The exercise-influenced T-wave and its relation to sustained treadmill running

The electrocardiograms from fifty middle-aged males were recorded at the end of each stage of a three-stage treadmill walk and also at the end of each minute of a ten-minute post-exercise recovery period. The height of the T-waves decreased during the treadmill walk until the mean height was less than the mean height of the T-waves recorded at rest. The T-wave amplitudes increased during the first minute of the recovery period and then, during the next four minutes of the recovery period, the heights of the T-waves decreased until the mean of the heights became less than the mean height of the T-wave recorded at rest. The mean heights then remained relatively stable during the remaining five minutes of the post-exercise rest period. The subjects then ran to apparent exhaustion on a treadmill and the duration of these periods of running was correlated with the time which elapsed before the heights of the T-waves, recorded at the end of the treadmill walk, returned to their pre-exercise amplitudes. The correlation was insignificant and can not be used for predicting the length of time a middle-aged male can endure sustained running.