Effects of Exercise Intervention on Risk Indicators of ECG during Exercise in Males in Their Forties / 中国运动医学杂志

ABSTRACT

Objective To explore the optimal exercise way of improving the risk indicators of electrocardiogram (ECG) during exercise.Methods Twenty-four healthy male subjects aged between 40 and 49 years old were divided randomly into a control group (n=9),a low amount exercise group of 1200 kcal/wk (n=7) and a high amount exercise group of 2000 kcal/wk (n=8).The intensity of the exercise groups was 65％～ 80％VO2max training in the standard 400 m track for 12 weeks.The accelerometer and polar watch were worn to monitor the exercise process.During the exercise,the exercise amount was controlled using the distance and duration while the intensity was controlled using target heart rate.The subjects took part in the graded exercise test before and after the exercise intervention.Twelve lead electrocardiograms were used to measure the indicators of ST segment depression and corrected QT interval dispersion (QTcd) during the exercise.Results The exercise intervention did not result in significant change in ST segment depression,while the QTcd indicator in both the exercise groups decreased significantly after the intervention (P＜0.05).Moreover,the decrease of QTcd indicator in the low amount exercise group was significantly higher than that of the control group (P＜0.05),while the decrease of QTcd indicator in high volume group was higher than that of the control group (P＜0.01).No significant differences were found in the ST segment depression among the 3 different groups.Conclusion The Twelve-weeks exercise interventions with intensity of 65％ ～ 80％ VO2max and exercise amount of 1200 kcal/wk and 2000 kcal/wk have no effect on the ST segment depression during the exercise.However,they can result in significant decrease in the QTcd of ECG during exercise,reducing the risk of exercise-induced myocardial ischemia.