BACKGROUND: Exercise training is an important component of pulmonary rehabilitation, but it remains questionable how training intensity affects patient-centered outcomes. The aim of this study was to compare the effects of 2 aerobic training intensities on health-related quality of life (HRQOL), symptom control, and exercise tolerance in subjects with COPD. METHODS: Thirtyfour subjects with mild to very severe COPD participated in an equivalence/non-inferiority randomized controlled trial with a parallel group blinded to 60 or 80% maximum work rate (W max ) aerobic training intensity. The intervention was an out-patient pulmonary rehabilitation program conducted 3 times/week for 8 weeks. Outcomes were assessed with the St George Respiratory Questionnaire (primary outcome), Mahler's dyspnea index, London Chest Activity of Daily Living scale, 6-min walk test, and constant-load and incremental exercise tests. RESULTS: Subjects were randomly allocated to aerobic training intensity of 60% W max (group 1, n ‫؍‬ 17) or 80% W max (group 2, n ‫؍‬ 17). Although there were significant improvements in all outcomes for both groups, there were no between-group differences in mean change in the St George Respiratory Questionnaire (P ‫؍‬ .31, 95% CI ؊12.0 to 3.9), Mahler's dyspnea index (P ‫؍‬ .38), London Chest Activity of Daily Living scale (P ‫؍‬ .92), 6-min walk test (P ‫؍‬ .50, 95% CI 6.2-71.1), constant-load exercise test (P ‫؍‬ .50), and incremental exercise test (P ‫؍‬ .12). There was only one exercise-related adverse event of cardiac symptoms. CONCLUSIONS: Aerobic training intensity of at least 60% W max has a positive impact on COPD patient-centered outcomes, with no additional benefit of increasing intensity to 80% W max in HRQOL, symptom control, and exercise tolerance, challenging the present clinical attitude of rehabilitation professionals. (ClinicalTrials.gov registration NCT01944072.)

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PR was associated with improvements in all comorbid subgroups of patients, underlining the important role of exercise training in rehabilitation of those chronic diseases associated with COPD. On the other hand, the presence of comorbidities in COPD patients, if clinically controlled, should not preclude access to PR.