When too much exercise makes women sick

If women don’t have periods, have little energy while exercising and are becoming increasingly thin, the diagnosis may be RED-S syndrome. The disease, which affects recreational and professional athletes, is rarely recognized.

Female physique has not been the focus of sports science for decades; studies are primarily carried out with male athletes. It is therefore only logical that disorders of the female cycle have long been overlooked or even welcomed, as “disturbing” side effects such as menstruation also disappear.

It was not until the 1990s that the term “Female Athlete Triad” was coined. So-called stress fractures in female athletes are alarming – the result of bone damage and osteoporosis, which is usually more common in women after the menopause. Researchers describe the disease as a symptom complex that is characterized by excessive training in combination with too little energy intake, osteoporosis, i.e. loss of bone mass, and disorders of the female cycle.

Claudia Römer from the sports medicine department at the Berlin Charité has been working on the phenomenon for several years. Because she sees shockingly often competitive athletes, but also ambitious amateur athletes, who are affected in one way or another. Based on international studies, Römer estimates that up to 60 percent of athletes in competitive sports – depending on the sport – could be affected. “We also see very high percentages of over 40-50 percent among ambitious amateur athletes,” she says in the ARD documentary Knowledge .

A Leipzig study recently determined how common cycle disorders – an important indication for the Female Athlete Triad – actually are among German competitive athletes. Horrifying result: Over 30 percent of the endurance athletes surveyed said they were affected.

In research, the Female Athlete Triad is now classified as a manifestation of RED-S (Relative Energy Deficit Syndrome). An energy deficit that has existed over a long period of time is responsible. This means that the body’s fat reserves are used up and too little new energy in the form of food is supplied.

This can happen unintentionally in endurance sports, for example due to a rapid increase in training volumes without a corresponding adjustment in calorie intake. Or – typical in recreational sports – through overly ambitious weight loss in conjunction with excessive training and/or a calorie-reduced diet.

Men can also be affected by RED-S syndrome: However, the problem is much more common in women because the female body reacts faster and more sensitively to the energy deficit.

Difference from anorexia

RED-S differs from anorexia in athletes (anorexia athletica) in that it is not the mental component that causes the clinical picture, i.e. problematic body image or addictive behavior. RED-S syndrome does not have to be accompanied by anorexia, as the energy deficit can also arise unintentionally. However, the organic effects are very similar, and RED-S syndrome can also occur together with anorexia athletica. 

Energy reserves for possible pregnancies

Endocrinologist and gender medicine specialist Alexandra Kautzky-Willer, professor of gender medicine at the Medical University of Vienna, can explain why female athletes react more sensitively to an energy deficit. She researches the differences between female and male metabolism and repeatedly comes across fundamental differences in the “energy management” of the two sexes.

This is not only noticeable in the effect of diets and exercise, but also in diseases such as diabetes mellitus. Kautzky-Willer explains the evolutionary meaning of these gender-specific differences as follows: “In general, women gain weight more easily and have more problems losing weight. Probably because nature dictates that women have an energy store as a reserve for possible pregnancies.”

The development of the Female Athlete Triad can be explained as follows: The body reacts to a too radical loss of fat reserves with a change in the hormonal balance – the cycle becomes irregular, weaker, and ultimately stops altogether. Pregnancy is no longer possible: given the depleted energy reserves, that would be too risky.

Do healthy sports

How many reserves the female body needs to maintain normal hormone levels varies from person to person. As a rough guide, sports medicine specialist Römer recommends that women not have a body fat percentage of less than 15 to 17 percent.

Missing the cycle can have serious health consequences. Römer warns: “By missing a cycle, you ultimately risk that the estrogen level is too low. And since estrogen is also a very important part of bone metabolism, you risk having bone density that is too low.”