Document Detail

Static and dynamic changes in carotid artery diameter in humans during and after strenuous exercise.
MedLine Citation:
PMID:  12766246     Owner:  NLM     Status:  MEDLINE    
Arterial baroreflex function is altered by dynamic exercise, but it is not clear to what extent baroreflex changes are due to altered transduction of pressure into deformation of the barosensory vessel wall. In this study we measured changes in mean common carotid artery diameter and the pulsatile pressure : diameter ratio (PDR) during and after dynamic exercise. Ten young, healthy subjects performed a graded exercise protocol to exhaustion on a bicycle ergometer. Carotid dimensions were measured with an ultrasound wall-tracking system; central arterial pressure was measured with the use of radial tonometry and the generalized transfer function; baroreflex sensitivity (BRS) was assessed in the post-exercise period by spectral analysis and the sequence method. Data are given as means +/- S.E.M. Mean carotid artery diameter increased during exercise as compared with control levels, but carotid distension amplitude did not change. PDR was reduced from 27.3+/-2.7 to 13.7+/-1.0 microm mmHg(-1). Immediately after stopping exercise, the carotid artery constricted and PDR remained reduced. At 60 min post-exercise, the carotid artery dilated and the PDR increased above control levels (33.9+/-1.4 microm mmHg(-1)). The post-exercise changes in PDR were closely paralleled by those in BRS (0.74< or = r < or =0.83, P<0.05). These changes in mean carotid diameter and PDR suggest that the mean baroreceptor activity level increases during exercise, with reduced dynamic sensitivity; at the end of exercise baroreceptors are suddenly unloaded, then at 1 h post-exercise, baroreceptor activity increases again with increasing dynamic sensitivity. The close correlation between PDR and BRS observed at post-exercise underlies the significance of mechanical factors in arterial baroreflex control.
Péter Studinger; Zsuzsanna Lénárd; Zsuzsanna Kováts; László Kocsis; Mark Kollai
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2003-05-23
Journal Detail:
Title:  The Journal of physiology     Volume:  550     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-15     Completed Date:  2004-03-08     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  575-83     Citation Subset:  IM    
Semmelweis University, Faculty of Medicine, Institute of Human Physiology and Clinical Experimental Research, Budapest, Hungary.
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MeSH Terms
Baroreflex / physiology
Carotid Arteries / anatomy & histology*,  physiology*
Central Venous Pressure / physiology
Cross-Over Studies
Exercise / physiology*
Heart Rate / physiology
Oxygen Consumption / physiology
Pressoreceptors / physiology

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