Document Detail


Responses of lean and obese boys to repeated summer exercise in the heat bouts.
MedLine Citation:
PMID:  19127199     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To determine the degree of natural acclimatization and artificially induced acclimation-related changes during repeated exercise in the heat bouts in seven lean and seven obese 9- to 12-yr-old boys during summer months.
METHODS: Beginning at random times during the summer, subjects underwent a 70-min exercise (30% VO(2max)) in the heat exposure (38 degrees C, 50% relative humidity) on six separate days.
RESULTS: On day 1, obese children were less naturally acclimatized as indicated by significantly higher baseline core temperatures (T(c)) (obese = 37.62 +/- 0.06 vs lean = 37.41 +/- 0.06; P < 0.004). By day 6 versus day 1, significant reductions in baseline T(c) were evident in both groups (obese = 37.41 +/- 0.04 vs lean = 37.18 +/- 0.04; both P < 0.05). Baseline T(c) in obese subjects by day 6 was similar to that of lean subjects on day 1. Daily reductions in exercise T(c) were evident in both groups (final exercising T(c) day 1 vs day 6: obese = 38.15 +/- 0.05 vs 37.89 +/- 0.05; lean = 38.17 +/- 0.09 vs 37.72 +/- 0.06 degrees C; both P < 0.001), occurring at a significantly slower rate in obese subjects (final exercise T(c) day 6 - day 1: obese vs lean = -0.26 +/- 0.04 vs -0.45 +/- 0.08 degrees C; P < 0.05). Significant reductions in exercising heart rate (HR) occurred in the lean but not the obese subjects by day 6 (final exercising HR day 1 vs day 6: obese = 132 +/- 3 vs 131 +/- 3, P > 0.05; lean = 138 +/- 3 vs 127 +/- 3 bpm; P < 0.001).
CONCLUSIONS: During summer months, obese children are less naturally heat-acclimatized and subsequently acclimate at a slower rate.
Authors:
Kelly A Dougherty; Mosuk Chow; W Larry Kenney
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  41     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-01-20     Completed Date:  2009-05-08     Revised Date:  2012-06-28    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  279-89     Citation Subset:  IM; S    
Affiliation:
Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-6900, USA. kellydoc35@aol.com
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Body Temperature Regulation / physiology*
Case-Control Studies
Child
Exercise Test
Exercise Tolerance / physiology*
Heart Rate / physiology
Humans
Male
Obesity / physiopathology*
Sweating / physiology
Grant Support
ID/Acronym/Agency:
M01 RR010732-145069/RR/NCRR NIH HHS; M01-RR-10732/RR/NCRR NIH HHS; R01 AG007004/AG/NIA NIH HHS; R01 AG007004-18/AG/NIA NIH HHS; R01 AG007004-19A1/AG/NIA NIH HHS; R01-AG-07004-14/AG/NIA NIH HHS
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