When women compete and train at a high level in sports that prize a low body weight and a high lean body mass, it’s not uncommon for them to stop getting their periods. Experts estimate that this condition -- known as functional hypothalamic amenorrhea (FHA) -- may affect over 65% of female endurance runners. It’s also pervasive among triathletes, competitive swimmers, competitive cyclists, dancers, and gymnasts.

But it’s not talked about. In fact, periods have been a taboo topic in women’s endurance sports for years. That’s a big problem. Missing periods are a sign that hormone levels are off, which can lead to low bone density and stress fractures, and ultimately to infertility and other long-term health complications.

I have struggled with FHA since I started getting more serious about track and cross country running in high school. I’ve had two stress fractures in the past, and while my bone density is not critically low, it is lower than it should be for someone of my age. So after competing at the Ironman World Championships in Kona this October, I told myself that I needed a new goal: learning everything I could about FHA, getting my hormone levels back to normal, and sharing what I learned with my athletes, my training buddies, and my mentors. I took a deep dive into women’s sports physiology and came out of it with a big appreciation for optimizing women’s health in endurance sports. Here’s what I learned:

Fueling is key. The number one cause of FHA is low energy availability, which basically means that your body doesn’t have enough energy reserves to support all of the activities you do plus what it would need to carry a baby. Whether pregnancy is on your radar or not, women are evolutionarily designed to be ready to reproduce at any given time. If the body thinks that it doesn’t have enough energy in reserve for reproduction, it will shut down the menstrual cycle in an attempt to save energy for basic life functions. The problem is that this also shuts off the production of estrogen, which will stop you from building bone mass and lead to the fractures we talked about earlier. So if you have FHA, the first thing you need to do is increase the amount of fuel you’re taking in so you can convince your body that it has the energy required to carry a baby. This can be pretty hard for endurance athletes who train at a high enough volume and/or intensity that they struggle to get enough calories in to replenish what you burn. If you can’t increase your energy input any more than you already do, you may need to reduce your energy output, which brings me to point #2...
Take more rest. Another way to jumpstart a normal menstrual cycle is to reduce the volume and/or intensity of your training. This is important for flipping the low energy availability equation, as well as for reducing cortisol levels, which are another contributor to hypothalamic amenorrhea. Cortisol is a stress hormone that is secreted during exercise and other stressful situations, and while it temporarily helps you to perform your best while training, constantly high cortisol levels send a strong signal to your body that it is not a safe time to carry a baby. If you’re struggling with FHA, you should start by incorporating some intentionality into what workouts you are doing and why you are doing them to ensure that you aren’t unnecessarily piling on volume that keeps your cortisol levels high. It’s also crucial to build a dedicated off-season into the year where you dramatically reduce both the volume and intensity of your training, as well as a recovery week once a month and a rest day every week (while still fueling well during those times). Some experts suggest that women trying to recover from FHA should reduce their training to no more than 8-10 hours a week. These changes can help you build up your energy reserves and lower your cortisol levels.
Life stress matters too. Exercise isn’t the only reason behind high cortisol. Any constantly stressful situation -- work, school, moving, relationships, etc. -- can jack up your cortisol levels to the point where your cycle is impacted, and heavy exercise and underfueling will compound the problem. I’m pretty sure that I personally was under a constant state of high academic-induced cortisol during my four years as a student at Dartmouth, so it’s no wonder that I wasn’t getting a natural period even when I wasn’t training for Ironman distance races. If life stress is a problem for you, it’s important to prioritize stress management techniques, adequate sleep, and unstructured free time so you can prevent your cortisol from being even higher than it would be from training alone. (See our post on life stress here!)
Natural supplements can help. I’m not a doctor and I have no authority to give any medical advice, but I’ve had success with some natural hormone-regulating supplements for stress management (try HPA adapt) or menstrual cycle regulation (try Vitex, Femmenessence MacaHarmony, and Acetyl-L-Carnitine). They work best in the context of other fueling, exercise, and life changes and probably won’t fix FHA on their own, but they can certainly support you in moving things along as you’re working on recovering a natural period.
Birth control is NOT the answer. This one is important. Many doctors will recommend that you go on an oral contraceptive pill (OCP) if you have FHA because it forces hormone fluctuations that will cause a withdrawal bleed on a “standard” 28-day cycle. However, this is not a natural period. Medical experts who focus on FHA have come to the conclusion that birth control doesn’t actually help you rebuild bone mass, and it can give you a false sense of security because you don’t know if your body can actually support a normal cycle or not while on the pill. If you think you might have FHA, and you’re on birth control, you should talk to your doctor about these concerns and consider going off the pill to see whether you menstruate naturally. (This one hits close to home; a doctor prescribed an OCP for me when I initially stopped getting my period in high school and I stayed on it for four years. I ended up with a stress fracture twice during that time.)
Talk about it! A lot of women with FHA don’t talk about it with their coaches or teammates. But talking about it with people who are most directly involved in your athletic endeavors is the first step to developing a plan to fix FHA. If you’re working with a coach or team that refuses to support your attempts to prioritize your own health, you’re probably working with the wrong people. This was something that was difficult for me to do at first, but the outpouring of support I have received from everyone who has been looped into my journey has been really encouraging. I’ve also realized that FHA is so much more common among my broader athlete circles than I originally thought, and that has made me even more eager to keep the conversation going.

With a dedicated off-season in which I fueled well and often, set hard limits on my weekly training hours and metrics, prioritized getting enough sleep every night, started taking hormone-regulating supplements, and actively practiced stress management techniques, I ended up getting back a normal cycle within two months after not having one for almost six years. I’ve been tracking my cycle using the FitR woman app and have been modifying my training accordingly, which I highly recommend for all female athletes. While I’m only just starting to increase volume and intensity for next season -- which will most likely not include a full Ironman because grad school is busy and wedding planning is busier -- I’m confident that I’ll be able to stay on top of my health and make adjustments if anything goes awry. More importantly, I think I’ve gained a better perspective on women’s sports physiology in general, and I hope that this will help me optimize my athletes’ and teammates’ experiences in endurance sports.

The good news is that periods are finally starting to lose their taboo in the world of endurance sports. Elite athletes like Lauren Fleshman, Elyse Kopecky, Tina Muir, Sarah True, Ruth Winder, and more are speaking out about FHA and/or the more general fact that women actually have periods. So any women out there who are struggling with an irregular or missing menstrual cycle, or who have a regular cycle but feel uncomfortable about even talking about in the context of endurance sports, should know that times are changing for the better. Periods are here to stay whether we like it or not, so we might as well start talking about them.

P.S. More good news: the menstrual cycle does not actually have to be a performance limiter! I recommend Stacy Sims’ book, ROAR, for insight on how you can use your cycle to your advantage and optimize your training around fluctuating hormone levels.