ANSWER: No. Few studies have found any difference in body composition amenorrheic and eumenorrheic between athletes. Physiological systems, including the reproductive system depend on energy availability, which is the amount of dietary energy remaining after exercise for all other physiological functions. Resting energy expenditure is about 30 kcal/ kgFFM/day. When energy availability is less than 30 kcal/kgFFM day, the brain activates mechanisms that reduce energy expenditure. In the reproductive system, the pulsatile secretion of gonadotropin-releasing hormone by the hypothamus slows down and this suppresses ovarian function. Reproductive disorders have been induced, prevented, and reversed experimentally by changing energy availability without any change in body composition. Because menstrual disorders are also symptoms of many diseases, however, a medical examination and endocrine measurements are needed to properly diagnose them.