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
Thirty-four 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.).