| Sex-differences in thermoeffector responses during exercise at fixed requirements for heat loss. | |
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MedLine Citation:
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PMID: 22797311 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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To assess potential mechanisms responsible for the lower sudomotor thermosensitivity in females during exercise, we examined sex-differences in sudomotor function and skin blood flow during exercise performed at progressive increases in the requirement for heat loss. Eight males and eight females cycled at rates of metabolic heat production of 200, 250, and 300 W(.)m(-2) of body surface area, each rate being performed sequentially for 30 min. The protocol was performed in a direct calorimeter to measure evaporative heat loss (EHL) and in a thermal chamber to measure local sweat rate (ventilated capsule, LSR), skin blood flow (laser-Doppler, SkBF), sweat gland activation (modified iodine-paper technique) and sweat gland output (SGO) on the back, chest, and forearm. Despite a similar requirement for heat loss between sexes, significantly lower increases in EHL and LSR were observed in females (p≤0.001). Sex-differences in EHL and LSR were not consistently observed during the first and second exercise periods, while EHL (348±13 vs. 307±9 W(.)m(-2)), and LSR on the back (1.61±0.07 vs. 1.20±0.09 mg(.)min(-1)(.)cm(-2)), chest (1.33±0.06 vs. 1.08±0.09 mg(.)min(-1)(.)cm(-2)) and forearm (1.53±0.07 vs. 1.20±0.06 mg(.)min(-1)(.)cm(-2)) became significantly greater in males during the last exercise period (p<0.05). At each site, differences in LSR were solely due to a greater SGO in males, as opposed to differences in sweat gland activation. In contrast, no sex-differences in SkBF were observed throughout the exercise period. The current study demonstrates that sex-differences in sudomotor function are only evidenced beyond a certain requirement for heat loss, solely through differences in sweat gland output. In contrast, the lower EHL and LSR in females are not paralleled by a lower skin blood flow response. |
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Authors:
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Daniel Gagnon; Glen P Kenny |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-7-12 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2012 Jul |
Date Detail:
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Created Date: 2012-7-16 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1University of Ottawa. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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