Why do women lose their periods when they work out?

Q: Why do women lose their periods when they work out and lose body fat?

A: When a woman stops menstruating, it?s called secondary amenorrhea. Primary amenorrhea is when menstruation doesn?t begin around the time of puberty.

Secondary amenorrhea is a perfectly normal condition during pregnancy or after menopause — including surgically induced menopause — but it often indicates a problem when it occurs in other circumstances.

A number of conditions can make periods stop, including anorexia nervosa, hormonal disorders, stress, chronic illnesses, rapid weight loss or gain, extreme exercise regimens and very low body fat or body weight. It?s not known exactly how those last three may cause amenorrhea. They somehow disrupt the hormonal functions that drive the menstrual cycle.

Secondary amenorrhea is a common problem among athletes, especially those women and girls involved with demanding competitive sports that seem to mandate slenderness, such as gymnastics. Some women may be pleased that they don?t have to bother with periods, but secondary amenorrhea can cause long-term complications, including infertility, osteoporosis and even heart disease.

Women and teens who miss several periods should see their physicians. It?s important for amenorrhea to be diagnosed properly, with an eye toward identifying the cause or contributing factors. Treatment depends on the underlying problem. In some cases, it may be as simple as reducing the exercise load and improving the diet.