Document Detail


The influence of acute and 23 days of intermittent hypoxic exposures on the exercise-induced forehead sweating response.
MedLine Citation:
PMID:  17242947     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effect of acute and 23 days of intermittent exposures to normobaric hypoxia on the forehead sweating response during steady-state exercise was investigated. Eight endurance athletes slept in a normobaric hypoxic room for a minimum of 8 h per day at a simulated altitude equivalent to 2,700 m for 23 days (sleep high-train low regimen). Peak oxygen uptake (VO2(peak)) and peak work rate (WR(peak)) were determined under normoxic (20.9%O(2)) and hypoxic (13.5%O(2)) conditions prior to (pre-IHE), and immediately after (post-IHE) the intermittent hypoxic exposures (IHE). Also, each subject performed three 30-min cycle-ergometry bouts: (1) normoxic exercise at 50% WR(peak) attained in normoxia (control trial; CT); (2) hypoxic exercise at 50% WR(peak) attained in hypoxia (hypoxic relative trial; HRT) and (3) hypoxic exercise at the same absolute work rate as in CT (hypoxic absolute trial; HAT). Exposure to hypoxia induced a 33 and 37% decrease (P < 0.001) in (VO2(peak)) pre-IHE and post-IHE, respectively. Despite similar relative oxygen uptake during HAT pre-IHE and post-IHE, the ratings of perceived whole-body exertion decreased substantially (P < 0.05) post-IHE. Pre-IHE the sweat secretion on the forehead (m(sw)f) was greater (P < 0.01) in the HAT (2.60 (0.80) mg cm(-2) min(-1)) compared to the other two trials (CT = 1.87 (1.09) mg cm(-2) min(-1); HRT = 1.57 (0.82) mg cm(-2) min(-1)) despite a similar exercise-induced elevation in body temperatures, resulting in an augmented (P < 0.01) gain of the sweating response (m(sw)f/Delta T(re)). The augmented (m(sw)f) and m(sw)f/Delta T(re) during the HAT were no longer evident post-IHE. Thus, it appears that exercise sweating on the forehead is potentiated by acute exposure to hypoxia, an effect which can be abolished by 23 days of intermittent hypoxic exposures.
Authors:
Alan Kacin; Petra Golja; Ola Eiken; Michael J Tipton; Igor B Mekjavic
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-01-23
Journal Detail:
Title:  European journal of applied physiology     Volume:  99     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-02-05     Completed Date:  2007-04-20     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  557-66     Citation Subset:  IM    
Affiliation:
Department of Automation, Biocybernetics and Robotics, Institute Jozef Stefan, Jamova 39, Ljubljana, 1000, Slovenia. alan.kacin@vsz.uni-lj.si
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MeSH Terms
Descriptor/Qualifier:
Acclimatization
Acute Disease
Adult
Altitude
Anoxia / blood,  physiopathology*
Blood Pressure
Body Temperature Regulation*
Chronic Disease
Erythrocyte Count
Exercise*
Female
Forehead
Heart Rate
Hematocrit
Humans
Lactic Acid / blood
Male
Oxygen Consumption
Physical Exertion
Respiratory Mechanics
Skin Temperature
Sweating*
Time Factors
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid

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


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