Exercise, functional aerobic capacity, and aging--another viewpoint.

Currently, there is strong public interest in exercise conditioning, especially endurance types of dynamic exercise. In addition to the short-term benefits of enhanced fitness and health, there is a growing expectation of long-term benefits in relation to possible reduction of morbidity, disability, and mortality from chronic disease, especially cardiovascular disease. Physical exercise increases aerobic metabolism and the associated pulmonary and cardiovascular responses needed to deliver the required oxygen. Functional aerobic capacity or maximal oxygen consumption (VO2max) defines the functional limits of the cardiovascular system. Aerobic capacity can be measured or be reasonably estimated by appropriate methods of exercise testing, and is probably the best integrated measure of the functional limits of the whole body which can define the effects of the aging process. The rate of decline in VO2max observed in longitudinal studies of the same subjects substantially exceeds that observed in cross-sectional studies sampling male subjects of different ages. This rate is twice as great in sedentary as in physically active male subjects. When these provocative findings are considered in relation to trends observed in survival of populations vs the nearly constant limit of the average life span, the need for appropriately designed long-term prospective, definitive studies becomes apparent.