Background: Patients with heart failure (HF) are characterized by several skeletal muscle abnormalities that are closely related to their exercise intolerance. Aim of this study was to investigate the effects of three different interval exercise training programs on skeletal muscle fiber-type distribution and aerobic capacity of HF patients. Method and Material: The study consisted of 10 HF patients that participated in a rehabilitation program 3 times per week, for a total of 36 sessions. Patients performed cardiopulmonary exercise test (CPET) and percutaneous needle biopsy of the vastus lateralis muscle before and after the completion of the program. Histological measurements included the fiber type distribution and cross section area (CSA) of skeletal muscle fiber. Main CPET measurements included oxygen uptake at peak (VO2p), at anaerobic threshold (AT), peak work (WRp) and the slope of ventilatory equivalent for carbon dioxide output (VE/VCO2slope). Results: After the exercise training program there was a significant increase in the CSA of type I (4509±1184 to 4862±1154 μm2, p<0.001) and type II (from 4408±1166 to 4937±1160 μm2, p<0.001) fibers. The proportion of aerobic type I fibers increased significantly from 43±11 to 51±6% (p=0.05). The percentage change of type I CSA was significantly correlated with the percentage change of WRp (r=0.814, p=0.004). WRp, VO2p, AT increased significantly (108±36 to 129±49 watts, p=0.008; 17.7±4.2 to 19.7±4.6 ml/kg/min, p=0.024; 12.0±3.3 to 13.5±4.1 ml/kg/min, p=0.05, respectively) and VE/VCO2slope decreased (35.1±8.0 to 31.3±5.7, p=0.045). Conclusions: The results indicate that interval exercise training might have an anabolic effect by increasing the CSA of muscle fibers and could improve aerobic capacity probably by inducing a reshift of fiber type distribution in HF patients.
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Health Science Journal
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Medical and Health Sciences ▶ Health Sciences Nursing
(EN)
