Sports and Menstrual Cycle Disruption | FAMM Research Series (Episode 537)

Full Transcript: Episode 537

Lisa Hendrickson-Jack:

In today’s episode, we are diving into the topic of sport and how it affects the menstrual cycle. I found an interesting article. This is an article that I drew from when I was writing the HA chapter of Real Food for Fertility. And the article gets into a really interesting question, which is, you know, which sports are more likely to delay menarche, to disrupt the menstrual cycle? Which sports are associated with more menstrual cycle disruptions compared to others? So without further ado, let’s go ahead and jump into this fascinating topic.

So I always say that the title of these studies leaves something to be desired. They’re not necessarily catchy, but the title of the study — the prevalence of menstrual cycle disorders in female athletes from different sports — that’s basically the overview. And when I was researching the HA chapter, I reviewed many studies. In every chapter we reviewed many studies, but this one stood out because it’s a meta-analysis, so a review of several studies. It really pulls together a lot of data on a variety of different sports and presents it in a way that allows us to kind of summarize and pull out basically the answer to the question of which sports are associated with menstrual cycle disruptions? So we’ll get into it, and I’ll share some of my thoughts and takeaways from the study.

So just to kind of set the stage here, there were 48 studies that were included in the study that covered a variety of different sports. So these researchers were doing a review of a variety of studies, and a research article like that gives us a really interesting insight because it’s not just one study of one particular situation. It’s pulling together a lot of different data to see what we can gather and if there are any similarities. I think there’s validity to all different kinds of research — validity to review studies that pull in a lot of data, and also validity to looking at individual research studies that are looking at a very specific question. There’s a place for all of them.

I think a good place to start is with some general takeaways from the research study and also overall related to sport and how it impacts the menstrual cycle. If we were to look at a couple of the main takeaways, it’s helpful to know that women who are in sport — so teenagers and grown women who are in sports, especially elite athletes — are more likely to experience menstrual irregularities overall. If we were to look at the sports world, women who are active, women who are athletes, women who are elite athletes, that category of women in general, you’ll find more menstrual cycle disruptions overall. And we could group those disruptions into different categories.

The main three that we’ll focus on today are primary amenorrhea — that is in young adolescent girls who have not had their first period by the time that they’re 15 years old, which is typically how it’s defined in the research studies. Secondary amenorrhea occurs when you have a woman who did have her first period and so she has been cycling, but typically it’s defined in women who are going anywhere from three to six months without a period after they had already had a period and of course they’re not pregnant and other conditions have been ruled out. And then the third category is oligomenorrhea — that’s essentially irregular cycles, typically defined as cycles that are longer than 35 days, or if you’re having fewer than about eight cycles in a year.

One of the big takeaways just in general is that women who are active and in sport do tend to have more of these cycle irregularities in all of those areas. Another high-level takeaway is that typically menstrual cycle disruptions are seen at an even higher frequency in sports that have an emphasis on thinness — sports where a woman’s body composition is part of the whole picture. You can think about things like figure skating, gymnastics, ballet — sports where the body composition of the woman is kind of a part of that sport, even just for the aesthetic aspect of it.

I myself loved ballet as a little girl. I was a ballet dancer. And so I experienced that firsthand where there was a preference for girls with a certain body type. They didn’t necessarily say it out loud, but you would notice as a dancer that certain girls would get the parts or the solos, and often it was related to their body type. So it was this unsaid thing that everybody knew.

Ultimately, what we’re getting at when we’re looking at these types of studies is the concept of hypothalamic amenorrhea and various stages. It doesn’t always start at full-blown HA. We can often see some level of cycle disruption or change before it ever gets to that point. But the underlying factor when we’re looking at these cycle disruptions is related to what they call relative energy deficiency in sport. In layman’s terms, it is women who are exercising at a certain level where their activity level is really high, and they’re not necessarily consuming enough food for that activity level. It’s not always something that is done intentionally. For many of these women, it is absolutely not done intentionally.

So what were the sports that were most associated? Overall, they said the prevalence of menstrual disorders among the studies ranged from zero to 61 percent. Some of the studies didn’t really find that there was a high prevalence of menstrual disorders, but some of the studies found up to 61 percent of participants who were involved in those sports did experience some sort of menstrual disorder.

When we look at primary amenorrhea, the highest prevalence was found in rhythmic gymnasts — 25 percent of rhythmic gymnastics specifically. 20 percent of soccer players and 19 percent of swimmers. So the highest prevalence was found in gymnastics, soccer, and swimming.

For secondary amenorrhea, 56 percent of cycling women experienced secondary amenorrhea. Triathlon was 40 percent. And again, gymnastics showed up — 31 percent of women who participate in rhythmic gymnastics experienced secondary amenorrhea.

And oligomenorrhea — boxing had a really high rate at 55 percent. Rhythmic gymnastics again showed up at 44 percent, and then artistic gymnastics at 32 percent.

So right off the bat, we see that gymnastics showed up a lot. Gymnastics, soccer, swimming, triathlon, boxing — they were all associated with a high incidence and high prevalence of menstrual cycle disruptions. What they said in the study is that high physical demands and insufficient recovery, together with long-term inadequate nutritional intake and psychological stress, are potential factors that cause an imbalance in the neuroendocrine process related to the HPO — hypothalamic pituitary ovarian axis — the system controlling reproduction.

They also broke down the results by the type of sport — team sports, what they termed cyclic sports, and then another sports category. They were finding high prevalence of primary amenorrhea in soccer players, secondary amenorrhea in volleyball players, oligomenorrhea in soccer players as well. They said up to 71.5 percent of ice hockey players experienced minor menstrual dysfunction. In what they termed cyclic sports, the highest prevalence of primary amenorrhea was observed in middle- to long-distance runners. Secondary amenorrhea — the highest prevalence was found in middle- to long-distance runners and cyclists. The highest prevalence of oligomenorrhea was observed in endurance athletes. And they also noted that menstrual cycle irregularities were observed in 83 percent of lightweight rowers.

I suppose the takeaway here is that women who are involved in certain sports — and again, not surprising to me — cycling and running, those two sports, when you look at the research and the data, are often associated with a higher incidence of menstrual cycle disruption or hypothalamic amenorrhea in particular, so secondary amenorrhea.

The researchers also noted that among athletes — and not just elite athletes, but overall — there was a trend in scientific literature toward a delay in menarche. Compared to non-athletes, women who were really athletic overall showed this trend toward having a delay in their first period, about half a year or so. They attributed this delay in the onset of first menstruation to the training intensity combined with inadequate recovery, as well as potentially the energy deficit explanation, where the activity level is more than what the food intake is.

Does it mean that women shouldn’t exercise? Obviously it doesn’t mean that. But I do think it shows us that our menstrual cycle really is a vital sign and it really does give us this real-time measure of how our body’s doing. We can talk about the foundations of what we know from the research literature — we know we need sufficient protein, we need sufficient fat, and I would include animal fat in that, because it’s through animal fat that we get our cholesterol, and cholesterol is a precursor to our steroid hormones: estrogen, progesterone, testosterone, cortisol, and even vitamin D. In order for our menstrual cycle to normalize, we need sufficient hormones in order for that to happen, and we do need to feed our hormones.

What do we take away from this? I think you can take away from it that we should be paying attention to our menstrual cycles. Ultimately, it’s not about what we think — it’s about what’s actually happening in our bodies. If your activity level is moderate to high, even if you don’t consider yourself an athlete, if you’re exercising in a vigorous way four or more times per week, you are at that athlete level whether you think of it or not. Are you charting your cycle? Do you know how long your cycle is overall? Do you know if and when you’re ovulating? How long is your luteal phase? Do you experience abnormal bleeding or spotting? Do you ever skip a period? And if you’re tracking your cycle and you are experiencing cycle irregularities — when did those irregularities begin? I can’t tell you how many times I’ve worked with clients where we can see the specific start date of their menstrual cycle irregularities was either when they started incorporating exercise or when they really ramped up their exercise.

Ultimately, your menstrual cycle is really the key to letting you know what your homeostasis is. Your cycle will let you know if you’re doing well or if you’re overdoing it a little bit. If you need to tweak your intake of food, protein, fat, whatever it is, your cycle will give you that information. It’s a really great real-time vital sign barometer that gives you that feedback whether you want it or not.

I think that the study also shows us that it’s not necessarily easy or intuitive for active women to sort this out. If there’s such a high prevalence in women who are cyclists, runners, gymnasts, soccer players, swimmers, then it shows us that it’s not necessarily intuitive. It makes me wonder if there’s not enough emphasis in these sports on ensuring that the women are paying attention to nutrition — if the sport itself is more focused on the outcome. Where is the conversation around nourishing your body and ensuring that you’re maintaining a healthy menstrual cycle, especially for young teenage girls? It’s a huge problem.

I would imagine that the menstrual cycle conversation has never come up in many of these contexts — no information for parents to be aware of so that they could be making sure that their daughters aren’t losing their period if they’re on the soccer team. Because that’s a huge flag, especially for adolescent girls who are also developing. If you are exercising to the level that you can’t even ovulate, then what does that say about your development in general?

That’s definitely a takeaway as well — if you’re not menstruating, that also tells us something about your bone development. If you can’t ovulate, if you can’t manufacture sufficient hormones, if the HPO axis can’t sort itself out to allow you to ovulate, that’s also associated with bone loss. And arguably, if you’re a teenager, it could have a negative impact on your lifetime ability to really create and establish that peak bone mass that we don’t hit until we’re in our late 20s, early 30s.

So lots to think about. More evidence, more research and information in case you already weren’t on the menstrual cycle as vital sign train — I’m giving you even more to add to that. It’s also easy, dare I say, to pay attention to, because we have this sign. Why not look at it and use it to tell us how we’re doing, especially when we’re involved in sport?

If you are interested in the study and want to look deeper into it, I will make sure to link the study in our show notes page at fertilityfriday.com/537. If you’ve been enjoying our FAMM research series episodes and want to catch up on previous episodes, you can find that at fertilityfriday.com/research. I hope you have a wonderful weekend whenever you’re tuning into the show, and of course, as always, until next time, be well and happy charting.