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Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans

Atkinson, CL and Lewis, NCS and Carter, HH and Thijssen, DHJ and Ainslie, PN and Green, DJ (2015) Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans. Journal of Physiology, 593 (23). pp. 5145-5156. ISSN 1469-7793

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Abstract

Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilatation (FMD). Ten healthy male subjects (28 ± 5 years) undertook two 30 min sessions of cycle exercise at 75% HRmax. Prior to exercise, individuals ingested either a placebo or an α1-adrenoreceptor blocker (prazosin; 0.05 mg kg−1). Central haemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after and 60 min after exercise. Cycle exercise increased both mean and antegrade SR (P < 0.001) with retrograde SR also elevated under both conditions (P < 0.001). Pre-exercise FMD was similar on both occasions, and was significantly reduced (27%) immediately following exercise in the placebo condition (t-test, P = 0.03). In contrast, FMD increased (37%) immediately following exercise in the prazosin condition (t-test, P = 0.004, interaction effect P = 0.01). Post-exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post-deflation SR. No differences in FMD or other variables were evident 60 min following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium-dependent dilator activity to determine post-exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: Atkinson, C. L., Lewis, N. C.S., Carter, H. H., Thijssen, D. H.J., Ainslie, P. N. and Green, D. J. (2015), Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans. J Physiol, 593: 5145–5156. which has been published in final form at http://dx.doi.org/10.1113/JP270946. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
Uncontrolled Keywords: 06 Biological Sciences, 11 Medical And Health Sciences
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions: Sport & Exercise Sciences
Publisher: Wiley
Related URLs:
Date Deposited: 20 Jan 2016 10:45
Last Modified: 15 Nov 2016 00:50
DOI or Identification number: 10.1113/JP270946
URI: http://researchonline.ljmu.ac.uk/id/eprint/2696

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