The physiology behind exercise testing

Despite significant advances in related technologies, the exercise test remains a useful clinical tool. It can define the limits of performance in an athlete or the functional capabilities of the patient with heart disease. Although virtually all of the body's physiologic and metabolic systems interact in a coordinated fashion to perform a single bout of exhaustive exercise, a major burden falls on the cardiopulmonary system. A good understanding of the basic physiologic responses to acute exercise can assist the clinician in applying the information gained from the test. These responses are influenced by state of health and fitness, age, gender, type of exercise, exercise position, and the environment. This article provides an overview of the physiologic responses to acute exercise, and discusses the many factors that influence these responses.