Normal variations in body surface electrocardiographic potential distributions during QRS: effects of exercise and exercise training

Total body surface electrocardiographic potential distributions, oxygen uptake (VO2), blood pressure and heart rate were monitored during maximal exercise procedures performed by 26 normal adult subjects (male and female) covering a range from sedentary to fit. Normal variations in the exercise response of the ECG during QRS were found not to be related to variations in the level of cardiovascular fitness as quantified by maximal VO2 or to variations in maximal heart rate and blood pressure. In a second experiment, seven sedentary adult female subjects underwent an exercise training protocol for ten weeks. Maximal exercise tests were performed before and after the training period. Exercise-induced changes in the ECG during QRS were not affected by the physical training. We conclude that normal variations in the exercise response of the ECG during QRS are not related to the level of cardiovascular fitness of the subject.