[Effect of specific inspiratory muscle training on dyspnea and exercise tolerance in congestive heart failure]

It has been shown that the inspiratory muscles of patients with congestive heart failure (CHF) are weaker than normal. This weakness may contribute to dyspnea and limit exercise capacity. But respiratory muscles can be trained for increase in both strength and endurance. This study was designed to evaluate the effect of specific inspiratory muscle training (SIMT) on muscular performance, lung function, dyspnea and exercise capacity in moderate heart failure. 10 patients with CHF (NYHA functional class II-III) received 1/2 hour of SIMT daily, 6 times/week, for 3 months. They started breathing at a resistance 15% of their Pimax for 1 week and the resistance was then increased incrementally to 60%. Spirometry, inspiratory muscle strength and endurance, and the 12-minute walk test were performed before and after the training period. All showed an increase in inspiratory muscle strength and endurance. This was associated with a small but significant increase in FVC, a significant increase in the distance walked (458 +/- 29 to 562 +/- 32 m, p < 0.01), and improvement in the dyspnea index score. SIMT resulted in increased inspiratory muscle strength and endurance. This increase was associated with decreased dyspnea and an increase in submaximal exercise capacity. SIMT may prove to be useful complementary therapy in CHF.