The main symptoms of chronic heart failure are dyspnoe and exercise intolerance. The pathophysiological basis of these symptoms is not simply the dysfunction of the heart, but a complex interaction of the central circulation, the peripheral vessels, the skeletal muscles, the ventilatory, and the endocrine system. In contrast to acute heart failure, where bedrest is known to be beneficial, prolonged limitation of physical activity can be detrimental in the chronic stage of the disease. Therefore, since the 1980s there have been several reports about heart failure patients participating in exercise programs. The results were encouraging: the physiological gains were impressive, and contrary to prior fears, in the great majority of reports no deterioration of the cardiac function could be observed. The net result of training in this condition is an improvement in exercise capacity in the range of the best pharmacological treatment. In detail, blood flow into the working muscle is increased, the ventilation for each given workload is reduced the skeletal muscle overall function (including biochemical and histological aspects) is improved, the increased neurohormonal activity - especially of the sympathicoadrenergic system - will be normalized, and the patient's quality of life is; significantly improved. Whether all of these beneficial aspects will result in improved survival is not yet proven, although one recent study provides some evidence in this direction. But even if today no definite answer to this question from a large, multicenter trial is available, application of exercise training for selected heart failure patients can be recommended, if adequate supervision is provided.