| Initial orthostatic hypotension at high altitude. | |
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MedLine Citation:
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PMID: 20586601 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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There are several reports on syncope occurring following standing at high altitude (HA), yet description of the detailed physiological responses to standing at HA are lacking. We examined the hypothesis that appropriate physiological adjustments to upright posture would be compromised at HA (5050 m). Ten healthy volunteers stood up rapidly from supine rest, for 3 min, at sea level and at 5050 m. Beat-to-beat mean arterial blood pressure (MAP, Finometer), middle cerebral artery blood velocity (MCAv, Transcranial Doppler), end-tidal PCO(2) and PO(2), and heart rate (ECG) were recorded continuously. After 14 days at HA, baseline MAP and MCAv were not different to sea level, although HR was elevated. Neither the magnitude of initial (<15 s) responses to standing, nor the time course of initial recovery differed at HA compared with sea level (p > 0.05). By 3 min of standing, MAP was restored to supine values both at sea level (-3 +/- 12 mmHg) and HA (4 +/- 10 mmHg), although there was more complete recovery of HR at sea level (+13 +/- 10 b.min(-1), p = 0.02 vs. + 23 +/- 10 b.min(-1), p = 0.01). Reduced MCAv at 3 min was comparable at sea level and altitude (both -16%). These data indicate that initial cardiovascular and cerebrovascular responses to standing are unaltered when partially acclimatized to HA. |
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Authors:
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Kate N Thomas; Keith R Burgess; Rishi Basnyat; Samuel J E Lucas; James D Cotter; Jui-Lin Fan; Karen C Peebles; Rebekah A I Lucas; Philip N Ainslie |
Publication Detail:
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Type: Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: High altitude medicine & biology Volume: 11 ISSN: 1557-8682 ISO Abbreviation: High Alt. Med. Biol. Publication Date: 2010 |
Date Detail:
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Created Date: 2010-06-30 Completed Date: 2010-10-21 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901183 Medline TA: High Alt Med Biol Country: United States |
Other Details:
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Languages: eng Pagination: 163-7 Citation Subset: IM; S |
Affiliation:
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University of Otago, Dunedin, New Zealand. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acclimatization
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physiology* Adaptation, Physiological / physiology Adult Altitude Blood Flow Velocity / physiology Blood Pressure / physiology Cerebrovascular Circulation / physiology Hemodynamics / physiology Humans Hypotension, Orthostatic / complications, physiopathology* Male Oxygen Consumption / physiology Posture / physiology* Syncope / diagnosis*, etiology Young Adult |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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