Efficacy of High-Intensity Exercise Training on Left Ventricular Ejection Fraction in Men With Coronary Artery Disease (the Training Level Comparison Study)

Abstract

Efficacy of High-Intensity Exercise Training on Left Ventricular Ejection Fraction in Men With Coronary Artery Disease (the Training Level Comparison Study); Oberman A, Fletcher GF, Lee J, Nanda N, Fletcher BJ, Jensen B, Caldwell ES; Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama; Am J Cardiol 1995;76:643-647 Background. Effects of training on myocardial performance in patients with depressed left ventricular function remain unclear. Methods. Men with coronary artery disease, aged 30 to 70 years, were randomized to exercise training of either low intensity (50% ˙VO2max, n = 89), or high intensity (85% ˙VO2max, n = 111). Results. Both groups significantly increased exercise capacity without adverse events, but the increase was greater in the high-intensity group. The mean rest-peak exercise change in left ventricular ejection fraction (LVEF) in the high-intensity group rose from 6.20% at baseline to 6.54% at 6 months and to 6.73% at 12 months, whereas the low-intensity group showed no improvement at 6 months and a decrease at 12 months. When the groups were subdivided by baseline LVEF <50% vs. >50%, those with the higher LVEF in the high-intensity group showed a greater (P =.05) increase in the rest-peak LVEF from baseline to 1 year. Conclusion. High-intensity training, compared with low-intensity training, showed more improvement in the rest-peak LVEF, especially in those with a higher LVEF at baseline, and a greater increase in exercise capacity. Comment. This study demonstrates that relatively higher intensity exercise training, among patients in whom it can be performed safely, results in greater improvements in exercise capacity than low-intensity training. Several findings in regard to left ventricular function are noteworthy from this study: (1) resting LVEF did not change in either group; (2) the changes in left ventricular functional reserve (rest-peak ejection fraction) were small, but may be clinically significant; (3) they were observed only in the high-intensity group; and (4) the mechanism for such improvements remains unclear.