The incidence and prevalence of heart failure increase with age. The cardinal manifestation of heart failure is exercise intolerance. The cardiopulmonary exercise test with determination of peak VO(2) provides an integrated measure of both central and peripheral abnormalities in heart failure. It is used to predict prognosis, identify patients for cardiac transplantation and to distinguish cardiac from pulmonary causes of unexplained dyspnea. Most data is derived from middle-aged patients with moderate to severe systolic heart failure. Many elderly patients suffer from diastolic heart failure and the value of cardiopulmonary exercise testing in diastolic heart failure and in the elderly has not been well studied. This review examines the physiology of aging and the clinical utility of exercise testing in elderly patients with heart failure.