbohydrate intake when it comes to optimizing body composition?

Dr. Lauren Colenso-Semple: 1:15:56

The data shows that you can adapt similarly, change your body composition on a higher fat or lower carb or higher carb, lower fat diet. So the way that I would approach it is make sure that you're getting your protein and then adjust based on preference. Of course, we don't want our dietary fat to get super, super low. But I think for why is that that can have some effects on your hormone levels, and we want to make sure that we're getting sufficient nutrients overall, in general. So I think whenever we start to really restrict one macronutrient, we can run into some issues with micronutrient deficiencies, or potentially overall caloric intake. But a lot of this should be based on preference. Some people just prefer higher fat foods, and others prefer higher carbohydrate foods, and both are fine. Yes,

Dr. Gabrielle Lyon: 1:16:53

we would also agree with that focus on dietary protein first 1.2 to 1.6 grams per kg. I don't care if people go above, I certainly don't want them to go below. The rest of the calories can be carbohydrates or fat, depending on what you prefer, but if you are going to eat a higher carbohydrate diet, you probably do need to be doing some form of activity. Otherwise, you know, becomes difficult to utilize those carbs in a meaningful way. And

Dr. Lauren Colenso-Semple: 1:17:22

if you're somebody who's doing a ton of high intensity or endurance training, then you might want to push those those carbohydrates higher. But I think for most people who are just looking at being healthy and maintaining or changing body composition, that yeah, I would agree with you.

Dr. Gabrielle Lyon: 1:17:34

What about intersect rest periods in resistance training? So are there sex based physiological differences that justify shorter rest intervals between sets for women in strength or hypertrophy programs,

Dr. Lauren Colenso-Semple: 1:17:47

I am really surprised to see this message floating around, because just for the listener, when we think about interset rest, this is you're doing your set of 10 squats, for example, and then You're resting, and then you're doing your second set of 10 squats. And so the message that was put out there is women will gain more strength and muscle if they use shorter rest periods. So if you only rest for a minute in between those sets, instead of resting for two minutes or three minutes, whereas men should be using longer rest periods, and there's data in men and women that if you're really cutting down the rest periods, you're going to compromise the total amount of volume you are performing. So let's say I did 10 repetitions on my first set. I didn't get enough rest on my second set, maybe I'm only going to hit six. And so overall, that is not optimal for increasing muscle size or for improving strength, because we want to make sure that we're getting adequate rest in order to try to repeat that performance. So again, data in men and women show if you want to optimize your strength and your hypertrophy, you should be making sure you get adequate rest, definitely not trying to intentionally shorten those rest periods.

Dr. Gabrielle Lyon: 1:19:13

That's fascinating. That is really interesting. What would your big takeaways be from all of your work. What advice would you give both women and men out there as they are thinking about training for hypertrophy, overall health?

Dr. Lauren Colenso-Semple: 1:19:35

Keep it simple. The basics that we've talked about here today are what's important. So if you are doing a challenging resistance exercise program that you enjoy, that is progressive in nature over time, and you're eating sufficient protein, you will put on some muscle size, you will gain strength, and that will be in. Credibly Important for your health and your physical function as you age.

Dr. Gabrielle Lyon: 1:20:04

Menopause. Menopause, well, you know it's going to happen to 50% of us. It's coming just like Christmas, Tax Day and New Year's. There seems to be some individuals that really struggle with body composition changes, versus some that they just, oh, I guess I just went through menopause. What do we know about the body composition changes in menopause?

Dr. Lauren Colenso-Semple: 1:20:30

You're right. There's a huge variation in individual response, and a lot of it isn't very easy to predict. Even when it comes to symptoms that people will get during the transition. Some people get terrible symptoms. Some people barely get any at all. I think we know that obesity and smoking are associated with higher likelihood for these symptoms, but in terms of the changes in body composition, we talked about muscle before muscle loss occurs with aging in both men and women. It's not clear from the data that there's anything unique about the menopause transition that is accelerating muscle loss, because we see negligible loss during that four year transition. Let's say when we think about body fat accumulation. That's kind of a different story, because what we see in the menopause transition is a redistribution of body fat, and so you're getting more adipose tissue in the abdomen area, more visceral fat, potentially. And the good news is we have data to support these changes due to exercise and diet. So it's not that there's something unique about this body fat post menopause that is resistant to diet and exercise. However, we don't really understand why some people experience that body fat redistribution? Do

Dr. Gabrielle Lyon: 1:22:03

you think that there are and there's things that we don't totally understand, which, with the increase in FSH, follicle stimulating hormone, do we know if that impacts metabolism in a meaningful way?

Dr. Lauren Colenso-Semple: 1:22:18

It's doesn't seem that your resting metabolic rate is changing just due to your menopause transition, but one of the most powerful things you can do is be physically active and make sure that you're dialed in on the level of physical activity as you go through that transition, because with aging in general, people tend to start to be less physically active, and there are sometimes changes in diet that are not intentional, but they're happening. And so we see it in men as well. With age, increase in body fat and a loss of muscle mass.

Dr. Gabrielle Lyon: 1:23:02

Dr Lauren Colenso Semple, thank you so much for coming on. I have to say this is one of the most requested topics, is hormones and training and life transitions. You cleared up a lot of facts and a lot of myths that I think will leave people much more at ease to be able to attack the day and really get after their training and not necessarily worry about if they're fed or if they're fasted, or if they're menstruating or not menstruating, but the most important aspect is they get it done. Yes. And again, thank you so much for your contribution to the scientific literature. Thank you very valuable. Thank you so much. Thanks for having me. If there's one thing you take away from today, it's this, your physiology as a woman is not a limitation. The science is clear. You can train consistently, lift heavy and build muscle year round. If this episode challenged what you thought you knew, share it with another woman who needs to hear the truth you.