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Abstract Introduction Chronic heart failure (CHF) has been characterized with microcirculation and endothelial abnormalities, as well as impaired function of the respiratory system. Exercise training programs have been an important component of CHF rehabilitation. Inspiratory muscle training (IMT), a supplementary form of exercise, induces beneficial effects on the functional status of patients; however, there have not been much data on its effects on the systemic microcirculation. Purpose The aim of the study was to evaluate the effect of the addition of an IMT regime to a combined exercise rehabilitation program on the microcirculation of non-exercising muscles (systemic effect) in CHF patients. Method Twenty-five (22♂/3♀) stable CHF patients, on optimal medication, age: 60.3±8.9 years, ejection fraction (EF): 32.3±7.7%, maximal inspiratory muscle pressure (MIP): 81.9±23.8 cmH2O, predicted MIP (%): 89.1±25.6, VO2peak:17.9±3.9 ml/kg/min, NYHA≥ΙΙ were randomly assigned to the intervention group (IG, n=12) or the control group (CG, n=13) and trained 3×/week for 12 weeks. Both groups participated in a combined regime (aerobic exercise and muscle training). In addition, IG performed IMT (5 sets × 10 repetitions, 35-60% MIP) and CG sham-IMT (5 sets × 10 repetitions, 10% MIP). Systemic microcirculation was assessed with near-infrared spectroscopy (NIRS) and the 3-min vascular occlusion technique at the thenar muscle. Cardiorespiratory exercise testing and muscle strength assessment were also performed, before and after the program. Microcirculation variables evaluated included oxygen consumption rate and reperfusion rate. Values are expressed as mean and standard deviation. Results Reperfusion rate improved in the IG compared to the CG (from 3.5±1.6 to 4.5±1.4 %/min vs 3.2±1.6 to 3.2±1.8 %/min, p0.05), while oxygen consumption rate did not change (IG: from 12.9±3.6 to 14.1±2.9 %/min, CG: 12.4±4.8 to 12.9±5.5 %/min, p0.05). There was a significant between-group difference for MIP (IG: from 74±29 to 98±21 cmH2O, CG: from 90±16 to 91±16 cmH2O, p0.05). Not any between-group differences (p0.05) were found for VO2peak (IG: from 18.2±3.7 to 19.2±4.3 ml/kg/min, CG: from 17.6±4.1 to 18.5±4.7 ml/kg/min), maximum workload (IG: from 120±52 to 132±49 watt, CG: from 119±43 to 129±45 watt), maximum leg extension load (IG: from 42±14 to 48±14 kg, CG: from 42±16 to 47±18 kg), or any other cardiorespiratory and strength variables evaluated. Conclusions An IMT regime, in addition to a combined exercise training rehabilitation program, improved the systemic microcirculation in CHF patients; in particular, the reperfusion rate index, which reflects the endothelial function.
Katsoula et al. (Sat,) studied this question.