Abstract
Previous studies have reported that carotid arterial compliance increased by habitual exercise, so that the cardiovagal baroreflex sensitivity increased. This concept is based on the anatomical fact that the arterial baroreceptor is a stretch sensitive receptor, a part of which is located in the carotid sinus. However, we previously reported that neural component of baroreflex sensitivity estimated by R-R interval corresponding end-systolic lumen diameter was greater in physically active young men than that in sedentary, but mechanical component of baroreflex sensitivity estimated by end-systolic lumen diameter corresponding systolic blood pressure was not different between active and sedentary group. We hypothesized that short term exercise training increase arterial baroreflex sensitivity due to the neural alteration but not increase arterial compliance because alteration in neural property will occur faster than that in mechanical property of blood vessel wall. To examine this hypothesis, we estimated baroreflex sensitivity and carotid arterial compliance in elderly subjects before exercise training, and at 2, 6, and 12 weeks after training. Arterial baroreflex sensitivity increased at 2 weeks after training but arterial compliance did not increase at this time point. This result suggests that arterial baroreflex sensitivity increase by short term exercise training, which is probably due to alteration in "neural" arc of the arterial baroreflex. [J Physiol Sci. 2006;56 Suppl:S136]
