When you stop having monthly periods, it is known as amenorrhea. Here are five important exercise-related facts involving the condition…:

1. Exercise Causes Amenorrhea When the Body Enters a “Starvation State”
When women stop having monthly periods (“amenorrhea”) due to excessive exercise, there’s a problem. It is not just the amount of exercise that influences the menstrual cycle, but certain types of exercise, specifically those associated with low body weight. Long distance running and ballet dancing are more likely than others to cause amenorrhea, for example.

The combination of low body weight and intense exercise causes amenorrhea if the body believes it is in a “starvation state.” When the amount of energy expended during exercise is not balanced by adequate nutritional intake, the body begins to shut down organ systems that are not absolutely essential for survival. This includes the reproductive system. If a woman’s body believes it is in a “starvation state”, it makes sense that it would also feel it is not the right time to carry a pregnancy.

2. Exercise Causes Release of “Stress Hormones”
Even among female athletes that train hard and eat plenty, amenorrhea is common. The biological explanation for this lies in the release of “stress hormones” that are part of the body’s normal response to exercise. These “stress hormones” are similar to those released during “fight or flight” situations, and are also what makes people feel so good after exercising (post-workout euphoria). Unfortunately, these “stress hormones” interfere with the brain’s production of the reproductive hormones necessary to keep the menstrual cycle flowing.

3. Exercise-Induced Amenorrhea Has Long-Term Health Consequences
Most women actually don’t mind it so much when their periods stop coming. And in fact, menstruation can be a big inconvenience, particularly for competitive athletes. But many women are not aware of the serious long-term health consequences of exercise-induced amenorrhea.

Because of the altered production of reproductive hormones, women with exercise-induced amenorrhea are estrogen-deficient. Estrogen is one of the most important female hormones, and when there is too little of it, the health risks include infertility, atrophy of the vagina and breast, and osteoporosis (which can lead to fractures of the spine, hip, and other areas). Prolonged exercise-induced amenorrhea may also increase the risk of heart attacks later in life.

4. Exercise-Induced Amenorrhea is a Diagnosis of Exclusion
Prior to starting treatment, women with exercise-induced amenorrhea should be evaluated by their doctor for other possible causes of irregular or absent periods. These include pregnancy, thyroid dysfunction, prolactinomas (benign tumors of the pituitary gland), and premature menopause. Since exercise-induced amenorrhea is considered a diagnosis of exclusion, one cannot assume the exercise is the culprit until every other potential cause is eliminated.

5. Treatment Restores Estrogen to the Body
Once the diagnosis is confirmed, the main objective of treatment is to restore estrogen levels to the normal range. In many women, this can be accomplished by increasing caloric intake so that the body exits “starvation state.” In women who are reluctant to increase their calories, estrogen can be given in the form of birth control pills or patch. It can also be given as hormone replacement therapy, similar to that used by postmenopausal women. Such treatments will protect a woman’s bones from fractures due to osteoporosis, but will not treat her infertility. Infertility due to exercise-induced amenorrhea can be treated with fertility medications, but if a woman is underweight, optimizing body weight by improving nutritional intake before trying to get pregnant is the preferred approach.