The short- and long-term outcome of exercise reconditioning on exercise tolerance and breathlessness scores were evaluated in a group of patients with severe chronic obstructive pulmonary disease (COPD). After a combined initial program of eight weeks, the patients were randomized into two groups: group A followed a supervised training program for another 12 weeks; group B was discharged after this initial program and received written instructions to continue exercise training at home. The patients were evaluated at the start, after the initial eight weeks' training, after six months, and after one year. For the total group, exercise tolerance, assessed by 12-minute walking distance, increased significantly from 784m to 848m (p less than .05) after the initial program. Neither breathlessness scores nor spirometric data changed significantly. In group A, the increase in exercise tolerance persisted not only at the end of the continued training program but even at the end of the one-year follow-up. In group B, there was a progressive and significant decline of exercise tolerance during the one-year follow-up. Our data confirm that even in severe COPD patients, exercise tolerance can increase significantly without any change in spirometric data and without an increased tolerance for the sensation of dyspnea. A supervised training program must be continued to stabilize the obtained effects because even when an initial improvement is experienced, patients may lack motivation to continue an unsupervised training program.