Hormones, periods, and peak performance in women’s sport

For too long, missed periods and severe diets were the norm for women who wanted to compete in endurance sports. That had severe consequences for their performance and long-term well-being.

As a medical doctor and academic researcher, Anna considers a regular menstrual cycle a vital sign of female health. Female athletes whose hormones are out of balance are more susceptible to injury, more likely to get sick, less able to train, less able to recover, and less able to compete to their highest potential year after year. In the long term, they are more likely to suffer from chronic conditions such as osteoporosis and cardiovascular disease.

We asked Anna for her best advice for female athletes who want to compete at their best while maintaining healthy hormones.

Read on to learn more. And if you are an athlete concerned about your own hormonal health, please consult your doctor and a trained dietician.

The first thing that female athletes need to understand is that female hormones like estrogen and progesterone are important for reproductive health, but also for various other health systems, like your immune system, metabolic health, and cardiovascular health.

When women lose their periods, as we do in menopause, our risk of cardiovascular disease increases, the risk of osteoporosis or bad bone health increases. Everything gets worse. We just don’t want to reproduce that in young people.

If your estrogen levels are too low, it is a physiological sign that your body is surviving a starving situation or a stressful situation. It is an adaptation your body makes. The problem is when this is maintained over time. Your body goes into a survival mode, which makes you less effective at building strength and maintaining overall health.

For general health, the biggest concern is bone mineral density. We are just not able to build up normal, strong bones without healthy hormone levels. At my clinic, the first indication we will usually get that someone has bad hormonal health will be an unexpected stress fracture. It is especially important for young women to avoid this.

There is a period, when you are growing, which in women is about 14 or 15 years old until age 20, when you achieve the peak of your bone mineral density, which you will need to sustain you for your whole life. If, within this timeframe, you don’t have your period and you don’t have good hormonal health, you will miss your opportunity to have strong bones for the rest of your life.

Sometimes, in sport, people tend to think you can be a professional athlete and pay the price now, but then get healthy again after, and that’s it. And that’s not true. There are long-term effects. If we do a bone density scan of a rider who has been without her period for four or five years, we see the bones of an old woman. Even if you recover your hormonal health, you may pay that price for the rest of your life. For me, that is the most important reason why I want to have a positive influence on these young girls. I don’t want them to miss that opportunity, because they won’t get a second one.

There is also increased cardiovascular risk and a drop in immunity that can develop over time. You will fall into a circle where you’re not healthy, so you get sick very often, and then you get fatigued, because you cannot adapt to training. Then, one day, you wake up, go running, and break a bone spontaneously, as if you were an 80-year-old woman.

Female hormones have a very, very strong influence on muscle synthesis, recovery capacity, and metabolic pathways. Step one is being healthy. Not having estrogen at a younger age means potentially getting sick. Second, you want your hormones to be balanced, so you can perform better, because you can better adapt to training.

You will adapt better if you have a normal level of hormones. That means that your body is not stressed metabolically, which means that it’s ready to train today and be better tomorrow and years into the future.

A pattern that we too often see is a rider who is not very conscious of the importance of her hormones, who loses a lot of weight, and shines for one season. But then, she is not able to maintain that level ever again, because her body is just so stressed and falls into a cycle of fatigue instead of recovery. It is quite cruel what happens.

Without your hormones, you cannot adapt to training. You can survive, but you can only survive for a given period of time, which, from my experience, is no more than one and a half seasons, after which you never come back to your previous level.

There are multiple variables. First of all, there is a lack of communication. It’s an uncomfortable conversation to have. I remember a statistic I saw from the Tokyo Olympics that only 10 percent of the athletes were talking about menstrual health with their coaches. We are talking about Olympic athletes who are pros. This means that younger athletes are just not having these kinds of conversations. It is very difficult to identify if there is a problem if we don’t ask about periods, just as a coach would ask, how is your sleep? Are you sick? Are you fatigued? We need to get over the taboo and get better at communicating about our health.

Second, for a long time we have got used to seeing a standard body shape for female athletes – for men too – that does not have much to do with athlete health. The standard body image is very skinny and not very strong and very thin.

That is changing, especially in the last five years. You could see it at the Olympics. Even aesthetic sports like artistic swimming or gymnastics are evolving towards a body shape that is really, really strong, and those athletes are breaking all the records. Our image of an athletic body is not always the image of a healthy and strong body, and I think this also has an influence.

Third, there is just a lack of knowledge. We have been so slow to think about women as a different biological sex in sports and not just as men who are smaller. We have just reproduced what we were doing in men with females, ignoring the fact that we are quite different and have different needs. This, for sure, is changing, but I think that we as a scientific community need to accept the responsibility that we have been quite slow to acknowledge the fact that women are different and have different needs, and we need to adapt how we think about health and performance and nutrition to that.

I think that it is too reductionist to think that it’s only about weight. When are you eating? How are you distributing this food around your training? What is your periodization plan? For how long are you going to stay at a given weight, and why? How is your body composition?

Yes, improving hormonal health often involves gaining a little bit of weight, but that is not always the most important thing. Most of the time, it’s about doing things as your body needs them to be done, listening to your body and understanding your body, your female body, as something different to a man’s and understanding its needs. It is less about weight per se and more about how you get there.

If we take this reductionist view of calories in, calories out, just imagine that we want to intake 3,000 calories. You could do that by just not eating carbs and eating massive amounts of protein and fat. Or, you can eat a rational number of carbs with the same number of calories, but you’re just eating them in a proper way. When women cut carbs, they have a lot of problems.

All women need carbs to function. It is not only about weight, but how you approach that weight.

Most of the time, it is about food distribution and not fasting for too long. It is about understanding that the female body is typically capable of having children, and this means that we are energetically very sensitive, because we are animals that could potentially get pregnant. So our body requires energy in case we get pregnant. That’s quite important and a big difference from men.

As a scientific community, we are starting to understand periods as a vital sign of hormonal health. Did you miss a period during the past three months? Are your periods painful? Do you need to change your menstrual hygiene every two hours or less? Do you have pre-menstrual symptoms that force you to change your training or lifestyle? This is a basic checklist, and if the answer to any of these questions is yes, you should seek attention, but it is also really important to understand your individual patterns.

TrainingPeaks allows you to track your period and compare that information with your training data, which is very useful. You need to monitor your cycle, but also how you feel and how you perform during its different phases.

Some women perform very well when they are ovulating, for example, and others perform super well the first day of their period, while other women might only struggle two, three days before their period. It is quite individual. That is why you need to track your periods to understand your patterns and anticipate them.

Some women experience bad sleep a few days prior to the start of their period, and feel more sleepy during the period. In the luteal phase or during menstruation, the early folicular phase, some riders need to hydrate more in warm temperatures to maintain hydration. Some riders may find carb intake during races a bit more difficult in the first days of the period, or they may need to go to the bathroom more often. During the luteal phase, some athletes experience carb cravings that can be easily prevented by increasing their intake. Although performance is multifactorial, some athletes may find that they feel more comfortable in training around ovulation. Others feel bulletproof when they get their period. It is variable, but there is usually a pattern.

There is no rigid approach. It’s not as simple as you are in the follicular phase, so you can train more, and in the luteal phase, you are weaker. You need to understand your pattern and adjust your training. If you want to do a VO2 max day, and you know you are going to feel bad because it is scheduled the day before your period, just change it. Anticipate that. Coaches need to know that there is not one pattern for all girls. That is a mistake we made in the past, assuming that girls function the same way. They don’t.

It is also important to understand that hormonal health is not just about having periods or having periods every month. An Olympic athlete might say, “I usually miss two periods before a big international competition.” No problem, so long as you get back into your regular cycle. You just need to understand how you operate and empower yourself. Health can mean different things to different athletes. In the team, we monitor this very closely with blood tests, bone mineral density scans, etc. Maybe you have a rider who has six periods in a year, but she’s healthy and she doesn’t need to stress about it, because we are monitoring her health and taking care of her health. There are lots of ways of being healthy. I wouldn’t want a rider to be stressed if they don’t have their period every month, but if they don’t have one for more than six months in a row, that is not something that they should sustain.

First of all, this is not a disaster! It’s something that many female athletes have experienced, and with the right care and some simple changes to your training and your diet, you will soon be back to your regular cycle. Talk to your doctor. Talk to your nutritionist. And talk to your coaches. There is nothing to be ashamed of. Let’s evaluate how your training is going and your nutritional strategy in relation to your training. That is the first thing you should do: just analyze what’s happening. What has changed?

You need to understand your individual patterns. I’ll sometimes come across an athlete who has been competing for ten years and ask, how long are your periods? And they just don’t know. Because they don’t track. Maybe they wear a Whoop and track all of their training, but they don’t track their periods. My most important advice for young athletes is to pay attention to your cycles, understand how they go, for how long they last, and when they occur.

Then, when something goes wrong, you will be very aware of it, because you’re used to monitoring them, and you will be able to find out why. Your cycles will change. When you are 15 years old, they probably won’t be very regular. When you are closer to competition, they usually get longer, or you might miss one period. That is not a real problem, because it’s part of the dynamic of the physiology of the female.

But we need to develop a culture where athletes measure their periods, just like they measure their power or other relevant performance metrics.

If you go to your doctor, nutritionist, or coach for help, the first thing they will probably ask is what do your normal periods look like? Then, they will be able to go back and analyze what is going on.

They will probably want to look at your overall energy balance and then look at other stressors like changes to your training or nutrition. Altitude or heat might have affected your cycle. Maybe you are going through a particularly stressful period of racing or just life in general. They may also ask you to take a blood test to better understand what is going on.

Just remember that knowledge is power. When you have identified what is disrupting your cycle, you can make changes and soon be back to your best.

One very important thing to understand is that hormonal health isn’t fixed by contraception pills. That is the biggest mistake that was often made in the past. Athletes were prescribed anticonception pills and had bleeding, so it was assumed that they were having normal cycles. And that’s not true at all. If your internal hormones are out of balance and you take artificial hormones, you bleed every month, but it’s not natural bleeding, and all the negative effects of not having internal hormones are just the same.

Athletes really, really need to be very aware that the problem doesn’t get solved by taking the pill. Especially for bone density, the consequences of not having internal hormones are just the same.

We need to be careful not to make the message too sweet. Sometimes, having your period sucks. That’s the reality. Some girls really struggle with it. Some girls don’t, but some girls really do. And we have resources to deal with that. But to do that, you need to know if you struggle with the heat, if you’re on your period, or if you need more energy intake during the days before your period, because you’re building up endometrium, and so on. There is also the emotional impact. You might have a higher risk of injury at certain points in your cycle. And we have to anticipate that and work on strength training. It is quite complex. It is not like we can just normalize having periods, and you have them, and that’s it. Some women struggle with it, but we do have the tools to make your lives easier and help you perform better around it. The cost cannot be your health, not your short-term health and not your long-term health. This stupid idea that being unhealthy is just the price you have to pay for being an athlete is no longer valid. We need to do a better job of taking care of athletes and helping athletes take care of themselves.