Additional physical activity during cardiac rehabilitation leads to an improved heart rate recovery in male patients after coronary artery bypass grafting

Background Heart rate recovery (HRR) after exercise, which is thought to be a marker of vagal activity, has been reported to improve after cardiac rehabilitation (CR) with exercise in patients with coronary heart disease. The aim of this study was to determine whether or not additional physical activity outside the CR program, would accelerate improvement of the HRR in male patients after coronary artery bypass grafting (CABG). Methods and Results Twenty male patients were enrolled in a supervised CR program at 2 weeks after CABG, and divided into an active group (walking greater than or equal to5,434steps/day) or a less-active group. The time constant of HRR immediately measured after pedaling exercise was assessed at baseline and after the 2-week CR program. After completion of the CR program, the time constant of HRR improved from 439.7 +/- 177 s to 288.6 +/- 97.4 s in the active group (p<0.01), but no changes were observed in the less-active group. Conclusions The results suggest that additional physical activity during a CR program may lead to an improved HRR in patients after CABG. Therefore, post-CABG patients should increase their level of physical activity in addition to that in the CR to improve their cardiac autonomic control.