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Welcome. Hi, I'm Mikki and this is Mikkipedia where I sit down and chat to doctors, professors, athletes, practitioners and experts in their fields related to health, nutrition, fitness and wellbeing and I'm delighted that you're here.

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Hey everyone, Mikki here, you're listening to Mikkipedia, and this week I speak to Lauren Calenso Semple, who is a coach and PhD researcher who is currently pursuing her PhD at McMaster University in Canada under the guidance of Stu Phillips on training for the menstrual cycle. In this episode, Lauren shares her insights on the topic of menstrual cycle training based

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currently undertaking and talks about this from both a coach and a researcher perspective. We discuss the limitations of current techniques used in the literature to determine menstrual cycle stage and how her research will contribute to a more robust evidence base that will determine whether the added complexity of menstrual phase training is evidence based and necessary

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and performance. Overall, I have to say this evidence is a must listen for anyone interested in understanding the evidence-based approach to menstrual cycle training. Lauren and I also talked briefly about the evidence for nutrition-based changes as determined by menstrual cycle phase. So I really think you're going to get a lot from this

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her PhD in Integrative Physiology at McMaster University. Her research focuses on the impact of exercise, nutrition and hormones on skeletal muscle. She has also worked and continues to work with hundreds of clients in person and online, including recreational lifters, mums-to-be and aspiring power lifters and physique athletes. Lauren is also a contributor to Mass, which is

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Stronger by Science. Those people interested in Physique Science will be very familiar with these. I subscribe to Mass. It is such an excellent publication. And her most recent paper has actually just been published in the frontiers of sport and active living. And we have a link to this paper in the show notes today as well. Before we crack on into the interview though, I would just like to remind you that the best

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subscribe button on your favourite podcast listening platform. This increases the visibility of the podcast out there in amongst the literally thousands of other podcasts, so more people get the opportunity to learn from guests that I have on this show. Alright team, please enjoy the conversation that I have with Lauren Calenso Semple.

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Lauren, thank you so much for taking the time to speak to me today about the evidence base for menstrual cycle phase training. And I understand that in your, both in your research and of course your sort of background as a coach, this is something which you have a lot of experience and then something that I get a lot of questions on as well in relation to when I speak to clients about well both diet and exercise.

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by giving the listeners some information on your background? Sure. I have a bachelor's degree in psychology and nutrition from the University of Buffalo, after which I worked for a few years. That's when I started coaching clients and ultimately volunteered in a lab for a bit and got really into research and decided to go back for my master's. I earned my master's degree from

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with Bill Campbell and then I came to McMaster University in Canada to start my PhD with Stu Phillips and I've been here for almost four years now so I'm just at the tail end here of my degree. Amazing, so you're in write-up phase? Doing a bit of analysis still, just there's so much tissue. I had my study

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a little too processed. For sure. And gosh, you also did your masters with Bill Campbell and you're doing your PhD with Stu Phillips. Do you like with the gurus in this space, Lauren, how exciting for you? Yeah, I've been really fortunate to work with some incredible mentors. The first lab I worked in as a volunteer actually was Brad Schoenfeld's lab, who you may have heard of.

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the two academic years, I spent the summer in Fullerton in Dr. Andy Galpin's lab, which is also a really wonderful experience. So I've worked in a lot of different labs and with some really, really great people. That is awesome. And so, and obviously your work as a coach, you work with a number of clients. I imagine many of them sort of female. How did you, I mean, being female as yourself, obviously, but how did you get interested in sort of wanting

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about menstrual phase sort of based training? I think it started with just noticing the lack of research in women in the exercise science space. Because of course, when I was first getting interested in the research, I was really interested in improving my own athletic performance and in making sure that I was coaching my clients in an evidence-based way.

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majority of the evidence that we were pulling from as coaches were done in young men. And so I think going into my masters, it was more about just wanting to do more resistance training research in women. And then after, and unfortunately, I would say there has been an

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where we're starting to kind of close that gap. But of course, when you look at female specific resistance training guidelines, just in kind of the general public on blogs and in social media, you really do see that the menstrual cycle is something that you should really be aware of, or are oral contraceptives better or worse for strength and hypertrophy? And there's a lot of kind of mixed information

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I think, out there. And also one of the reasons why women are often excluded from these studies is because there is a concern that the menstrual cycle phase in which you're tested or the schedule around the resistance training is something that will be a confounding variable. And so you need to quote unquote control for the menstrual cycle.

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And given the inconvenience and difficulty associated with that, it's just easier to do your study in young men, right? And so of course that then begs the question does it really matter or and if it and if not then why not Include both sexes in studies And so that that when I started taking a deeper dive into the literature I realized you know, I think it's really premature

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to say, yeah, this really matters and we need to be programming around the menstrual cycle or excluding women from research because it's going to be this huge influence. Yeah, interesting. What was your master's topic on? I mean, I know what was on, but what were you looking at? I actually looked at different training volumes in women and so I had one group exercising three days, sorry, both groups exercised three days per week.

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but one group did two sets of six exercises and the other group did five sets of all the six exercises. And so it was a pretty substantial volume difference. And we looked at strength outcomes and also muscle thickness changes in the lower body. And the results were quite similar between groups despite the fact that the high volume

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spending over twice as much time in the gym. Oh, that is good news because I follow a program that has like about 18 exercises in it for like the same body part. And I end up doing like about a third of it and go, this is me, I am done. So it's quite good that I'm saving myself time, not needing to be in the gym. So Lauren, can we, with regards to menstrual cycle training, it is really interesting.

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interesting that up until this point, or not this point, but a number of years, a couple of years ago, it either wasn't considered when we're looking at the basis of research. I remember looking at studies and it was not mentioned or almost ignored or not even really talked about, or women weren't involved.

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If it was such a concern and it did make such a difference, would we then have to like throw out all of the research that's gone before? I'm not sure I'd say throw out, right? I think one of the most important things to remember with the results of all these studies is that you're looking at group level averages. And so we're saying, you know, on average, this particular sample, you know, did a good

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did a bit better with this protocol than another, if you're looking at kind of between group differences. And then, and so to say that the menstrual cycle phase would be such an influence that it would really disrupt those group averages, I mean, it would have to be a really substantial influence. So I think that we're definitely

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not in a place where we would say, oh, scrap all of that because they didn't account for the menstrual cycle. That said, it is a criticism. So if you try to submit a paper for peer review to a journal and you did not account for or track the cycle and try to standardize the testing phases in some way, then you will be criticized for that. And you need to perhaps explain that

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a shortcoming of your work, at least at this point. Okay. Interesting. And before we get to what we do or don't know about how the menstrual cycle may or may not impact on performance outcomes, can we just start with the basics and walk through some of the changes that occur across the menstrual cycle, which may actually result in, or there

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a mechanism for a sort of a difference in outcomes? Sure. So during the first half of the menstrual cycle or what we call the follicular phase, it starts with the onset of menstruation. And so for those first several days, both of the primary hormones in question here, estrogen and progesterone are very low.

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phase, progesterone stays low, but estradiol starts to increase. And mid-cycle, right before ovulation, is when we will see peak estrogen levels throughout the cycle. After ovulation, the estradiol levels are kind of moderate to high, but not as high as they were in that peak. And then the progesterone levels start to increase slowly so that they're moderately

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throughout the luteal phase or the second half of the cycle. And then both hormones decrease and we start a new cycle. Right. So what happens, what is it about the change in hormones that may influence sort of performance outcomes or how someone might feel when they're training? And we're thinking predominantly about strength training here, aren't we?

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Hormone has been studied in animal models looking at the influence of estrogen on muscle in rodents and the major model that that they'll use for this kind of research is called an overactomy when you Remove the ovaries. So basically you're you're having very very low levels of the hormones and so this would be much much lower than

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what a menstruating woman or even a post-menopausal woman would experience. But the model shows us what happens in the absence of the hormones. And you do see these detrimental effects to muscle. And so those results indicate that perhaps estrogen is involved with repair for muscle damage.

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it's involved in muscle growth or perhaps the absence of estrogen is associated with muscle loss and strength loss. And there are a few different mechanisms that have been proposed here. It could be an influence on muscle protein turnover. It could be an influence on myosin function. It could be an influence on satellite cells.

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The extent to which this translates to humans is really yet to be determined because, again, I want to stress we're talking about a model where there really is the absence of the hormone. And so you're looking at an extreme example, whereas throughout the menstrual cycle, we're seeing fluctuations in hormones. But it isn't like an on-off switch.

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Okay, okay. And with regards to any human data, like, so is there, so what does the studies, what would the study show there if there is, if there are studies, which sort of look at this? There are a couple of studies that show that training in the follicular phase, when we

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gains compared to training in the luteal phase. And so the the proposed sort of reasoning behind that is that either there's something anabolic or stimulatory for growth about estrogen, or there's something catabolic or inhibitory about progesterone. And I mentioned what we what we know from the

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about estrogen that, you know, perhaps the absence of it is problematic, but we know very little about progesterone and there really haven't been any studies to indicate that in fact it is catabolic or potentially problematic for growth.

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the findings of those two papers. And just that, well, if estrogen is a positive, then progesterone must be a negative. Yeah, it's interesting because I've heard people describe progesterone as extremely catabolic even. And they're like, oh, in your luteal phase, it's extremely catabolic with the progesterone.

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protein intake quite a lot. I mean, I'm a massive advocate of protein anyway. So I, you know, like, it's, as you know, you study under Stu Phillips, I think he's a bit of a, you know, he is like the protein guy. But the extent to which progesterone is catabolic. So has that only come about because we haven't seen the same gains in the luteal phase? Or what mechanism might be behind that?

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massive assumption and I don't know because it really it hasn't been studied and it needs to be at a purely mechanistic level. It hasn't been looked at. We know that there are progesterone receptors in skeletal muscle and that's sort of it. So I and I've seen those recommendations

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is sort of shocking to me because in order for that to be necessary it would have to be massively catabolic. Yes, it'd be wasting away through half of the month. And if that's the case then why is it that women on a relative basis

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I mean, it wouldn't make sense if half of the month, you're basically, you shouldn't even bother resistance training because you're in this extremely catabolic state. Yeah. Yeah. Super interesting. And I think I've seen someone talk about there's an increased protein turnover or something during the luteal phase. But even I might even have just been imagining that actually, like someone might have just been speculating as to why.

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Mas, I mean, obviously you've just told us there's no mechanistic data to suggest that it could even be sort of a possibility, much less, you know, human clinical trials showing it. So super interesting. It's definitely one of the areas of the literature that is, it's a huge gap. And I look forward to learning more about progesterone. But we're certainly nowhere near the point where we should be making practical recommendations

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exercise programming or nutrition based on this guess. Yeah, yeah, no, I totally understand. Now with regards to the follicular phase and the ability to build more muscle during the follicular phase, I've heard you describe it before in that, estrogen is only high for a certain number of small amount of time

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phase, isn't it? It's not like it's extremely high during follicular because of course with the menstrual cycle both hormones are low. So can you explain that a little bit further Lauren? Yeah, I would encourage your listeners to perhaps Google hormone fluctuations throughout the menstrual cycle so you can get a nice visual here. But what you'll see is, let's say the first seven

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a fairly heavy spike in estrogen that takes place over maybe three to five days. And then we have ovulation. And this varies between individuals. And the extent to which we're getting a big increase in estrogen is also going to vary between individuals.

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the latter portion where estrogen is high, and then you compare that to the luteal phase where both hormones are kind of at a moderate level. But when it comes to estrogen, it sort of seems like a wash because you have low and then really high in the one phase and then you have moderate in the other phase. And if you kind of collapse it, then over the cycle, you're at a kind of moderate level.

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And so in order for there to be something very special and anabolic about estrogen, not only would that have to be the case, but it would have to be very potent and stimulatory just for several days. And that's a bit hard to reconcile because, like I said,

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situation, but is three to four days of high estrogen so additive to growth and gains in muscle strength that it kind of blows training in the luteal phase out of the water? Probably not. Yeah. And of course, throughout the follicular phase, we do get a bump in testosterone, don't we?

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up to ovulation, how much would that contribute to muscle growth or that feeling of, because people often relate your whole menstrual cycle to the ways that you should feel. You should feel bulletproof and you should feel like you could win a strong women competition. And then you should feel like you want to go away and hide in a hole for 10 days or whatever.

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know? Oh, I mean, what we know about about testosterone has changed considerably over the past 10, 20 years or so, because it used to be thought that that testosterone was this huge driver of, of hypertrophy. And while that is probably true during, during growth, so you know, during adolescence and the onset of puberty, um, when you are an adult, and

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you have testosterone levels that are in a normal range, that is not associated with your hypertrophic potential. Testosterone levels in men can vary considerably into, you know, there's quite a large range of what's normal, but as long as you are within that range, there is really no kind of predictive element

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of your potential for hypertrophy. And that is kind of in contrast to what we thought 20 years ago, 15 years ago. And similarly, there used to be a lot of attention around these kind of post exercise spikes in hormones. And that was this anabolic window and you're really looking to, there were even training programs

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like your biggest increase in testosterone and IGF-1 post-workout. And now we see that, yes, well, you do see an increase. What's important is what's going on, bigger picture, day to day, and the same thing with protein turnover, right? And so what we see with these small windows

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increased hormone levels are not translating into something meaningful for response to exercise in terms of muscle growth. So that's another reason why we have to be a little bit skeptical about the actions of the female sex hormones, right? Because if, not to say that they don't play a role, but what we see with the

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testosterone, for example, is that it's only massively anabolic if it's taken at supraphysiological level. So we're talking about people who are taking exogenous hormones. And the fluctuations in men throughout the day, for example, are not something that we really need to pay close attention to.

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in naturally cycling women is that we do see these variations throughout the month. The week to week, the hormonal profile is a little bit different. Yeah. Okay. You mentioned naturally cycling women, and obviously a lot of women are on hormone contraception, be it a localized IUD or be it the oral contraceptive pill.

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of that on muscle? If you know, is it detrimental to muscle gain or performance? Does it not make a difference? So, and first, can you also describe just for people who are unaware, what happens when you take an oral contraceptive to your cycle? Sure. So when you're taking the oral contraceptives, those are exogenous hormones or synthetic hormones. And the most common

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version of that is a combination pill. So you're having, it's a synthetic estradiol and a synthetic progesterone or a progestin. And those pills shut down your endogenous or kind of natural hormone levels. And so you no longer experience the hormonal fluctuations that I described earlier during the menstrual cycle, because you're not actually experiencing

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regular menstrual cycle and more. And there have been several papers on this topic and the research is really mixed. Some say some show you know a small effect that it's beneficial, others show a small effect that it's detrimental, but I think the biggest takeaway that we have at this point is to say in either

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So I would decide to go on oral contraceptives or not based on a whole other host of factors and my potential response to resistance training would probably be very low on the list. Yeah, yeah. Okay, no, that makes perfect sense. And it's interesting, not a lot of people, and I think probably women are now aware of

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of this, but if I'm talking to teenagers about the menstrual cycle and I say to them, it actually shuts off your cycle rather than regulates it, it's quite a surprise to them and actually a surprise maybe to their parents as well. So maybe I was too quick to say that I think women know this because actually I don't think a lot of women realize that that's actually what happens because when you go on an oral contraceptive for reasons other than contraception,

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shut it down. I'm not sure if it's the same in America or Canada, but that's what we're talking about. Yeah, it's a really good point. My experience in Canada isn't as... I've only been here for a few years, but in the US, it was very, very common for physicians to suggest that you go on oral contraceptives to, as you say, regulate your cycle. But the only regulatory

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where you no longer take the hormones and then that allows you to have a breakthrough bleed that's not actually a real period. So I guess it psychologically regulates your cycle. But if there's a hormonal imbalance, that's not fixing it. No, it's just sort of masking it until such time that you may come off and then everything, all the chickens come home to roost. I think that's

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Lauren, what about menopause and perimenopause? Because obviously, particularly perimenopause, there's significant fluctuations in estrogen, progesterone is on its way out, testosterone levels drop a bit. And more and more, of course, if you look out on social media, not only are there recommendations for how to train around your cycle and eat around your cycle, there are now recommendations

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menopause, menopause. So do you have any comments or experience in that realm with regards to what you're looking at? I do think this is a very important area of research and I will tie this back to the animal work I discussed earlier when we're seeing that there might be something to it with the

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this is why we see muscle loss, strength loss, loss of function in older women. I think that might be a component to it and it's definitely something that we should keep in mind. I know that there's kind of mixed reviews on the potential influence of hormone replacement therapy, but that is something that is interesting to me.

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biggest thing I would say we can do in order to set ourselves up for that perimenopause period is to start resistance training as early as we can. And so, yes, if you start training at 50, 60, 70, you do still see benefits, particularly with kind of functional assessments.

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I think we would set ourselves up for more success if we kind of put on the muscle preemptively. And then, yeah, maybe we still are going to experience some muscle loss, some loss in strength, but you've built your savings account early on, so you have a cushion there for some of those losses.

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It is more common for women to lift weights, but that certainly hasn't always been the case. And I think our current generation of women in that age group, it's not the norm that they lifted weights throughout their adulthood. Yeah, it's interesting. I was reflecting on this this morning for whatever reason. I think I saw a post saying, you're doing it all wrong or something like that. The message was that if you're doing all cardio, then you're doing it all wrong.

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Which is true. However, of course, 20, 30 years ago, this is what the research sort of told us we needed to do. It's just a change in what we know. And when the messages are sort of put out there like that, it's not necessarily blaming the woman for it, but that's sort of the sense of it. Like, oh, if you're not seeing results, then it's obviously you're doing something wrong. But based on, you know, but everything evolves and it just takes a little bit more time for sort of people to catch up.

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I suppose when it comes to the menstrual cycle in the sort of phase-based training, this is yet another thing that woman could potentially go, oh, well, no wonder I'm not seeing results because I've been doing X, Y, Z in the gym on this day of the month when really I should have been doing yoga or something like that. Yeah, I'm disheartened to see information like that because I think that exercise is good in any form.

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So to kind of make people feel like they're inadequate or they're doing something wrong or they should be doing something differently. I mean, can you improve your exercise habits and your program? Absolutely. But you certainly shouldn't be shamed for having what is theoretically suboptimal habits

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so overwhelmingly positive, even at small doses, that I think we should really be looking at the big picture here of what's important and how can we maximize the benefits instead of really over-complicating things and saying, oh, what a waste of time if you're exercising and you're not wearing that wearable

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sleep or writing down everything you eat or training around your menstrual cycle. I think there's so many messages about how all these things that we need to be accounting for and concerned about and that can make even just the prospect of starting an exercise program incredibly overwhelming. Yeah, yeah for sure. And then of course, you know, you're a researcher but you're a coach as well. What's your practical experience of training women?

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Like how much does the menstrual cycle play into how they, psychologically how they feel on a month by month basis, but also with any progression or anything like that. So Lauren, what's your sort of world, real world view? Yeah, I think that in, with many of my female clients, they tend not to push themselves as much as they can.

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little bit of a self-confidence thing there. And once I encourage them to really focus on progression and can we do another repetition on that exercise this week? Can we add a bit more weight? Then you really see some amazing progress. And I think that's also really beneficial psychologically as well, because you see, I'm tangibly getting stronger here.

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is changing and that can really help with adherence because you see yourself really reaping the benefits from week to week or month to month. In terms of the need to account for the menstrual cycle, I will if it's something that comes up for that individual client.

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And some people, I just work on their exercise program. Some people I also work with on their nutrition. And there are some people who have issues with digestion and we need to really kind of work out some GI issues because those are interfering with their training or with their diet.

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you know, issues with travel and we need to adjust their programming, you know, accordingly. And of course, if you have an illness that comes up, then we need to adjust. So I really kind of put the menstrual cycle in that, yeah, let's address it as needed kind of category. And if we know,

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symptoms kind of regularly around this time of the month, then we build in some sort of rep ranges that we should hit, or maybe we adjust kind of an RPE or an RIR goal. And then that allows you to go in and feel like, oh, I can still have a good workout, but maybe today is not the

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more weight or maybe today's not the day to do a strength assessment because I don't feel great. But I would apply the same rules if you didn't feel great for another reason. I think it's just a personal call. And maybe if you didn't get enough sleep the night before, then that would also be a day that maybe you're not going to set any PRs. But I have never

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seen any kind of across the board trends in terms of menstrual cycle with my clients. Other than the fact that around the onset of menstruation, the majority of people tend to gain a little bit of scale weight. That's the only trend I've ever seen. And so for that reason, if we're on a kind of weight loss plan, then I would discount those numbers from my average. Yeah, yeah. Okay.

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Really what you're talking about is individual and how someone should approach what they do on a month by month basis is based around how they experience their lifestyle plus menstrual cycle, not necessarily that there's a strict protocol that you should adhere to.

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it comes to all aspects that are going to affect how you perform and how you feel. And if you start to see some trends, then you can make an adjustment. Another example that comes to mind is people who exercise early in the morning. Some people love that and some people feel terrible. And if you try it out and it really isn't for you, then see if you can exercise in the evening instead.

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And, and, and, but that's totally individual. I wouldn't say, oh, clearly, you know, morning workouts are bad for everybody, but they might not be a good fit for you. And so it is, it really, and that's the art of coaching, right? We have fundamental principles that, that we, you know, that we can start from and we'd like to be evidence-based in our practice.

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And the results of all these studies, which as we discussed are group averages, are not necessarily going to apply to that one individual. So the science is a starting point. And then the adjustments that we can make in a coach-client relationship, that is where the individualization really comes into play. Yeah, no, that's great. And then of course, if someone is tracking their cycle, they're able to get a sense of what happens month on month. But as I understand it, and I think you spoke about it,

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about this on the Iron Culture podcast, not only are there differences between women, there are differences for a woman, depending on any given month as well. Is that right? Absolutely. I mentioned earlier that there are these couple of papers that show that follicular phase-based training was superior to luteal phase-based training. One of the

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It comes back to the methods of how they determined cycle phase. And so when you look at an average menstrual cycle, it looks at approximately 28 days and ovulation occurs on day 14. And you can detect ovulation in a few different ways.

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tell you when you're ovulating, that's an estimation based on your cycle length on average. So for most people, if they have a longer cycle, they will ovulate a bit later in the month. So that to say, there are plenty of women who have 25-day cycles and some who have 35-day cycles. And there are women who ovulate on day 12 and women who ovulate on day 19.

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Sometimes there is no relationship between ovulation timing and cycle length. And so in my research, I have them track their cycles for several months before even participating. And during that time, my participants take urinary ovulation tests. And so we can determine the timing of their ovulation.

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from month to month, as you alluded to as well. So there's a ton of variability there. And the reality is that unless you're tracking for fertility purposes, the majority of women are not regularly tracking their ovulation. So in that sense, you don't actually know that you're in your follicular phase or your luteal phase. So this attempt to structure your diet and your exercise around that,

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actually even be doing what you're intending to do, because you don't have the information to really plan it that way. Yeah, for sure. And you mentioned that temperature isn't the best indicator. And this is one which I see recommended all of the time, is you just track your temperature and that'll tell you. And I've said that to several people as well, because that was, in my, as I understood, that was your, the best sort of proxy. But what are the challenges there, Lauren? Yeah.

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Basal body temperature is something that has been used in the literature as well, and I know has also been recommended in the past for fertility purposes. But if you look in the gynecological community, that's no longer recommended. And it, and you're really, it's not a good method on, for research,

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individual woman. You're looking for a very small increase in basal body temperature that is... It's indicative that ovulation has occurred because the increase in progesterone in the luteal phase can cause a small increase in body temperature. But importantly, there are

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that influence basal body temperature, including stress, alcohol, illness, your environment. So it's difficult to even get a consistent read. And then we're talking about a very small increase that some women don't even experience. So they ovulated, but they don't experience an increase in basal body temperature.

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The convenient one is the urine strip, so they are detecting the surge in luteinizing hormone that's associated with ovulation. And the other way would be a blood test. And again, we can measure luteinizing hormone in the blood as well. Okay. And how accurate is luteinizing hormone? Is it like if there's a surge, is it a surge that might last for several days so you know that it's definitive?

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Yeah, that's a really good question. And what you'll see is the degree to which we get a surge can vary between people and the length of time for which the surge hangs around also varies. And so you might see positive tests for two or three days, or you might miss it,

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because it occurred over a period of hours, in which case I would say, oh, can you go back and instead, for purposes of research, I'd say, can you take multiple tests in this day, just in case we have what's referred to as a fleeting ovulation and it's a really kind of finite window. So it's not one size fits all by any means. No. No. And are there any patterns, Lauren, with regards to the type of woman who might get a fleeting

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of ovulation versus someone who has experiences more drawn out. Do we know anything about that or is it actually just quite individual? No. It's very individual and it can also change from one month to the next. You can also experience an anovulatory cycle and maybe you don't ovulate that one cycle.

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it's there there are some women who are very very consistent with their cycle length and their ovulation timing but there are also women who are not and I think it really I don't have a good explanation as to why that might be. Yeah okay no that's that's totally fine and I mean so really where

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To me, the state of the evidence right now is that it's how you could train in and around your menstrual cycle is actually, it's much more, it's more about how you're feeling on a day-to-day basis, and less about the menstrual cycle, and more about overall sort of just state of being really. I mean, I would say so.

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pattern of feeling of particular way, then maybe you try to incorporate a kind of auto-regulatory approach to your training. And it's not that it isn't. If you're taking your training really seriously and you really want to account for all of these things and you do start to notice some patterns here, then I'm not saying, I'm not

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that perhaps there would be some differences in motivation to train or menstrual symptoms or other factors that would influence your performance. But I think that this idea that we all need to kind of adjust our training based on cycle phase,

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to suggest that, I don't know that it would ever be appropriate to suggest that because it also kind of assumes that everybody has the same goals and that everybody is willing to perform this type of exercise or that. And I don't know what you've seen, but I've seen some like, oh, you should be doing light stretching or yoga that week. You know, what if I don't like yoga? What if I'm not going to do yoga? Should I just not exercise? Yeah. And I sort of feel like if, you know, if you are more

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in one particular phase, then that would almost suggest to me that you need to go harder in your workout. So you get the benefit from one aspect of it rather than, and you take your recovery seriously and have a lot of protein, but not necessarily that you need to like shut up shop for a week or so and then sort of come back into it. I've also seen some recommendations for

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cycle phase and that is pretty mind-boggling to me because you know when you're when you're talking about exercise performance it's intensity dependent right so depending on the on what the activity is yes we will be burning more carbohydrate or more fats and so the idea that regardless of what you're doing you should be adjusting your nutrition simply because the

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the menstrual cycle would have that influence, it doesn't make sense. If you're going to do some power lifting and I'm gonna run a marathon, our dietary needs are going to be very different for performance and our fuel utilization will be very different. So I'm really perplexed by those sorts of blanket recommendations in terms of adjusting

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Yeah, yeah, no, I totally appreciate what you're saying. Finally, Lauren, can you just tell us a little bit about your research and sort of where it's headed and what it's going to help inform for us? Sure. So one of the biggest things that I tried to implement in my studies is what we're trying to call gold standard menstrual cycle verification methods.

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But in some previous papers, they've just assumed that, oh, everyone has a 28-day cycle, everyone ovulates on day 14, so those people are in their luteal phase and those people are in their follicular phase. And for all of the reasons I explained, you know, that is not good enough. And if we're not going to be very, very comprehensive in the methods we use, then we can't make

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incredibly influential. So that's definitely one of the priorities with my work and also what I hope future researchers will try to apply in their own studies. But what I am looking at is the

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Pre ovulation or follicular phase they come in five days before I'm predicting ovulation and and there's There's two exercise sessions over that five day period And then we're taking a biopsy In the first day and then they exercise just one leg so I can compare the the exercising leg to the resting leg and so what this will give us is a

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synthesis over a couple of days. So in response to the two exercise sessions and they're spaced two days apart. And then they repeat that five days after their positive ovulation test. So that'll put us kind of right in the mid luteal phase. So I chose those two time points because I really wanted to take advantage of that time when estrogen is highest. So those five days and then that the

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the five days in the middle of the luteal phase. And I have them come in randomized order in terms of which phase comes first and which one leg exercises in one phase and the other leg exercises in the other phase. And so the advantage of this kind of design is that it's within subject. And so I'm going to see

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to which we get an increase in muscle protein synthesis in response to exercise in the same person in each phase. And so I mentioned there's so many differences between individuals that it's not quite as thorough a design to compare kind of two groups because we're looking for the differences

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in these hormonal profiles that are really variable between people. So that's the goal here with the menstrual cycle. And then I repeated the same study in women on oral contraceptives. And instead of doing it follicular and luteal, I did it in the active pill phase. And then during the week that they're off the hormones. Yeah, nice. And so it'll be like a case series of what you find

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research, was that like, is that how it would work? So it is an intervention. It's just an intervention. No bit. Um, I, I'm just, I'm comparing a person to themselves, a person to themselves, that's right. As opposed to one person to another. Um, and so, so, you know, the, the intervention is in your luteal phase, your left leg is exercising.

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And then in the follicular phase, your right leg is exercising. Let's see the protein synthetic response to that. And so if there is a difference, we will see it because it's in the same person. And of course, this isn't equivalent to a long-term training study where we're going to see muscle growth, but the muscle protein synthetic response is a really good indicator of kind of what's going on

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And our ability to take biopsies is really unique in that we can actually, we can really see what's going on at a molecular level. No, that's great. And I imagine that your research will be able to contribute to some of the lacking progesterone research that the fact that there's next to nothing on that space, like that'll be really great to see what your results show. Yeah.

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forward to just getting more work out there. And the ultimate goal here, whether it matters or not, is really important moving forward with research. Because if it's not important, then there's no reason why we shouldn't include both men and women, or include both women who are naturally cycling and on oral contraceptives in the same study intervention group.

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And so I think that really importantly, if it makes a difference, then it will establish kind of best practices for the researchers to account for that in their research moving forward. And if it doesn't make a difference, then it will kind of remove this level of uncertainty and this sort of reluctance to include women for the, you know, to avoid the headache of dealing with all of that.

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on. And then we can just be more inclusive in our studies and be confident that it's not a confounding variable. It's not important to make sure that everyone is tested on the same day. Yeah. No, that's great, Lauren. And is it too early to ask for any early insights from your research? Or are you currently, you mentioned at the start of our call that you're currently in the depths of measuring tissue.

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Yeah. Yeah. So we're currently doing the analysis and it's fairly time consuming. There's a lot of bloods to go through and urine, saliva, muscle. So there's a lot to sift through. But I'd say my biggest takeaways have been just that variability in cycle length and

01:00:23
how much it, how important it really is to account for this. And certainly if you are adjusting your training around this, then I would hope you were actually monitoring when your ovulation occurs. And because other, you know, if you're going to go to all that trouble, you might as well have the information.

01:00:53
That's funny actually, because you really haven't settled anything other than that it is quite individual and we don't really know a lot. But it was super interesting for us to hear that, I think, particularly because there is that strong message out there that it is something that we need to consider. Now, I understand that you are now contributing to Mass, is that correct? That is, yeah.

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and like within that publication? Yeah, absolutely. You know, I'm very excited to join the MASS team. They're an amazing group. And I look forward to covering the research that relates to what we've discussed today and some other topics as well. You know, I think it's a really valuable resource and I am very honored to join the team. That is awesome.

01:01:53
definitely put links to that in the show notes. Where else can people find you Lauren? Sure. My Instagram is laurencs1 and I hope to be sharing more information on there kind of moving forward as I come out from the cave that is getting the PhD. And I will say, you know, yeah.

01:02:23
To go on definitively right? That's just the nature of science and if you see people claiming that you know, you must be doing this or you must be doing that and And they you know, they have all the answers I guarantee you that they don't or that they are ignoring the the fact that this is really complicated and it would it would be much easier if I could come and give you like a

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really nice little answer, you know, wrapped up in a bow that clearly we need to be doing this, this, and this. And those are your take-homes. But the nature of science is that it's a process and the methods need to improve over time and we need to replicate studies in order to be confident in the results. And it's a shame that some people, you know, for

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financial gain are willing to push that aside or divert people's attention from the, you know, sometimes boring reality that maybe we just don't know yet. No, I completely appreciate that. Lauren, thank you. This has been a great discussion. I know that I'll have lots of people who will be super interested in that and will be super interested

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as well. So thank you so much for your time. Thank you so much for having me.

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