This article surveys recent research on how and when exercise or estrogen therapy should be used to treat or prevent athletic amenorrhea, osteoporosis, cancer, and heart disease. The suspected causes of each disease are discussed and the benefits and dangers of each form of treatment/prevention are weighed. (JL)

Research has not yet identified the best combination of estrogen replacement, calcium, and exercise for fighting osteoporosis, but clinical experience indicates all are needed to prevent the rapid bone loss that occurs in postmenopausal women. Physicians must encourage women to reduce their risk using all available options. (SM)