Effects of aerobic exercise on exercise tolerance in patients with chronic heart failure

Abstract

To explore the effects of aerobic exercise on exercise tolerance in patients with chronic heart failure (CHF). A total of 50 CHF patients with left ventricular ejection fraction (LVEF) < 49% by echocardiography were enrolled. And they were randomly divided into exercise group (n = 25) and non-exercise group (n = 25). Cardiopulmonary exercise testing (CPET) was performed. The patients of exercise group underwent an aerobic exercise program in which exercise intensity was decided by anaerobic threshold (AT) before 10 J/s while those of non-exercise group performed daily activities. After 6 sessions of supervised aerobic exercise, the home-based aerobic exercise training began. CPET was re-examined 3 months later. The VO(2) AT, VO(2) peak, Load AT, Load peak, peak VO(2)/HR and VE/VCO(2) slope at baseline were similar between exercise group and non-exercise group (P > 0.05). The VO(2) AT, VO(2) peak, Load AT, Load peak and peak VO(2)/HR in patients of exercise group were increased compared with baseline, The differences between baseline and 3 months later expressed as ΔVO(2) AT, ΔVO(2) peak, ΔLoad AT, ΔLoad peak, Δpeak VO(2)/HR and ΔVE/VCO(2) slope, The differences of ΔVO(2) AT, ΔVO(2) peak, ΔLoad AT, ΔLoad peak and Δpeak VO(2)/HR between two groups were statistically significant [ΔVO(2) AT: 2.8 (1.2 - 3.5) ml×kg(-1)×min(-1) vs -0.3 (-2.8 - 0.1) ml×kg(-1)×min(-1), P < 0.01; ΔVO(2) peak: 3.4 (1.8 - 4.6) ml×kg(-1)×min(-1) vs -0.5 (-1.4 - 0.3) ml×kg(-1)×min(-1), P < 0.01; ΔLoad AT:15.0 (2.5 - 22.5) J/s vs 0.5(-4.2 - 3.8) J/s, P < 0.01; ΔLoad peak: 15.0 (1.3 - 25.0) J/s vs 0.0 (-8.8 - 15.0) J/s, P < 0.05; Δpeak VO(2)/HR: 2.3 (0.0 - 4.0) ml×kg(-1)×beat(-1) vs -0.1 (-0.7 - 1.2) ml×kg(-1)×beat(-1), P < 0.01]. The difference of ΔVE/VCO(2) slope was not statistically significant [-2.3 (-12.2 - 1.8) vs 1.0 (-0.4 - 2.6), P > 0.05]. After 3 months of aerobic exercise, exercise capacity may improve in the CHF patients.