Journal of Applied Physiology, Vol 39, Issue 3 449-452, Copyright © 1975 by American Physiological Society
Left ventricular dynamics during recovery from exercise
L. D. Horwitz, J. M. Atkins and S. A. Dunbar
Left ventricular dynamics during recovery were measured in dogs, 3 min
after brief periods of mild, moderate, and severe treadmill exercise. As
compared with resting values, stroke volume was unchanged, and the maximum
first derivative of the left ventricular pressure was either unchanged or
slightly elevated. Increases in heart rate of 20, 26, and 46 beats/min for
mild, moderate, and severe exercise appear to be the major factor in
augmenting cardiac output during recovery. With moderate and severe
exercise, left ventricular end-diastolic diameter increased and continued
to be elevated during recovery, whereas end-systolic diameter decreased
during exercise but was elevated above resting values during recovery.
Therefore, with strenuous exercise, a sympathetic-mediated increase in
contractility recedes promptly during the postexercise period but the
Frank-Starling mechanism continues to be a factor.
