Exercise, sports, and menstrual dysfunction.

With the increasing involvement of women in exercise programs, the physician is faced with more and more questions regarding the effect of exercise upon the reproductive system. Currently, it appears that premenarchal training may have the effect of delaying the onset of menses in some girls. There is no evidence that it delays the other stage of puberty or that it causes any harmful development by this delay. In the postmenarchal woman, strenuous exercise can definitely alter her bleeding pattern. The usual result is oligomenorrhea progressing toward amenorrhea as the exercise increases. This is not a universal phenomenon, however, and other factors such as percentage of body fat, stress, diet, and energy drain also play a role. The menses will usually resume its preexercise pattern after a period of rest.