| Sweat sodium concentration during exercise in the heat in aerobically trained and untrained humans. | |
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MedLine Citation:
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PMID: 21431880 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The purpose of this study was to determine whether sweat sodium concentration ([Na(+)](sweat)) during exercise in the heat differs between aerobically trained and untrained individuals. On three occasions, ten endurance-trained (Tr) and ten untrained (UTr) subjects ([Formula: see text] = 4.0 ± 0.8 vs. 3.4 ± 0.7 L min(-1), respectively; P < 0.05) cycled in a hot-ventilated environment (36 ± 1°C; 25 ± 2% humidity, airflow 2.5 m s(-1)) at three workloads (i.e., 40, 60, and 80% [Formula: see text]). Whole-body (SR(WB)) and back sweat rates (SR(BACK)) were measured. At the conclusion of the study, Na(+) in sweat and blood samples was analyzed to calculate Na(+) secretion and reabsorption rates. SR(WB) and SR(BACK) were highly correlated in Tr and UTr (r = 0.74 and 0.79, respectively; P < 0.0001). In both groups, SR(BACK) increased with the increases in exercise intensity (P < 0.05). Likewise, [Na(+)](sweat) increased with the exercise intensity in both groups (P < 0.05) and it tended to be higher in Tr than in UTr at 60 and 80% [Formula: see text] (~22 mmol L(-1) higher; P = 0.06). However, when normalized for SR(BACK), [Na(+)](sweat) was not different between groups. In both groups, Na(+) secretion and reabsorption rates increased with the increases in SR(BACK) (P < 0.05). However, Na(+) reabsorption rate was lower in the Tr than in the UTr (mean slope = 48 vs. 82 ηmol cm(-2) min(-1); P = 0.03). In conclusion, using a cross-sectional study design, our data suggest that aerobic fitness level does not reduce sweat Na(+) secretion or enhance Na(+) reabsorption during prolonged exercise in the heat that induced high sweat rates. |
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Authors:
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Nassim Hamouti; Juan Del Coso; Juan F Ortega; Ricardo Mora-Rodriguez |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-3-24 |
Journal Detail:
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Title: European journal of applied physiology Volume: - ISSN: 1439-6327 ISO Abbreviation: - Publication Date: 2011 Mar |
Date Detail:
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Created Date: 2011-3-24 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100954790 Medline TA: Eur J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Avda. Carlos III, s/n. 45071, Toledo, Spain. |
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