ABSTRACT
F or the human organism to meet the demands of exercise that may increase the metabolic rate by as much as twentyfold requires coordination of many physiological systems. It would be futile for the lungs to operate at maximum capacity if the heart did not cooperate by pumping blood at a rate necessary to move the blood gases and nutrients needed by the muscle tissues involved. In fact, most of the systems of the body become involved in the adjustments necessary to support all-out athletic efforts. Obviously, the various physiological systems must be properly coordinated to bring about the appropriate responses to the imposed demand.
