Pulmonary rehabilitation in COPD: Effect of 2 aerobic exercise intensities on subject-centered outcomes—A randomized controlled trial

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 Question-naire (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% Wmax has a positive impact on COPD patient-centered outcomes, with no additional benefit of increasing intensity to 80% Wmax in HRQOL, symptom control, and exercise tolerance, challenging the present clinical attitude of rehabilitation professionals. (ClinicalTrials.gov registration NCT01944072).