Regular aerobic exercise has significant cardiovascular benefits, including a reduction in incidence of and mortality from coronary artery disease--probably because of positive effects on blood lipid levels and blood pressure. Aerobic exercise can also be an important adjunct to a weight-loss program. Many persons who continue an exercise program do so because of its positive mental benefits, including reduction in anxiety and depression and modulation of stress levels. Aerobic exercise has a place in the management of diabetes, pregnancy, and aging. The problems associated with aerobic exercise are minimal compared with its benefits.