Document Detail

Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans.
MedLine Citation:
PMID:  20298707     Owner:  NLM     Status:  MEDLINE    
Hypohydration caused by exercise in the heat attenuates autonomic thermoregulation such as sweating and skin blood flow in humans. In contrast, it remains unknown if behavioral thermoregulation is modulated during hypohydration. We assume that thermal unpleasantness could drive the behavioral response, and would also be modulated during hypohydration. Nine healthy young men participated in the present study. Body and skin temperatures were monitored. Ratings of thermal sensation and pleasantness were conducted. After approximately 45 min rest at 27 degrees C, they performed 50-min cycling exercise, which was at the level of 40% of heart rate range at 35 degrees C (hypohydration trial) or at the level of 10% of heart rate range at 23 degrees C (control trial), respectively. Subjects returned to the rest at 27 degrees C, and the ambient temperature was then changed from 22 to 38 degrees C. Body weight decreased by 0.9+/-0.1% immediately after exercise in the hypohydration trial and 0.3+/-0.1% in the control trial. In the cold, no significant difference in thermal sensation or pleasantness was observed between trials. There was no significant difference in thermal pleasantness between trials in the heat, although thermal sensation in the heat (32.5-36 degrees C) was significantly lower in the hypohydration trial than in the control trial. In addition, laser Doppler flow of the skin and sweat rate were attenuated in the heat in the hypohydration trial. These results may indicate that mild hypohydration after exercise in the heat has no influence on behavioral responses to the heat.
Ken Tokizawa; Saki Yasuhara; Mayumi Nakamura; Yuki Uchida; Larry I Crawshaw; Kei Nagashima
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-15
Journal Detail:
Title:  Physiology & behavior     Volume:  100     ISSN:  1873-507X     ISO Abbreviation:  Physiol. Behav.     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-05-21     Completed Date:  2010-09-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0151504     Medline TA:  Physiol Behav     Country:  United States    
Other Details:
Languages:  eng     Pagination:  340-5     Citation Subset:  IM    
Copyright Information:
(c) 2010 Elsevier Inc. All rights reserved.
Laboratory of Integrative Physiology, Health and Welfare, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan.
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MeSH Terms
Autonomic Nervous System / physiopathology*
Body Temperature
Body Temperature Regulation*
Body Weight
Dehydration / etiology*,  physiopathology*,  psychology
Hot Temperature*
Osmolar Concentration
Regional Blood Flow
Skin / blood supply
Skin Temperature
Temperature Sense
Young Adult

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

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