The earliest reports of training patients with significant left ventricular impairment were case reports or small series. The first report of exercise training of patients with heart failure was in 1987, in Russia [11
]. This study compared the effects of exercise training with no exercise in post-myocardial infarction patients who showed clinical signs of heart failure. The training continued for 11 months and included exercise therapy, cycle ergometry and walking. The patients who exercised showed a considerable increase in physical working capacity, a more favorable hemodynamic response to stress, a higher stroke index, a reduced heart rate increment and a greater reduction in systemic peripheral resistance compared with the control patients.
Further physiological investigation of the training-induced improvements in exercise capacity was undertaken by Sullivan and colleagues [8
]. This was closely followed in the early 1990s by the first randomized controlled trials of training in patients with chronic stable heart failure [10
], which showed an increase in exercise capacity and improved symptomatic status.
In the rest of the 1990s, an increasing number of larger and better designed studies in patients with heart failure demonstrated a consistent increase in exercise capacity and a bewildering array of physiological benefits with exercise training. A summary of trials performed by a collaborative European group [13
] and an overview of all trials published up to 1998 [14
] have shown a consistent 15–20% increase in exercise capacity in a broad range of patients with heart failure. The beneficial effects of training have included improvements in hemodynamic responses, myocardial perfusion, diastolic function, skeletal muscle function and histological and biochemical responses, ventilatory control, peripheral vascular and endothelial function and neurohormonal and autonomic function.
Global exercise capacity was improved even with only low intensity training by relatively small muscle groups, which shows the primary importance of peripheral training mechanisms in even severe heart failure [15
]. Although the majority of these training effects are likely to be beneficial for a patient with CHF, none of the trials to date has been designed specifically to address the question of prognosis or alteration in disease progression. The largest reported controlled trial [16
] included almost 100 patients and showed a statistically significant improvement in survival and a statistically significant reduction in hospital readmissions for heart failure. The results of this study, however, must be regarded as an exciting possibility of benefit rather than proof. A sufficiently powered trial is required to evaluate the proposal that training may improve survival.