Exercise-based cardiac rehabilitation is currently underused, even though exercise is one of the few nonsurgical interventions that can make heart disease patients feel better physically and mentally. Benefits include increased muscle strength, lowered heart rate, increased stroke volume, and increased submaximal and maximal working capacity. Patients in cardiac rehabilitation programs, however, often do not exercise enough to obtain maximal benefit. Programs should ideally be initiated under supervision to provide the correct regimen and requisite vigorous activity. Subsequent moderate exercise regimens can be done at home. All patients should engage in lifelong maintenance programs.