Document Detail


Effects of 6 versus 12 days of heat acclimation on heat tolerance in lightly exercising men wearing protective clothing.
MedLine Citation:
PMID:  7588688     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study investigated the influence of 6 versus 12 days of heat acclimation on the tolerance of low-intensity exercise in the heat while wearing protective clothing. Sixteen young men were acclimated by treadmill walking (50% of each subject's maximal aerobic power for 60 min.day-1) in a climatic chamber [40 degrees C dry bulb (db), 30% relative humidity] for either 6 consecutive days or two 6-day periods, separated by a 1-day rest. Before and after heat acclimation, the subjects performed a heat-exercise test (1.34 m.s-1, 0% grade; 40 degrees C db, 30% relative humidity), either under control conditions [wearing normal light combat clothing (continuous exercise; n = 5)] or when wearing protective clothing resistant against nuclear, biological, and chemical (NBC) agents (repeated bouts of 15-min walk + 15-min rest; n = 8). Criteria for halting the test exercise were a rectal temperature (Tre) of 39.3 degrees C, a heart rate (fc) > or = 95% of the subject's observed maximum, unwillingness of the subject to continue, or the elapse of 150 min. Heat acclimation decreased overall test values of Tre, fc, and mean skin temperature for both control and protective clothing conditions. When wearing normal combat clothing, acclimation responses were about twice as large after 12 than after 6 days, but the response was not increased by longer acclimation when wearing NBC protective clothing. Both 6 and 12 days of acclimation increased tolerance times in NBC protective clothing by about 15 min [from 97 (4) to 112 (6) min and from 108 (10) to 120 (10) min for 6 and 12 days, respectively]. We conclude that the physiological strain and limitation of heat-exercise tolerance imposed by wearing NBC protective clothing are not reduced if heat acclimation is prolonged from 6 to 12 days.
Authors:
Y Aoyagi; T M McLellan; R J Shephard
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of applied physiology and occupational physiology     Volume:  71     ISSN:  0301-5548     ISO Abbreviation:  Eur J Appl Physiol Occup Physiol     Publication Date:  1995  
Date Detail:
Created Date:  1995-12-13     Completed Date:  1995-12-13     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0410266     Medline TA:  Eur J Appl Physiol Occup Physiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  187-96     Citation Subset:  IM; S    
Affiliation:
Graduate Department of Community Health, University of Toronto, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Acclimatization*
Adult
Body Temperature
Heart Rate
Hot Temperature*
Humans
Male
Military Personnel
Physical Exertion*
Protective Clothing*
Pulmonary Gas Exchange
Rectum
Skin Temperature
Sweating
Time Factors

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


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