Inspiratory Muscle Training Improves Oxygen Uptake Efficiency Slope in Patients With Chronic Heart Failure

PURPOSE: Inspiratory muscle training (IMT) improves exercise capacity and ventilatory responses to exercise in patients with chronic heart failure (CHF) with inspiratory muscle weakness (IMW). We analyzed the effects of IMT on the oxygen uptake efficiency slope (OUES) in this patient population. METHODS: Thirty-two CHF patients with IMW (maximal inspiratory pressure [PImax] < 70% of predicted) were randomly assigned to either a 12-week program of IMT (IMT, n = 16) or placebo-IMT (P-IMT, n = 16). PImax and OUES were obtained before and after the intervention. RESULTS: Inspiratory muscle training resulted in 115% increment in PImax (5.9 +/- 0.9 vs 12.7 +/- 0.9 kPa; P < .001) and in significant improvement in OUES (1,554 +/- 617 to 2,037 +/- 747 mL min O2/L min of minute ventilation; P = .001). There were no significant changes in the P-IMT group. There was a significant association between the changes in PImax and OUES (r = 0.82, P < .01). CONCLUSION: In CHF patients with IMW, IMT results in a significant increase in OUES.