Background: This small clinical trial tested the hypothesis that the addition of inspiratory muscle training (IMT) to aerobic exercise training (AE) results in further improvement in cardiorespiratory responses to exercise than those obtained with AE in patients with chronic heart failure (CHF) and inspiratory muscle weakness (IMW).
Methods: Twenty-four patients with CHF and IMW (maximal inspiratory pressure <70% of predicted) were randomly assigned to a 12-week program of AE plus IMT (AE + IMT, n = 12) or to AE alone (AE, n = 12). Before and after intervention, the following measures were obtained: maximal inspiratory muscle pressure (PI(max)), peak oxygen uptake (Vo(2)peak), peak circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, oxygen uptake kinetics during recovery (T(1/2)Vo(2)), 6-minute walk test distance, and quality of life scores.
Results: Compared to AE, AE + IMT resulted in additional significant improvement in PI(max) (110% vs 72%), Vo(2)peak (40% vs 21%), circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, and T(1/2)Vo(2). Six-minute walk distance and quality of life scores improved similarly in the 2 groups.
Conclusion: This randomized trial demonstrates that the addition of IMT to AE results in improvement in cardiorespiratory responses to exercise in selected patients with CHF and IMW. The clinical significance of these findings should be addressed by larger randomized trials.
Trial registration: ClinicalTrials.gov NCT00634296.