Inspiratory muscle training using an incremental endurance test alleviates dyspnea and improves functional status in patients with chronic heart failure

Background The benefits of inspiratory muscle training (IMT) in patients with chronic heart failure (CHF) have been inadequately studied. Design and Methods Using a prospective, age and sex-matched controlled study, we investigated 35 patients with moderate to severe CHF (NYHA class II-III and left ventricular ejection fraction 24.4 +/- 1.3% [mean +/- SEM]). An incremental respiratory endurance test using a fixed respiratory workload was provided by software with an electronic mouth pressure manometer interfaced with a computer. The training group (n=20) exercised at 60% of individual sustained maximal inspiratory pressure (SMIP) and the control group (n=15) at 15% of SMIP. All patients exercised three times weekly for 10 weeks. Pulmonary function, exercise capacity, dyspnea and quality of life were assessed, pre- and post-training. Results The training group significantly increased both maximum inspiratory pressure (Pimax), (111 +/- 6.8 versus 83 +/- 5.7cmH(2)O, P