Breathing exercises over four to 15 weeks improve functional exercise capacity in people with COPD compared to no intervention; however, there are no consistent effects on dyspnoea or health-related quality of life. Outcomes were similar across all the breathing exercises examined. Treatment effects for patient-reported outcomes may have been overestimated owing to lack of blinding. Breathing exercises may be useful to improve exercise tolerance in selected individuals with COPD who are unable to undertake exercise training; however, these data do not suggest a widespread role for breathing exercises in the comprehensive management of people with COPD.
Can ventilation-feedback training augment exercise tolerance in patients with chronic obstructive pulmonary disease?
Exercise-induced dynamic hyperinflation contributes to decreased exercise tolerance in chronic obstructive pulmonary disease (COPD). It is unknown whether respiratory retraining (ventilation-feedback [VF] training) can affect exercise-induced dynamic hyperinflation and increase exercise tolerance. Objectives: To determine whether patients with COPD would achieve longer exercise duration if randomized to a combination of exercise training plus VF training than either form of training on its own.
                A total of 64 patients randomized to 1 of 3 groups: VF plus exercise (n = 22), exercise alone (n = 20), and VF alone (n = 22).
                Exercise duration before and after 36 training sessions and exercise-induced dynamic hyperinflation and respiratory pattern before and after training were measured. In the 49 patients who completed training, duration of constant work-rate exercise was 40.0 (+/- 20.4) minutes (mean +/- SD) with VF plus exercise, 31.5 (+/- 17.3) minutes with exercise alone, and 16.1 (+/- 19.3) minutes with VF alone. Exercise duration was longer in VF plus exercise than in VF alone (P < 0.0001), but did not reach predetermined statistical significance when VF plus exercise was compared with exercise alone (P = 0.022) (because of multiple comparisons, P </= 0.0167 was used for statistical significance). After training, exercise-induced dynamic hyperinflation, measured at isotime, in VF plus exercise was less than in exercise alone (P = 0.014 for between-group changes) and less than in VF alone (P = 0.019 for between-group changes). After training, expiratory time was longer in VF plus exercise training (P < 0.001), and it was not significantly changed in the other two groups.
                The combination of VF plus exercise training decreases exercise-induced dynamic hyperinflation and increases exercise duration more than VF alone. An additive effect to exercise training from VF was not demonstrated by predetermined statistical criteria.