This speech begins with the presentation of a conceptual scheme of the physical working capacity of a person starting a training program. The scheme shows that after exercise, when recovery begins and sufficient time elapses, the individual recovers and adapts to a level of physical working capacity which is higher than his starting level. From this scheme it is shown that a light workout produces faster recovery but a lesser degree of adaptation to a higher level; a strenuous workout that allows insufficient time for recovery before exercising again might impair the individual's physical working capacity. For an exercise session for cardiopulmonary conditioning for deconditioned or pathological adults, the following is recommended: a warmup, a stimulus period, and a cool-down composed for the most part of aerobic exercises (exercises which utilize energy which is liberated mainly through aerobic rather than anaerobic pathways). It is stated that during the stimulus period the individual should moderate his heart rate so that his heart stays within the "target zone"; the use of the heart rate in this manner provides a built-in barometer of relative exercise stress that is independent of the person's fitness level and requires the individual to perform a higher intensity of work to achieve his heart rate as his fitness improves. Charts and diagrams are referred to in the text and appear as appendixes. (JA)