Effects of Physical Training on the Recovery of the Autonomic Nervous Activity During Exercise After Coronary Artery Bypass Grafting

- Effects of Physical Training After CABG -

Abstract

Analysis of heart rate variability (HRV) can identify patients at risk of sudden cardiac death after myocardial infarction. The present study examined the effect of 2 weeks of supervised aerobic exercise training on the recovery of the autonomic nervous activity, exercise capacity, and cardiac output (CO) after coronary artery bypass grafting (CABG). Twenty-eight patients were randomly divided into the training group or the control group and performed exercise tests at 1 week, 3 weeks, 3 months, 6 months and 1 year after CABG. The HRV was measured, and the high-frequency component of HRV was used as an index of parasympathetic nerve activity (PNA); the plasma norepinephrine concentration (NE) was used as an index of sympathetic nervous activity. Cardiac output was also measured. In the training group, peak VO₂, peak CO and PNA during exercise had improved at 3 weeks, but there was no improvement in these indices in the control group. NE decreased 1 week after CABG in both groups. These results indicate that physical training soon after CABG improves not only the exercise capacity, but also PNA.