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

Aims Reduced heart rate variability is associated with an unfavourable prog nosis in patients with ischaemic heart disease. Whether physical training c an modify this risk factor is not definitely proven. Our hypothesis was tha t training might increase both physical capacity and heart rate variability in elderly patients recovering from an acute coronary event, i.e. acute my ocardial 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 progra mme 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 t reatment at the time of randomization. Body mass index and pharmacological therapy remained unchanged during the study. Heart rate variability was ana lysed 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 rat e variability measures SDNN (standard deviation of all filtered RR interval s 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 per iod) 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 i mprovement in night-time heart rate variability was observed among controls . There was a statistically significant correlation (P<0.05) between change s in 24 h overall power (frequency domain measure) and changes in maximal e xercise 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 fav ourable direction in elderly low-to-intermediate risk patients, recovering from an acute coronary event. (C) 1999 The European Society of Cardiology.