Document Detail


Comparison of short-term aerobic training and high aerobic power on tolerance to uncompensable heat stress.
MedLine Citation:
PMID:  10416998     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study investigated whether, in subjects of moderate aerobic fitness, short-term aerobic training could replicate the improved physiological responses to exercise-heat stress observed in individuals with a high level of aerobic fitness. Males of moderate (MF; <50 ml x kg(-1) min(-1) VO2peak, n = 8) and high (HF; >55 ml x kg(-1) x min(-1) VO2peak, n = 8) aerobic fitness walked at 3.5 km x h(-1) in the heat (40 degrees C, 30% relative humidity) wearing nuclear, biological, and chemical protective clothing. Tests were conducted once on HF subjects and on MF subjects before (MF-Pre) and after (MF-Post) a 2-week program 6 d x week(-1) of daily aerobic training (1 h treadmill exercise at 65% VO2peak for 12 d, 22 degrees C, 40% relative humidity). The training significantly increased VO2peak by 6.5%, while heart rate (fc) and rectal temperature (Tre) rise decreased during exercise in a thermoneutral environment. HF had lower body mass and body fat content than MF, and VO2peak remained lower in MF pre-or post-training. In the heat, MF-Post had a decreased skin temperature (Tsk) and an increased sweat rate compared with MF-Pre, but no changes were observed in fc, Tre, or tolerance time (TT). No significant differences during the first 60 min in Tre and fc were observed between the MF-Post and the HF subjects, though the HF subjects exhibited a lower Tsk. The endpoint Tre, deltaTre, and TT remained significantly higher in HF than in either the MF-Pre or MF-Post subjects. It was concluded that, in preparation for exercise in an uncompensable heat stress environment, short-term aerobic training offers little, if any, benefit and is not an adequate substitute for a high level of aerobic fitness resulting from habitual exercise and training.
Authors:
S S Cheung; T M McLellan
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  70     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-09-02     Completed Date:  1999-09-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  637-43     Citation Subset:  IM; S    
Affiliation:
Defence and Civil Institute of Environmental Medicine, Human Protection and Performance Section, Toronto, Ont., Canada.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Adolescent
Adult
Body Mass Index
Body Temperature
Exercise Test
Exercise Therapy / methods*
Exercise Tolerance*
Heart Rate
Heat Stress Disorders / etiology,  metabolism,  physiopathology*,  prevention & control*
Humans
Humidity
Male
Oxygen Consumption
Physical Fitness*
Protective Clothing / adverse effects
Pulmonary Gas Exchange
Sweating
Time Factors

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


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