The effects of low-volume high-intensity interval versus moderate intensity continuous training on heart rate variability, and hemodynamic and echocardiography indices in men after coronary artery bypass grafting: A randomized clinical trial study

BACKGROUND: Heart rate variability (HRV) declines after coronary artery bypass grafting (CABG). The purpose of this study was to evaluate the effect of low-volume high-intensity interval training (LV-HIIT) and moderate-intensity continuous training (MICT) on HRV as well as, hemodynamic and echocardiography indices.METHODS: Forty-two men after CABG (۵۵.۱۲ ± ۳.۹۷ years) were randomly assigned into LV-HIIT, MICT, and control (CTL) groups. The exercise training in LV-HIIT consisted of ۲-minute interval at ۸۵-۹۵ percent of maximal heart rate (HRmax), ۲-minute interval at ۵۰% of HRmax and ۴۰-minute interval at ۷۰% of HRmax in MICT for three sessions in a week, for ۶-weeks. HRV parameters were evaluated by ۲۴-hour Holter electrocardiography (ECG) recording, and echocardiography parameters at baseline and end of intervention were measured in all ۳ groups.RESULTS: At the end of the intervention, left ventricular ejection fraction (LVEF) significantly increased in LV-HIIT group (۵۸.۵۳ ± ۷.۲۶ percent) compared with MICT (۵۲.۲۶ ± ۷.۹۱ percent) and CTL (۴۹.۶۸ ± ۷.۲۷ percent) groups (P < ۰.۰۰۱). Furthermore, mean R-R interval, root mean square successive difference (RMSSD) of R-R interval, and standard deviation of R-R interval (SDRR) in LV-HIIT group considerably increased compared with MICT group (P < ۰.۰۰۱). High-frequency power (HF) significantly increased in LV-HIIT and MICT groups compared with CTL group (P < ۰.۰۰۱). On the other hand, low frequency (LF) and LF/HF ratio significantly decreased in LV-HIIT group in comparison with MICT group (P < ۰.۰۱۰).CONCLUSION: These results suggest that LV-HIIT has a greater effect on improvement of cardiac autonomic activities by increasing R-R interval, SDRR, RMSSD, and HF, and decreasing LF and LF/HF ratio in patients after CABG.

کلیدواژه ها:

High-Intensity Interval Trainin ، Continuous Training ، Cardiac Rehabilitation ، Cardiac Autonomic Activity