Preserved ability to blunt sympathetically-mediated vasoconstriction in exercising skeletal muscle of young obese humans

Kanokwan Bunsawat; Georgios Grigoriadis; Elizabeth C Schroeder; Alexander J Rosenberg; Melissa M Rader; Paul J Fadel; Philip S Clifford; Bo Fernhall; Tracy Baynard

doi:10.14814/phy2.14068

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Preserved ability to blunt sympathetically-mediated vasoconstriction in exercising skeletal muscle of young obese humans

Journal article

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Preserved ability to blunt sympathetically-mediated vasoconstriction in exercising skeletal muscle of young obese humans

Kanokwan Bunsawat, Georgios Grigoriadis, Elizabeth C Schroeder, Alexander J Rosenberg, Melissa M Rader, Paul J Fadel, Philip S Clifford, Bo Fernhall and Tracy Baynard

Physiological reports, Vol.7(8), pp.e14068-n/a

04/2019

DOI: 10.14814/phy2.14068

PMCID: PMC6487469

PMID: 31033212

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Abstract

Sympathetic vasoconstriction is attenuated in exercising muscles to assist in matching of blood flow with metabolic demand. This "functional sympatholysis" may be impaired in young obese individuals due to greater sympathetic activation and/or reduced local vasodilatory capacity of both small and large arteries, but this remains poorly understood. We tested the hypothesis that functional sympatholysis is impaired in obese individuals compared with normal-weight counterparts. In 36 obese and normal-weight young healthy adults (n = 18/group), we measured forearm blood flow and calculated forearm vascular conductance (FVC) responses to reflex increases in sympathetic nerve activity induced by lower body negative pressure (LBNP) at rest and during rhythmic handgrip exercise at 15% and 30% of the maximal voluntary contraction (MVC). FVC was normalized to lean forearm mass. In normal-weight individuals, LBNP evoked a decrease in FVC (-16.1 ± 5.7%) in the resting forearm, and the reduction in FVC (15%MVC: -8.1 ± 3.3%; 30%MVC: -1.0 ± 4.0%) was blunted during exercise in an intensity-dependent manner (P < 0.05). Similarly, in obese individuals, LBNP evoked a comparable decrease in FVC (-10.9 ± 5.7%) in the resting forearm, with the reduction in FVC (15%MVC: -9.7 ± 3.3%; 30%MVC: -0.3 ± 4.0%) also blunted during exercise in an intensity-dependent manner (P < 0.05). The magnitude of sympatholysis was similar between groups (P > 0.05) and was intensity-dependent (P < 0.05). Our findings suggest that functional sympatholysis is not impaired in young obese individuals without overt cardiovascular diseases.

Blood Flow Velocity

Exercise

Female

Hand Strength

Humans

Male

Muscle, Skeletal - blood supply

Muscle, Skeletal - innervation

Muscle, Skeletal - physiopathology

Obesity - physiopathology

Reflex

Sympathetic Nervous System - physiopathology

Vasoconstriction

Young Adult

Details

Title: Subtitle: Preserved ability to blunt sympathetically-mediated vasoconstriction in exercising skeletal muscle of young obese humans
Creators: Kanokwan Bunsawat - University of Illinois Chicago
Georgios Grigoriadis - University of Illinois Urbana-Champaign
Elizabeth C Schroeder - University of Illinois Urbana-Champaign
Alexander J Rosenberg - University of Illinois Urbana-Champaign
Melissa M Rader - University of Illinois Urbana-Champaign
Paul J Fadel - The University of Texas at Arlington
Philip S Clifford - University of Illinois Urbana-Champaign
Bo Fernhall - University of Illinois Urbana-Champaign
Tracy Baynard - University of Illinois Urbana-Champaign
Resource Type: Journal article
Publication Details: Physiological reports, Vol.7(8), pp.e14068-n/a
DOI: 10.14814/phy2.14068
PMID: 31033212
PMCID: PMC6487469
NLM abbreviation: Physiol Rep
ISSN: 2051-817X
eISSN: 2051-817X
Language: English
Date published: 04/2019
Academic Unit: Health, Sport, and Human Physiology
Record Identifier: 9984948045002771

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