Aerobic group training improves exercise capacity and heart rate variability in elderly patients with a recent coronary event. A randomized controlled study.

ABSTRACT

AIMS: Reduced heart rate variability is associated with an unfavourable prognosis in patients with ischaemic heart disease. Whether physical training can modify this risk factor is not definitely proven. Our hypothesis was that training might increase both physical capacity and heart rate variability in elderly patients recovering from an acute coronary event, i.e. acute myocardial infarction (n=38) or an episode of unstable angina (n=27). METHODS AND RESULTS: 24 h ambulatory ECG recordings were obtained from 65 patients randomized to either a 3 months supervised outpatient group training programme 50 min three times a week (n=29) or to a control group (n=36). The two groups were well balanced as regards demographic data and pharmacological treatment at the time of randomization. Body mass index and pharmacological therapy remained unchanged during the study. Heart rate variability was analysed in the time and frequency domains. At the 3 month follow-up, exercise tolerance had increased from 103 to 120 W in the training group (P<0.001), and from 102 to 106 W in the control group (ns). The time-domain heart rate variability measures SDNN (standard deviation of all filtered RR intervals over the analysed time period) and SDANN (standard deviation of the means of all filtered RR intervals for all 5 min epochs of the analysed time period) increased significantly during the daytime in the training group (P<0.01 and P<0.05, respectively), but not in the control group. A significant improvement in night-time heart rate variability was observed among controls. There was a statistically significant correlation (P<0.05) between changes in 24 h overall power (frequency domain measure) and changes in maximal exercise capacity in the training group. CONCLUSION: A regular aerobic group training programme after an acute coronary event can significantly improve exercise capacity and modify heart rate variability in a prognostically favourable direction in elderly low-to-intermediate risk patients, recovering from an acute coronary event.