Document Detail


Transient cutaneous vasodilatation and hypotension after drinking in dehydrated and exercising men.
MedLine Citation:
PMID:  16123108     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We examined whether oropharyngeal stimulation by drinking released the dehydration-induced suppression of cutaneous vasodilatation and decreased mean arterial pressure (MAP) in exercising subjects, and assessed the effects of hypovolaemia or hyperosmolality alone on these responses. Seven young males underwent four hydration conditions. These were two normal plasma volume (PV) trials: normal plasma osmolality (P(osmol), control trial) and hyperosmolality (DeltaP(osmol) = +11 mosmol (kg H(2)O)(-1)); and two low PV trials: isosmolality (DeltaPV = -310 ml) and hyperosmolality (DeltaPV = -345 ml; DeltaP(osmol) = +9 mosmol (kg H(2)O)(-1)), attained by combined treatment with furosemide (frusemide), hypertonic saline and/or 24 h water restriction. In each trial, the subjects exercised at 60% peak aerobic power for approximately 50 min at 30 degrees C atmospheric temperature and 50% relative humidity. When oesophageal temperature (T(oes)) reached a plateau after approximately 30 min of exercise, the subjects drank 200 ml water at 37.5 degrees C within a minute. Before drinking, forearm vascular conductance (FVC), calculated as forearm blood flow divided by MAP, was lowered by 20-40% in hypovolaemia, hyperosmolality, or both, compared with that in the control trial, despite increased T(oes). After drinking, FVC increased by approximately 20% compared with that before drinking (P < 0.05) in both hyperosmotic trials, but it was greater in normovolaemia than in hypovolaemia (P < 0.05). However, no increases occurred in either isosmotic trial. MAP fell by 4-8 mmHg in both hyperosmotic trials (P < 0.05) after drinking, but more rapidly in normovolaemia than in hypovolaemia. PV and P(osmol) did not change during this period. Thus, oropharyngeal stimulation by drinking released the dehydration-induced suppression of cutaneous vasodilatation and reduced MAP during exercise, and this was accelerated when PV was restored.
Authors:
Yoshi-Ichiro Kamijo; Tadashi Okumoto; Yoshiaki Takeno; Kazunobu Okazaki; Mitsuharu Inaki; Shizue Masuki; Hiroshi Nose
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-08-25
Journal Detail:
Title:  The Journal of physiology     Volume:  568     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-10-17     Completed Date:  2005-12-27     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  689-98     Citation Subset:  IM    
Affiliation:
Department of Sports Medical Sciences, Institute of Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto, Japan.
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MeSH Terms
Descriptor/Qualifier:
Blood Pressure
Blood Volume
Body Temperature Regulation / physiology
Dehydration / physiopathology*
Drinking / physiology
Exercise / physiology*
Humans
Hypovolemia / physiopathology
Male
Regional Blood Flow / physiology
Skin / blood supply*
Vasodilation / physiology*
Water-Electrolyte Balance / physiology*
Comments/Corrections

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