Exercise produces a number of changes in the bodies of female athletes, including changes to the production of hormones. One of the possible side effects of these changes is amenorrhea, an interruption of the menstrual cycle. Exercise-induced amenorrhea affects a significant proportion of female athletes, but can often be treated relatively simply.
Primary and Secondary Amenorrhea
Primary amenorrhea occurs when a young woman does not begin to menstruate at a typical age, about 16. Secondary amenorrhea occurs in women who have already begun to menstruate. Amenorrhea -- including a single missed period -- can happen for a number of reasons. Secondary amenorrhea is treated as a serious concern if a patient misses several menstrual periods in a row.
Exercise-Induced Amenorrhea
Amenorrhea is common in female athletes relative to the population at large. A 1999 study in the "Journal of Clinical Endocrinology and Metabolism" collected evidence of exercise-induced amenorrhea from previous studies. It found that while studies suggested that about 5 percent of women suffered from some form of amenorrhea, the incidence was much higher for female athletes. A 1987 study of ballet dancers showed that more than a third suffered from amenorrhea, while about a quarter of runners in a 1982 study showed symptoms of amenorrhea.
Causes
Amenorrhea in female athletes appears to be the result of several factors, including nutritional deficiencies. In non-athletes, amenorrhea is often linked to weight loss, and this seems to be the case in female athletes. A lack of available energy causes the body to shut down certain functions, including production of Gonadotrophin-releasing hormone -- or GnRH -- and low levels of other hormones related to the regulation of the menstrual cycle. This is one of a group of conditions known as the "female athlete triad," including eating disorders and bone damage, which result from inadequate nutrition.
Treatment
Exercise-induced amenorrhea can be treated using a combination of methods. Eating more can can help female athletes get necessary nutrition, including vital minerals such as calcium and iron. Establishing the correct diet is a longterm process that requires athletes and medical professionals to work together. In some cases, hormone replacement therapy may be useful, while oral contraceptives can help to regulate the body's hormones. Amenorrhea may take some time to reverse, even once treatment begins.
