Cardiovascular regulation after acute dynamic exercise.

摘要

While cardiovascular regulation during exercise has been studied extensively, cardiovascular regulation after dynamic exercise has received little attention in the past. Since aerobic exercise is a putative treatment for cardiovascular diseases, research directed at understanding cardiovascular regulation after acute exercise is necessary to understand the mechanisms through which chronic exercise may ameliorate these conditions. The research presented here investigated the effects of acute, dynamic exercise on several integral aspects of cardiovascular regulation. Specifically, baroreflex regulation of heart rate, sympathetic vasoconstrictor outflow, and vascular resistance were studied.;One hr of moderate-intensity dynamic exercise produced prolonged vasodilation that resolved by two hr post-exercise, augmented the responsiveness of carotid baroreflex regulation of heart rate during the first hr of recovery, but did not alter tonic cardiac vagal tone (estimated by spectral analysis of R-R interval variability). The increased responsiveness of baroreflex heart rate regulation is likely to oppose rather than contribute to the reduced arterial pressure observed post-exercise. The persistent vasodilation appeared to be mediated in two ways. First, baroreflex control of sympathetic outflow was altered such that sympathetic outflow was less at any arterial pressure. Second, transduction of sympathetic activity into vascular resistance was altered such that vascular resistance was less at any level of sympathetic outflow. These findings indicate that post-exercise arterial pressure reductions are mediated by a persistent vasodilation resulting from both neural and vascular phenomena. Thus, acute, dynamic exercise produces dramatic changes in cardiovascular regulation on several levels.