| Skin cooling aids cerebrovascular function more effectively under severe than moderate heat stress. | |
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MedLine Citation:
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PMID: 19946700 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Skin surface cooling has been shown to improve orthostatic tolerance; however, the influence of severe heat stress on cardiovascular and cerebrovascular responses to skin cooling remains unknown. Nine healthy males, resting supine in a water-perfusion suit, were heated to +1.0 and +2.0 degrees C elevation in body core temperature (T (c)). Blood flow velocity in the middle cerebral artery (transcranial Doppler ultrasound), mean arterial pressure (MAP; photoplethysmography), stroke volume (SV; Modelflow), total peripheral resistance (TPR; Modelflow), heart rate (HR; ECG) and the partial pressure of end-tidal carbon dioxide (P(ET)CO(2)) were measured continuously during 1-min baseline and 3-min lower body negative pressure (LBNP, -15 mm Hg) when heated without and again with skin surface cooling. Nine participants tolerated +1 degrees C and six participants reached +2 degrees C. Skin cooling elevated (P = 0.004) MAP ~4% during baseline and LBNP at +1 degrees C T (c). During LBNP, skin cooling increased SV (9%; P = 0.010) and TPR (0.9 mm Hg L(-1) min, P = 0.013) and lowered HR (13 b min(-1), P = 0.012) at +1 degrees C T (c) and +2 degrees C T (c) collectively. At +2 degrees C T (c), skin cooling elevated P(ET)CO(2) ~4.3 mm Hg (P = 0.011) and therefore reduced cerebral vascular resistance ~0.1 mm Hg cm(-1) s at baseline and LBNP (P = 0.012). In conclusion, skin cooling under severe heating and mild orthostatic stress maintained cerebral blood flow more effectively than it did under moderate heating, in conjunction with elevated carbon dioxide pressure, SV and arterial resistance. |
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Authors:
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Rebekah A I Lucas; Philip N Ainslie; Jui-Lin Fan; Luke C Wilson; Kate N Thomas; James D Cotter |
Publication Detail:
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Type: Journal Article Date: 2009-11-28 |
Journal Detail:
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Title: European journal of applied physiology Volume: 109 ISSN: 1439-6327 ISO Abbreviation: Eur. J. Appl. Physiol. Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-04-13 Completed Date: 2010-08-11 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100954790 Medline TA: Eur J Appl Physiol Country: Germany |
Other Details:
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Languages: eng Pagination: 101-8 Citation Subset: IM |
Affiliation:
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Department of Physiology, University of Otago, Dunedin, New Zealand. Lucre175@student.otago.ac.nz |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Blood Flow Velocity / physiology Blood Pressure / physiology Body Temperature Regulation* Cerebrovascular Circulation / physiology* Cold Temperature* Heart Rate / physiology Heat-Shock Response / physiology* Humans Lower Body Negative Pressure Male Middle Cerebral Artery / physiology Regional Blood Flow / physiology Skin Temperature / physiology* Supine Position / physiology Vascular Resistance / physiology Young Adult |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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