Increasing the benefits of coronary artery surgery: A comparison of the effects of aerobic and power exercise training on aspects of cardiovascular function

Exercise rehabilitation is now widely used in cardiac disease as a means of attaining and even exceeding the pre-morbid functional state and level of physical activity. This is a study of exercise rehabilitation after coronary artery surgery. The main aim was to compare the effects of aerobic exercise training with those of power or strength exercise training on aspects of cardiovascular function. There are few reports on power exercise training in previously untrained cardiac patients. In this study, exercise performance on a treadmill was the primary variable measured. Others were physical changes, arrhythmias, ST segments, haemostatic factors, lipids and lipoproteins, left ventricular function and myocardial perfusion. Effects of the programme that were not assessed include psychological factors, general wellbeing, employment status, dietary and smoking habits. Eighty one men were studied. Their mean age was 56 years (range 35 to 70 years). They were assessed at baseline, three months and six months. After baseline measurements, they were randomised to three groups. The control group (n = 27) had no formal exercise training. The aerobic group (n = 27) had six months' graduated supervised aerobic exercise training. The power group (n = 27) had six months' graduated supervised power (strength) exercise training using circuit weight training. The exercise sessions lasted 12-60 minutes and were held three times a week in a specially equipped gymnasium. They were supervised by a physiotherapist, cardiac rehabilitation sister and a physician. No cardiovascular monitoring took place. All measurements were done at each assessment except Thallium-201 scintigraphy and gated technetium scans which were done at baseline and six months. All results were initially analysed by analysis of variance and Scheffe test. The appropriate test of significance (Student's t-test, Mann-Whitney test or Wilcoxon test) was then employed when indicated. In the aerobic group, there was a clear improvement in treadmill performance after three months (baseline 650.Ss, three months 780.8s, p = 0.004); it was maintained at six months (846.9s, p <0.0001). In the power group, significant improvement was delayed until six months (baseline 784.2s, three months 867.3s, six months 906.8s, p = 0.007). The control group showed no significant change (baseline 683.8s, three months 718.2s, six months 710.8s). These improvements in exercise performance were not accompanied by significant changes in myocardial oxygen consumption as measured by submaximum and peak rate pressure product. Submaximum heart rate in the power group was lowered by training. Mean heart rate, exercise performance and haemostatic factors were influenced positively by exercise training after coronary artery surgery. Power (strength) training was safe and beneficial in these previously untrained cardiac patients. The other aspects of cardiovascular function were not affected to any clinically relevant extent by aerobic or power exercise training. (Abstract shortened by ProQuest.)