Document Detail


Muscle sympathetic responses during orthostasis in heat-stressed individuals.
MedLine Citation:
PMID:  21688084     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: Whole-body heat stress compromises the control of blood pressure during an orthostatic challenge, although the extent to which this occurs can vary greatly between individuals. The mechanism(s) responsible for these varying responses remain unclear. This study tested the hypothesis that the individuals who are best able to tolerate an orthostatic challenge while heat stressed are the ones with the largest increase in sympathetic activity during orthostasis, indexed from recordings of muscle sympathetic nerve activity (MSNA).
METHODS: MSNA, arterial blood pressure, and heart rate were recorded from 11 healthy volunteers throughout passive whole-body heating and during 15 min of 60° head-up tilt (HUT) or until the onset of pre-syncopal symptoms.
RESULTS: Whole-body heating significantly increased core temperature (~0.9°C), supine heart rate and MSNA. Eight of 11 subjects developed pre-syncopal symptoms resulting in early termination of HUT. The HUT tolerance time was positively correlated (R = 0.82, P = 0.01) with the increase in MSNA by HUT.
CONCLUSION: These data suggest that the individuals with the largest increase in MSNA during upright tilt have the greatest capacity to withstand the orthostatic challenge while heat stressed.
Authors:
Jian Cui; Manabu Shibasaki; David A Low; David M Keller; Scott L Davis; Craig G Crandall
Related Documents :
1463414 - Intraocular pressure reduction with phxa34, a new prostaglandin analogue, in patients w...
8233314 - Focal and diffuse visual field defects: their relationship to intraocular pressure.
19865054 - Intraocular pressure measurements with the newly reconfigured ocuton s*tt-mv self-tonom...
11464074 - Interaction between delta-9-tetrahydrocannabinol and indomethacin.
21825894 - Temporary sacral nerve stimulation alters rectal sensory function: a physiological study.
14668594 - Impact of two different types of anal retractor on fecal continence after fistula repai...
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-06-18
Journal Detail:
Title:  Clinical autonomic research : official journal of the Clinical Autonomic Research Society     Volume:  21     ISSN:  1619-1560     ISO Abbreviation:  Clin. Auton. Res.     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-11-09     Completed Date:  2012-03-08     Revised Date:  2013-06-28    
Medline Journal Info:
Nlm Unique ID:  9106549     Medline TA:  Clin Auton Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  381-7     Citation Subset:  IM    
Affiliation:
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adult
Dizziness / complications*
Female
Heat Stress Disorders / pathology*
Humans
Male
Muscle, Skeletal / physiopathology*
Sympathetic Nervous System / pathology*
Grant Support
ID/Acronym/Agency:
HL-61388/HL/NHLBI NIH HHS; HL-84072/HL/NHLBI NIH HHS; R01 HL061388/HL/NHLBI NIH HHS; R01 HL084072/HL/NHLBI NIH HHS
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Long-term cultivation of in vitro Apis mellifera cells by gene transfer of human c-myc proto-oncogen...
Next Document:  Effect of shRNA Mediated Down-Regulation of Annexin A2 on Biological Behavior of Human Lung Adencarc...