The Effect of Exercise on Intrinsic Myocardial Performance
Systolic time intervals were performed on 49 male subjects. Twenty-eight subjects were inactive with respect to a continuing exercise program and were classified as a sedentary group. Twenty-one subjects were physically active and were classified as an active group. The active group was composed of 12 members who were moderately active and nine members of a college track team. Using analysis of covariance no significant difference was found in the total duration of electromechanical systole (QS2), left ventricular ejection time (LVET), or the preejection period (PEP) between the moderately active subgroup and the members of the track team. However, a highly significant difference was found between the sedentary and the active group in the QS2 and PEP. The LVET was not significantly different.
The results of this study appear to be consistent with the hypothesis that an increase in intrinsic myocardial performance is associated with physical conditioning. In addition, it is suggested that published equations for the QS2 interval and the PEP may be applicable only to sedentary individuals.
- Physical conditioning
- Noninvasive techniques
- Left ventricular ejection time
- Pre-ejection period
- QS2 interval
- Myocardial contractility
- Received March 31, 1972.
- Accepted March 12, 1973.
- © 1973 American Heart Association, Inc.