The purpose of this study was to evaluate the efficacy of a unique program of ventilation-feedback training combined with leg-cycle exercise to improve exertional endurance and decrease perceived dyspnea in patients with chronic obstructive pulmonary disease (COPD). Thirty-nine patients (67.5 +/- 8.1 yr of age) with moderate to severe COPD (42.6% of predicted forced expiratory volume in 1 s) were randomized to one of three 6-week experimental interventions: ventilation-feedback with exercise (V(+EX)), exercise only (EX(ONLY)), or ventilation-feedback only (VF(ONLY)). At baseline and at 6 weeks, patients completed a constant work-rate leg-cycle ergometer test at 85 percent of maximal power output. There were increases within the groups in exercise duration: 11.5 min (103%), 8.0 min (66%), and 0.4 min (4%) for the VF(+EX), EX(ONLY) and VF(ONLY) groups, respectively. The VF(ONLY) group experienced no significant within-group changes in selected gas exchange parameters. However, there were significant (p < 0.05) posttraining changes in minute ventilation, tidal volume, breathing frequency (f), and expiratory time (Te) in the VF(+EX) group, and in f and Te in the EX(ONLY) group. After completing the training, VF(+EX) and EX(ONLY) patients reported less breathlessness and perceived exertion (p < 0.05). The VF(ONLY) patients' ratings changed in the hypothesized direction but were not significant. Based on these preliminary data, VF(+EX) and EX(ONLY) were equally effective in improving leg-cycle exercise tolerance in patients with moderate to severe COPD.