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Exercise and heart failure: A statement from the American Heart Association Committee on exercise, rehabilitation, and prevention.

Heart failure (HF) may be defined as the inability of the heart to meet the demands of the tissues, which results in symptoms of fatigue or dyspnea on exertion progressing to dyspnea at rest. The inability to perform exercise without discomfort may be one of the first symptoms experienced by patients with HF and is often the principal reason for seeking medical care. Therefore, exercise intolerance is inextricably linked to the diagnosis of HF. It might be expected that a tight relationship would exist between indices of resting ventricular function and exercise capacity. Data indicate, however, that indices of resting ventricular function (such as ejection fraction [EF]) are only weakly correlated to exercise tolerance.1

Exercise intolerance is defined as the reduced ability to perform activities that involve dynamic movement of large skeletal muscles because of symptoms of dyspnea or fatigue. Many investigators have sought mechanisms to explain the source of exercise intolerance. The aims of this position statement are to review (1) factors that affect exercise tolerance, with specific emphasis on chronic HF due to systolic dysfunction; (2) data that support the role of exercise training in chronic systolic HF, including the risks and benefits; (3) data on exercise training in patients with HF due to diastolic dysfunction; and finally (4) the subgroups of patients with HF for which data are lacking, and (5) the subgroups of patients who should not be included in exercise training programs. We anticipate this report will stimulate appropriate use of exercise training in patients with HF when indicated and encourage further studies in those areas in which data are lacking.

### Cardiovascular

The capacity for performing aerobic exercise depends on the ability of the heart to augment its output to the exercising muscles and the ability of these muscles to utilize oxygen from the delivered …