Respiratory muscle endurance training in chronic obstructive pulmonary disease - Impact on exercise capacity, dyspnea, and quality of life

Inspiratory muscle training may have beneficial effects in certain patients with chronic obstructive pulmonary disease (COPD). Because of the lack of a home training device, normocapnic hyperpnea has rarely been used as a tra ining mode for patients with COPD, and is generally considered unsuitable t o large-scale application. To study the effects of hyperpnea training, we r andomized 30 patients with COPD and ventilatory limitation to respiratory m uscle training (RMT; n = 15) with a new portable device or to breathing exe rcises with an incentive spirometer (controls; n = 15). Both groups trained twice daily for 15 min for 5 d per week for 8 wk. Training-induced changes were significantly greater in the RMT than in the control group for the fo llowing variables: respiratory muscle endurance measured through sustained ventilation (+825 +/- 170 s [mean +/- SEM] versus -27 +/- 61 s, p < 0.001), inspiratory muscle endurance measured through incremental inspiratory thre shold loading (+58 +/- 10 g versus +21.7 +/-: 9.5 g, p = 0.016), maximal ex piratory pressure (+20 +/- 7 cm H2O versus -6 +/- 6 cm H2O, p = 0.009), 6-m in walking distance (+58 +/- 11 m versus +11 +/- 11 m, p = 0.002), (V) over dot O-2peak (+2.5 +/- 0.6 ml/kg/min versus -0.3 +/- 0.9 ml/kg/min, p = 0.0 15), and the SF-12 physical component score (+9.9 +/- 2.7 versus +1.8 +/- 2 .4, p = 0.03). Changes in dyspnea, maximal inspiratory pressure, treadmill endurance, and the SF-12 mental component score did not differ significantl y between the RMT and control groups. In conclusion, home-based respiratory muscle endurance training with the new device used in this study is feasib le and has beneficial effects in subjects with COPD and ventilatory limitat ion.