Acute effects of inspiratory muscle training on microcirculation in chronic heart failure patients

Abstract Introduction Patients with chronic heart failure (CHF) have been presented with microcirculation alterations and vascular endothelial dysfunction. Exercise training programs, including inspiratory muscle training (IMT) as an alternative/additional means of exercise, have been shown to improve the functional status of these patients. However, there has not been much data on the acute effect of IMT on systemic microcirculation. Purpose The aim of this study was to investigate the acute effect of an IMT session on the microcirculation of non-exercising muscles (systemic effect) in CHF patients. Method Thirty-four (30♂/4♀) stable CHF patients [age: 61±9 years, EF: 34±8%, VO2peak: 17.5±4.0 ml/kg/min, NYHA class ≥II) participated in a single IMT session (5 sets/10 repetitions at 60% of maximum inspiratory pressure). Systemic microcirculation was assessed with near-infrared spectroscopy (NIRS) and the 3-min vascular occlusion technique at the thenar muscle, before and after the session. Variables evaluated were the basal tissue oxygen saturation (StO2), the oxygen consumption rate and the reperfusion rate. Values are in mean and standard deviation. Results After the IMT session, the reperfusion rate was increased (from 3.4±1.6 to 3.9±1.7 %/min, p=0.007). The oxygen consumption rate was also increased (from 12.7±3.8 to 13.2±3.9 %/min, p=0.021). Finally, the basal tissue oxygen saturation values tended to increase (from 85.5±6.4. to 84.7±6.2%, p=0.065), an alteration of not any clinical significance. Conclusions An IMT session had a beneficial effect on the systemic microcirculation of CHF patients, particularly on the reperfusion rate which reflects endothelial function.