The sixth edition has been updated to reflect relevant advances in exercise physiology and clinical applications of exercise testing, and the compendium of clinical case examples has been supplemented with contemporary cases from our practices. The premise of the book continues to be that the most important requirement for exercise performance is transport of oxygen to support the bioenergetic processes in the involved muscle cells (including, of course, the heart) and elimination of the carbon dioxide and protons formed as metabolic byproducts. Thus, appropriate cardiovascular and ventilatory responses are required to match those of muscle respiration in meeting the energy demands of exercise.