EFFECT OF PHYSICAL-TRAINING ON EXERCISE CAPACITY AND GAS-EXCHANGE IN PATIENTS WITH CHRONIC HEART-FAILURE

Decreased exercise capacity is the main factor restricting the daily l ife of patients with chronic congestive heart failure (CHF). We perfor med a controlled, randomized study to evaluate the effect of dynamic e xercise training of moderate intensity on exercise capacity and gas ex change in patients with CHF. Twenty-seven patients with stable CHF, Ne w York Heart Association (NYHA) functional class II and III, were rand omized to training (n=12) and control (n=15) groups, During a 3-month period, the training group underwent a supervised physical training pr ogram using a bicycle ergometer for 30 min 3 times a week at a load co rresponding to 50 to 60% of their peak oxygen consumption, Thereafter, they were advised to continue training at home for the next 3 months. The control group did not change their previous physical activity. A graded maximal exercise test with respiratory gas analysis and an endu rance test with constant submaximal workload were performed at baselin e and after 3 and 6 months. The exercise endurance increased from 14.7 +/-2.0 to 27.8+/-2.7 min (p<0.01) and the peak oxygen consumption tend ed to improve from 19.3+/-1.6 to 21.7+/-2.3 mL/kg/min (p=0.09) during the supervised training period. At submaximal workloads, minute ventil ation was reduced by 16% per se (p<0.01) and by 7% in proportion to ca rbon dioxide production (p<0.05). Oxygen consumption at the anaerobic threshold increased from 10.5+/-0.8 to 12.7+/-1.0 mL/kg/min (p<0.05). The positive training effects were associated with an improvement in t he NYHA functional class. The effects of supervised training were pres erved during the home-based training period. The results indicate that physical training of moderate intensity significantly improves the ex ercise capacity and reduces the exaggerated ventilatory response to ex ercise, particularly at submaximal working levels in patients with CHF . This is associated with alleviation of symptoms.