[Effects of exercise tolerance on electrocardiogram (ECG) with emphasis laid on younger generation]

Effects of Exercise Tolerance on young healthy adults were studied. The results obtained were as follows. The subjects selected were non-smoking 100 volunteers aged 20 to 25 years old, without anamnesis in respiratory and circulatory systems. Exercise was conducted in an amount 3 times (test 1) or 4 times (test 2) of that in a going up and down test stipulated in the Master two step method. The results were subjected to determine changes in heart rate (HR) and ST, QT time, QT ratio and QX/QT immediately after and 5 minutes after tolerance, using ECG taken prior to the tolerance as a control. 1. Changes in each determination 1) Heart rate (HR) (HR before tolerance: 100%) Hardly any change was observed in test 1. But test 2 showed a marked increase in HR, that is 201.8% and 150.1% immediately after and 5 minutes after tolerance respectively. 2) ST change Test 2 showed ST changes of 0.4mm and 0.1mm immediately after and 5 minutes after tolerance respectively. 3) QT time and QT ratio Test 2 showed QT time of 0.29 sec. and 0.34 sec. immediately after and 5 minutes after tolerance respectively. The ratio tended to decrease as exercise tolerance increases, that is 0.92 and 0.98 in test 1 and 0.77 and 0.93 in test 2 immediately after and 5 minutes after tolerance respectively. 4) QX/QT Test 1 showed QX/QT of 0.48 and 0.49 immediately after and 5 minutes after tolerance respectively. Test 2 showed QX/QT of 0.44 and 0.47 immediately after and 5 minutes after tolerance respectively in ST change. 2. Correlation between HR and each determination HR was significantly correlated with ST changing, that is in test 2 r = -0.410 (p less than 0.01) immediately after tolerance (p less than 0.01). HR was significantly correlated with QT ratio, that is in test 1, r = -0.629, r = -0.653 and r = -0.553 control, immediately after and 5 minutes after tolerance respectively, and in test 2 r = -0.712, r = -0.708 and r = -0.785 control, immediately after and 5 minutes after tolerance respectively (p less than 0.01). 3. Correlation between HR-changing and ST-changing rate. Primary formula, that is, ST = -0.379 + 0.0174x (HR) was obtained in r = 0.672 (p less than 0.01), suggesting that ST-changing rate decreases as HR increases.(ABSTRACT TRUNCATED AT 400 WORDS)