Interval exercise training improves tissue oxygenation in patients with chronic heart failure

Abstract

Aim: Aim of our study was to evaluate the effects of interval exercise training (IT) programs, regarding whole body oxygen uptake and peripheral tissue oxy-genation, in Chronic Heart Failure (CHF) patients during recovery. Methods: Twenty-six CHF patients (21 males/5 females), mean age of 49 ± 12 years, par-ticipated in the study. Fifteen patients were assigned to IT and 11 patients were assigned to IT followed by strength training. All patients were trained for 40 minutes per session, 3 times per week, for 12 weeks. They performed a symptom-limited cardiopulmonary exercise testing (CPET), before and after the comple-tion of the program. Muscle tissue oxygen saturation (StO 2) of quadriceps femoris was continuously meas-ured by Near Infrared Spectroscopy (NIRS) during CPET and during the recovery period after the end of exercise. Results: No differences were noted between the two patient groups regarding whole body and pe-ripheral tissue oxygenation indices and, therefore, data from all patients were pooled. After training, an increase in peak oxygen uptake (17 ± 4.5 to 19 ± 5.5 ml/kg/min, p < 0.05), gas exchange threshold (11 ± 3.5 to 12.5 ± 3.5 ml/kg/min, p < 0.05), peak work rate achieved (105 ± 29 to 124 ± 37 Watt, p < 0.05) and the first degree slope of VO 2 at the first minute of recov-ery (0.45 ± 0.2 to 0.61 ± 0.3 L/min 2 , p < 0.05), was noted. In addition, tissue re-oxygenation time con-stant was decreased (65 ± 25 to 52 ± 28 sec, p < 0.001). Conclusion: In conclusion, interval exercise training accelerates oxygen uptake and peripheral tissue oxy-genation during recovery from exercise in CHF pa-tients.