The electrocardiographic exercise test: Changes in the scalar ecg and in the mean spatial QRS and T vectors in two types of exercise; Effect of absolute and relative body weight and comment on normal standards

Abstract

1. 1. Moderate exercise (walking on the treadmill and stepping up and down) produced statistically significant changes of most electrocardiographic items (both conventional and spatial vectors) in ninety-one middle-aged normal men. 2. 2. Upper and lower limits of the changes of mean spatial QRS and T vectors are presented for both types of exercise for 95 per cent of a population of healthy older men, of which this group is a representative sample. 3. 3. There were significant differences in the postexercise changes of several conventional and vectorial electrocardiographic items between an overweight and an underweight group, but the effect of relative body weight on the exercise electrocardiogram was less pronounced than the effect on the resting electrocardiogram. 4. 4. Absolute body weight is an even less important functional variable than relative body weight and need not be considered in normal standards for the exercise test. 5. 5. Three out of eight conventional electrocardiographic items and two out of seven vectorial electrocardiographic items showed statistically highly significant differences in the response between the step test and walking. 6. 6. The validity of normal standards for the exercise tolerance test is critically discussed, and suggestions for the clinical application of exercise tests are made.