| Ad libitum fluid replacement in military personnel during a 4-h route march. | |
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MedLine Citation:
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PMID: 20142772 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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INTRODUCTION: Opportunities to determine optimal rates of fluid ingestion could reduce the mass soldiers might need to carry on military missions. PURPOSE: The first objective was to evaluate the effects of an ad libitum fluid replacement strategy on total body water (TBW), core temperature, serum sodium concentrations [Na+], and plasma osmolality (POsm). The second objective was to determine if an ad libitum water intake was sufficient to maintain these variables during exercise. A third objective was to determine if changes in body mass are an accurate measure of changes in TBW. METHODS: A field study was conducted with 15 soldiers performing a 16.4-km route march. The average age of 15 subjects was 27 yr (SD = 4.6 yr). RESULTS: Their mean hourly ad libitum fluid intake was 383 mL (SD = 150 mL). Predicted sweat rate was 626 +/-122 mL.h-1. Despite an average body mass loss of 1.0 kg (SD = 0.50 kg) TBW, POsm and serum [Na+] did not change significantly during exercise. There was a significant (P < 0.05) linear relationship with a negative slope between postexercise serum [Na+] and changes in both body mass and percentage of TBW. Postexercise POsm and serum [Na+] were significantly related (P < 0.05). Higher postexercise percentage of TBW was associated with lower postexercise POsm and serum [Na+] levels. There was no relation between percent body mass loss and postexercise core temperature (38.1 degrees C +/- 0.6 degrees C). CONCLUSIONS: A mean ad libitum water intake of 383 mL.h-1, replacing approximately 61% of body mass losses during 4 h of exercise, maintained TBW, core temperature, POsm, and serum [Na+] despite a 1.4% body mass loss. A reduction in body mass of 1.4% (1.0 kg) was not associated with a reduction in TBW. |
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Authors:
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Heinrich Nolte; Timothy D Noakes; Bernard Van Vuuren |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 42 ISSN: 1530-0315 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2010 Sep |
Date Detail:
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Created Date: 2010-08-30 Completed Date: 2010-12-13 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: United States |
Other Details:
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Languages: eng Pagination: 1675-80 Citation Subset: IM; S |
Affiliation:
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ERGOnomics TECHnologies, Pretoria, South Africa. heinrich@ergotech.co.za |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Body Temperature / physiology* Body Water / physiology* Drinking / physiology* Exercise / physiology Humans Military Personnel* Osmolar Concentration Sodium / blood Sweat / physiology Weight Loss / physiology Young Adult |
| Chemical | |
Reg. No./Substance:
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7440-23-5/Sodium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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