A Study on the Exercise Electrocardiogram of the Elementary School Girls

The authors studied the elementary school girls' electrocardiographic pattern during and after exercise for the purpose of making a research in its physiological variations. Telemetered radioelectrocardiography was employed to record the electrocardiogram during exercise. The unipolar precordial lead V_5 was recorded. The step test was employed as a workload. The results were as follows: 1. With regard to the changes in heart-rate, this study corroborated the results of the previous studies researched by many investigators in every particular. From the results of heart-rate, it was considered that the girl was not able to apply to the exercise so quickly as the boy and was inferior to the boy in the abilities of endurance and recovery. 2. The curve representing the changes in QTT interval resembled the corresponding curve of QT interval, although they differed in several particulars, i.e., the two curves had rapid falls when exercise began, gradual falls until the exercise ceased and rapid rises when the exercise stopped. Therefore, the authors recommended the utilization of QTT interval in the exercise electrocardiogram instead of QT interval, for it was impossible to measure exactly when heart-rate was frequent. The girl's intervals were generally shorter than the boy's. 3. The changes in QTc and QTTc resembled mutually, too, i.e., the two curves reached the maximum immediately after the beginning of exercise and the minimum in about one minute after the end of exercise and exceeded again slightly the resting level in the duration of recovery process. 4. The changes in the voltage of T wave were classified into four types. The appearance rates of A and B types were approximately equal in both sexes. However, there were comparatively many C types and a few D types in girls, as compared to a few C types and many D types in boys. 5. The ST-segment depressions and elevations were seen for four girls. As they varied only under 0.05 mV and recovered the former state in the duration of recovery process, they were thought to be innocent variant. The authors believe that the results studied in this paper will help as a guide to the training methods to maintain and promote our health