Inspiratory muscle training in patients with COPD - Effect on dyspnea, exercise performance, and quality of life

Objective: The aim of the study was to assess the effect of target-flow ins piratory muscle training (IMT) on respiratory muscle function, exercise per formance, dyspnea, and health-related quality of life (HRQL) in patients wi th COPD. Patients and methods: Twenty patients with severe COPD were randomly assign ed to a training group (group T) or to a control group (group C) following a double-blind procedure. Patients in group T (n = 10) trained with 60 to 7 0% maximal sustained inspiratory pressure (SIPmax) as a training load, and those in group C (n = 10) received no training. Group T trained at home for 30 min daily, 6 days a week for 6 months. Measurements: The measurements performed included spirometry, SIPmax, inspi ratory muscle strength, and exercise capacity, which included maximal oxyge n uptake ((V)over dotO(2)), and minute ventilation ((V)over dotE). Exercise performance was evaluated by the distance walked in the shuttle walking te st (SWT). Changes in dyspnea and HRQL also were measured. Results: Results showed significant increases in SIPmax, maximal inspirator y pressure, and SWT only in group T (p < 0.003, p < 0.003, and p < 0.001, r espectively), with significant differences after 6 months between the two g roups (p < 0.003, p < 0.003, and p < 0.05, respectively). The levels of (V) over dotO(2) and (V)over dotE did not change in either group. The values fo r transitional dyspnea index and HRQL improved in group T at 6 months in co mparison with group C (p < 0.003 and p < 0.003, respectively). Conclusions: We conclude that targeted IMT relieves dyspnea, increases the capacity to walk, and improves HRQL in COPD patients.