A decline in maximal aerobic exercise capacity occurs across the adult age-span, accelerating in later years. This age-associated decline in aerobic capacity is accentuated by superimposed comorbidities common to the elderly such as cardiac, pulmonary, and peripheral artery disease. However, observational and training studies demonstrate significant improvement in peak oxygen consumption in both health and disease settings. In addition, exercise training exerts beneficial effects on blood pressure, lipids, glucose tolerance, bone density, depression, and quality of life. A major challenge to physicians and society is to increase the low participation rates of older adults in both home-based exercise and supervised exercise rehabilitation programs.