How Training, Fueling, And Stress Shape Fertility

Trying to conceive while training hard can feel like you’re being asked to choose between your identity and your goals. We go straight at the myth that vigorous exercise is the enemy of fertility and show where the real culprit often hides: low energy availability that disrupts hormones and stalls ovulation. Through clear explanations and practical examples, we map the J-shaped curve between activity and conception, highlight the gaps in vigorous-intensity research, and explain why fueling—not fewer workouts—frequently makes the difference.

We start with cycle literacy: how to confirm you’re actually ovulating, why 28 days is only an average, and what to do when your calendar method isn’t enough. From there, we dig into medical causes of irregular cycles like PCOS, endometriosis, and fibroids, and we broaden the lens to include male fertility—reminding you that 30 to 50 percent of fertility challenges involve male factors, with sperm quality changing over about 12 weeks. On the lifestyle side, we connect exercise, sleep, stress regulation, and the Mediterranean diet to insulin sensitivity and lower inflammation, setting a stronger foundation for conception.

The heart of the conversation focuses on REDs and underfueling in high-volume training. We unpack how low energy availability blunts estrogen, prevents the LH surge, and leads to anovulatory cycles, then share why a nutrition-first strategy should precede cutting workouts. The Refuel study offers encouraging evidence: maintaining training while increasing intake helped restore cycles, with realistic expectations around a modest weight gain and a recovery timeline that lengthens the longer a cycle has been absent. We close with guidance you can use today—loop in a sports-savvy registered dietitian, protect your sleep, build stress tools before you’re overwhelmed, and treat your menstrual cycle as actionable data.

If this conversation helps, follow the show, share it with a friend who trains, and leave a review so more active women can find evidence-based fertility support. Your body can be strong, well-fed, and ready to conceive—let’s get you there together.

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Transcript

Welcome And Focus On Fertility

SPEAKER_00 0:07

Hello everyone and welcome to the Barbell Mamas Podcast. My name is Christina Prevett. I'm a public floor physical therapist, researcher in exercise and pregnancy, and a mom of two who has competed in prostitutes, powerlifting, or weightlifting, pregnant, post-partum, or both. In this podcast, we want to talk about the realities of being a mom who loves to exercise. Whether you're a recreational exerciser or an athlete, we want to talk about all of the things that we go through as females going into this motherhood journey. We're going to talk about fertility, pregnancy, and postpartum topics that are relevant to the active individual. While I am a pelvic floor physical therapist, I am not your pelvic floor physical therapist and know that this podcast does not substitute medical advice. All right, come along for this journey with us while we navigate motherhood together. And I can't wait to get excited. Hello, everybody, and welcome to the Bar Bell Mamas podcast. Christina Prebbitt here, and today I want to be talking a little bit about fertility. I'm going to be staying in my lane here and really talking about health promotion and fertility, things that I think are important for you to know, things around exercise and fertility that oftentimes can be slightly potentially misinterpreted. And what I would like my patients or my people to know if they are trying to get pregnant in 2026. Firstly, let's kind of talk about the menstrual cycle. And one of the most important things with trying to get pregnant is to have a regular cycle and to know that you are ovulating. Now, a lot of our recommendations around or decisions around the day that people are ovulating is based on an average length 28-day menstrual cycle. If that is you, that's great because then you can directly apply that counting method or calendar method of knowing when to ovulate or when you are suspected to be ovulating to yourself. But also know that if you are not a person who is in a 28-day cycle and you are a 30 or 31-day cycle, et cetera, um, you may not have the individualized, personalized information for you. So if we go, if you're cycling every 28 days, the estimated ovulation date is between day 12 and day 14. Some people are late ovulators, some individuals are early ovulators. But the first thing that individuals need to know if you are trying to get pregnant in 2026 is do you have a regular cycle and are you ovulating? A lot of people start their conception journey just trying to track the days, knowing that you may have to, if you are a shorter cycle, it might be a little bit shorter or day 10 or 11. If you're a longer cycle, it might be day 15, 16, etc. But just kind of going based on calendar. If you are trying for more months and it is not happening for you, then individuals may be checking things like temperature and changes in cervical mucus consistency as a way to get an idea if they are ovulating, or use the ovulation strips that you can get on in the pharmacy at an over-the-counter drugstore. Those are all methods. And so that is number one. Reasons why you may not be um in that regularly cycling uh calendar method, or may why that might not work, is if you are not regularly cycling. Gosh, that was a jumble of words. It is early. Um, so if you are one of those individuals, what might be causing you to have some um dysregulation or irregularity with your cycle? Almost all of these are going to be a reason for you to reach out to your medical providers and try and see what options for treatment or intervention are there for you. But anything like fibroids, endometriosis, ovarian cysts, or polycystic ovarian syndromes are all fertility potentially impacting conditions and may show up in a variety of different signs and symptoms, but with menstrual cycle irregularity. In the health promotion or exercise space, um, low energy availability, which is a cause for relative energy deficiency in sport, is a very common reason for menstrual cycle dysregulation or inovulatory cycles, where you are not releasing an egg. In reds, this is previously called female athlete triad, but it is a condition where the amount that you are fueling your body is insufficient for the demands that you are placing on it between your basal metabolic rate, your activity throughout your day, and then also with your exercise. When we are thinking about relative energy deficiency in sport, this is going to come up again later on in this episode, but it may be a reason why highly active individuals are having difficulties successfully conceiving. And so it is something that we want to place on our hypothesis list. And while most frequently discussed with individuals who are highly active, it is also something there's discussions about how low energy availability can also be present in disordered eating or eating disorder, individuals who are chronically dieting or trying to lose weight, um, and other scenarios where you may be unintentionally underfueling with or without also a high amount of physical activity or exercise in tandem with that. When we are thinking about our preconception likelihood and our opportunities to optimize our fertility chances, a lot of conversation goes into our health promotion buckets. All of these things that are gonna make our body healthy, there is a lot of conversation about those keeping our eggs healthy as well. Interestingly to note, though, our research on health promotion for fertility in women is less strong than the magnitude of improvement or the positive vibes, positive capacity of improvement for men. The reason why is that for women, we have all of the eggs that we are going to have throughout our lifetime at the time that we are born. What that means is that a lot of our health promotion initiatives definitely our body be more metabolically healthy and stronger, more capable. It also can reduce any of that low-grade inflammation that is such a driver to issues around our body. But it is a snapshot of your health indicators across your life. This is in comparison to men who have their sperm constantly recycling, and the lifespan of a sperm from it's gonna be a sperm to it's being recycled and isn't being used is about three months. And so that 12 weeks, if men increase a lot of their health promoting factors, like removing alcohol and increasing their physical activity, getting better sleep, et cetera, we are seeing these pretty big changes or relatively bigger changes in sperm parameters like motility and volume that are going to be a positive influence on fertility and likelihood of conception as compared to women. Now, why I bring up the male side, number one, it's not fair. I totally agree. Um, but also much of the fertility conversation and the idea around optimizing your health before getting pregnant, these conversations are often like central to women. And 30 to 50% of fertility issues occur because of at least in part male-related fertility factors. And so it's really important that both you and your partner are having these conversations together. Now, on the health promotion side of things, we do see some positive improvements. For example, we have lifestyle intervention RCTs that are working with individuals with overweight, obese, or PCOS and see an increase in pregnancy rate for those who are taking part in a lifestyle intervention program that has a physical activity and a nutrition education component. And so this is not to say that getting healthy isn't worth it. However, I want to remove you from the shame, blame, stress, or belief that if you were just healthier, that this would happen. Fertility is multifactorial. Ideally, we are pouring into our health promotion buckets our entire life. Um, but also there is so many things that relate or cause changes in our health behavior that are outside of our control. So, yes, when we are thinking about physical activity, trying to get moderate to vigorous physical activity and hitting our exercise guidelines is considered beneficial. Um, and reducing sedentary time also beneficial. We have some preliminary data that's looking at the Mediterranean diet as something, especially in individuals with overweight or other endocrine or hormone impacting type of gynecological conditions that it might show some benefit. Side note, I freaking love the Mediterranean diet. One, it's so tasty. Two, all of our research in pregnancy postpartum and across the lifespan is showing just how beneficial the Mediterranean diet is. Um, so good. I've been definitely down a pipeline of like fiber in our diet and colorectal cancers in younger individuals. My husband thinks I'm hiding chia seeds and everything. Kind of am. But side note, the Mediterranean diet is just something that is such an easy uh kind of framework of nutrition. And totally selfishly and random personal side note, I am a huge fan. And so Mediterranean diet. The last kind of health promotion bucket that I think is important to talk about is some of um, I'm gonna pronounce her last name wrong, Shalep's work from her PhD was starting to investigate the role of stress in ovulation and the menstrual cycle. And what we are starting to see is that those who report having high amounts of overwhelm, anxiety, or stress are more likely to have an inovulatory cycle. Now, that said, you're probably thinking, Christina, great, I just have to stress less. I can't control some of my sources of stress. And you are absolutely correct in that. It is how we recognize the stress that is being applied to our bodies and how we work on positive coping mechanisms for that stress. And ideally, we take a preventative lens to those practices instead of waiting until we're in complete overwhelm to start leaning on some of those practices. There is a new RCT. I haven't been able to jump into it um yet, and so I can't really report on the results, but that was thinking about mindfulness and using a guided meditation app to help individuals who are going through their an infertility journey, because we also know for those who are struggling with infertility and use of assisted reproductive technologies, there's financial stress, but there's also emotional mental stress, there's trauma responses, et cetera, that come in when working with individuals going through assistive reproductive technology or struggling with infertility. And so we are starting to have individuals who are recognizing how stressful trying to get pregnant can be, how stressful life is in general, um, and really um working on preventatively or trying to mitigate some of those negative health consequences because of that stress piece. Okay, so those are kind of our health promotion buckets. We have physical activity, we have nutrition, we have, you know, sleep stress are kind of linked in together because individuals with high stress tend to sleep less and have insomnia. Where is this relationship and why is it often that people will get the advice to do less vigorous intensity exercise as they are thinking about trying to conceive? I've had a lot of people who have reached out to me saying that, you know, their fertility provider said that CrossFit isn't recommended or marathon training isn't recommended in pregnancy. So, first, I want to kind of describe where our relationship is right now around physical activity and um fertility. When we look at our systematic review level data and when we compile all of this data together, we are starting to see what we call a J-shaped curve. What that means is that when we look at rates of infertility and successful conception, um, when you move from sedentary, completely sedentary and low physical activity, into moderate amounts and doses of physical activity, we see an increase in the likelihood of successfully getting pregnant. This is great. So we see this big transition, which is fantastic, where we want to move people from not doing any physical activity to doing some and knowing that what is good for the body is good for the uterus. And there is this positive trend that has been consistently established in the literature. What has been less consistently described, but has been interpreted in a variety of different ways, is that those with extreme or very high training volumes may have an increased risk of infertility. And I was at female athlete conference in 20, was it 2025? Oh my gosh, it feels like it was years and years ago, but it was definitely last year. Um, and there was this discussion around the athletic window and the fertility window directly overlapping individuals who are in their athletic careers waiting and then finding out that they're struggling with infertility and this can conversation around fertility preservation and struggles with infertility with female athletes. What we are seeing with that though, and one of my most important criticisms of that data is that one, the vast density of our research is not in the vigorous intensity zone. What I mean by that is that for you know, every one study in vigorous intensity exercise, we may have four or five in moderate intensity. Why this matters is it means that a smaller number of studies are pulling the data and it's easier for bias to come into those studies. So it is important for us to interpret this very carefully when there is such a change. And what we know is that in our research and exercise, the vast, vast, vast majority of studies are done in low to moderate intensities, right? And it's why so much of my research looking in vigorous intensity exercise has been so quickly picked up because we really don't have anything to inform on the vigorous intensity side until the last, you know, couple of years. So that's number one. Number two is that none of the studies in the vigorous intensity side controlled for the fueling aspect. When we look at reds, and I introduced reds earlier, I said it was coming back, it's coming back here. When we look at those who are in endurance sports and those with high training volume, some estimates put that 50 to 58% of these athletes can be at risk for or have developed low energy availability. When those individuals have reds or low energy availability, what essentially happens is your estrogen blunts. It really drops. And estrogen is a really important marker for ovulation, right? So in our follicular phase of our menstrual cycle, estrogen will increase until it hits a critical threshold that triggers lupinizing hormone to surge. That lutinizing hormone surge is what we check on those ovulation strips and is an indicator of ovulation coming or having or ovulation being in the works. If we have a person with reds, that estrogen drops. And when estrogen drops, we don't have an LH surge. And this makes a lot of sense, right? If your body is getting these signals that, hey, you are not eating enough to just keep us healthy, there is no way your body is going to be able to handle the increased metabolic demand of a pregnancy. And as you get into the second and third trimester, the amount of calories taken in just from your basal metabolic rate start to have this stepwise increase to, you know, estimates are between 500 and 600 calories extra demand when you are in the third trimester. And what this now means is that you are more likely to have an ovulatory cycles if you are a vigorous or high volume athlete. And that might be the reason versus the exercise itself, right? And I've had clinically so many stories of people who weren't ovulating, and so they went into ART, and then there's a lot of, you know, misunderstanding of what you can and cannot do from an exercise perspective. Very commonly, people are told to not exercise during their reproduct ART journey or IVF journey. So what ends up happening is they drop their caloric expenditure. And I've had clients crying to me, being like, I think that's what happened. And I didn't maybe need this. And she ended up getting pregnant in a lot of these situations because exercise can drop in between kiddos, et cetera. Sometimes these individuals end up not needing IBF for their subsequent pregnancies. Now, of course, this is not everybody, and I don't mean to over-extrapolate based on clinical stories, but what I am saying is that it's really important to investigate when we are looking at this data on high or vigorous intensity exercise, the the amount of fueling and if you are fueling sufficiently in order to able to withstand or handle that high training volume and the increased demand that would be required in pregnancy. What we see is that when we control for that and we have individuals who we know have normal ovarian function, there is no increased risk based on training volume when those things are equal. And now this might be a chicken or the egg argument, and this is not um based solely on fueling. However, it Important for us to recognize that there is a significant confounding variable in that literature. And so if I was working with somebody, we I would be working alongside my obstetrical colleagues. But if I knew that somebody was trying to get pregnant in that early, like kind of in that preconception window, one of the things that I would be counseling on is just nutrition and maybe getting that referral to a registered dietitian to ensure that they are setting themselves up for the most amount of success. And I will always do that first before trying to take exercise away, right? Because I know that exercise is a coping mechanism. I know that it feels really crummy when you feel like you're not even pregnant yet and you have to start getting rid of things that you really love to do. And so my first step is that referral to RD and making sure that people are fueling appropriately. If anybody is asking me any questions about this relationship between exercise and fertility. And so I think that's really important. Last thing that I'll talk about in this podcast episode is around if you are one of those individuals who thinks, huh, I may not be fueling appropriately, what can I do about it? And I just want to talk about this really cool study that I think is really neat called the Refuel Study. So these are individuals with um who have a high training volume, lots of exercise, but they're university age students and they lost their period. So they had secondary ammonorrhea. They got their period before the age of 16. Um, if you get your period after 16, it's called primary ammonorrhea. So a delayed start of your cycle. These individuals were in secondary. So they were regularly cycling and then they lost their period. What they did was obviously fits my bias, is that they kept exercise even and didn't make any recommendations around training volume, and instead started with nutritional counseling aimed on bumping up their caloric expenditure to try and get menstrual cycle recovery. This is the first study that has looked at using health promotion interventions to try and gain regularity in the cycle, which is very cool. What they found was that though for those who got their cycle back, on average, they were getting 330 calories more, plus or minus standard deviations per day. And on average, gained about 5.7 pounds. I mentioned the weight gain because it happens in almost all cases of menstrual psycho recovery. And that in in and of itself, for somebody who has a struggle with brought body image, self-esteem, relationship with food, uh is something that you may need to untangle and work through. And that is something that you would set an expectation for in the idea that you were doing this in order to get your cycle back and then to get pregnant following. When we they did follow-up studies, and this was just published in the last couple of months, what they looked at too was how long it took people to get back their cycle. And they kind of showed this time pattern where the longer you haven't had your cycle for, the longer it took to recover. And I think that makes a lot of sense. But from a counseling perspective, too, if you're an RD or if you're in the obstetrical space, setting that expectation that, hey, you haven't had your period for three years, it is gonna take a little bit of time with this nutritional counseling piece in order for us to know if this is something that is gonna be truly helpful. Um, and so, you know, if that is you, thinking about this earlier rather than later is gonna be something important to be thinking about. When I kind of reflect on where we're at in 2026, it truly is that the menstrual cycle can be such a pivotal snapshot into the health of women and understanding your cycle ovulation, menstruation, understanding how to respond and auto-regulate from your cycle, understanding what it could mean when your cycle goes away, and then knowing those resources to reach out to, those people to refer yourself to, if you are looking for help in that arena, I think is really critically important. And then if you are starting to investigate this with the goal of successful conception, starting that earlier rather than later is definitely something that's going to be beneficial. All right, everyone, I hope you all found that to be helpful. There was actually just for anyone who is a research nerd like me, there was just a brand new two-part consensus statement that was released in MSSE by the Female Athlete Triad Coalition, that it's super in-depth, it's hundreds of pages, but it really does do a nice job of updating on some of the research, what we know and don't know about Reds, and specifically looks at adolescents as well. If you're a mom who is thinking about having your daughters in sport, um looking at that and making sure that they're setting themselves up for success as well. Um, not just for their performance as kiddos, but also thinking about their life and their fertility and all those types of things, I think is as a parent was something that was really interesting for me to be reading about as my daughter is thinking about starting pre-comp gymnastics. And so definitely a type of sport that is at risk for reds because of the culture around sometimes being smaller equals um being better. Though Simone Biles with her super powerful legs and strong body are starting to dismantle that a little bit. But um, just kind of on my radar as a clinician, as a mom, as someone who has had reds and as um somebody kind of, you know, hopefully raising a new athlete, um, it's definitely something to think about. All right. Have a wonderful rest of your week, everyone, and we will talk to you all next time.