| Acute intermittent hypoxia exposures enhance arterial oxygen delivery. | |
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MedLine Citation:
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PMID: 20660087 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Physiological adaptations to intermittent hypoxia (IH) conditioning are based on the cumulative effect of repeated IH exposures. The present study sought to test the hypothesis that acute IH exposures would promote arterial O(2) delivery and regional tissue oxygenation. Changes in arterial O(2) saturation (SaO(2), oximeter), forearm muscle and cerebral tissue oxygenations (SmO(2) and ScO(2), near-infrared spectroscopy) were compared during five repeated hypoxia exposures (10 +/- 0.2% O(2) for 5-min each) interposed with four-minute inhalation of room air in 11 healthy subjects (24 +/- 0.9 y). Baseline, prehypoxia partial pressure of end-tidal O(2) (P(ET)O(2), mass spectrometer) and SaO(2) (107 +/- 2 mmHg and 97.3 +/- 0.3%) were decreased (P < 0.05) after the first bout as compared with those during normoxia prior to the second (94 +/- 2 mmHg and 96.2 +/- 0.4%) and the fifth (92 +/- 3 mmHg and 95.7 +/- 0.7%) episodes of IH exposures, whereas partial pressure of end-tidal CO(2), tidal volume and breathing frequency were similar. Arterial O(2) dissociation in terms of per unit decrease in P(ET)O(2) during hypoxia, i.e. the slope of SaO(2)/P(ET)O(2), was augmented (P = 0.0025) from 0.71 +/- 0.09%/mmHg during the first hypoxia bout to 1.39 +/- 0.15%/mmHg and 1.47 +/- 0.16%/mmHg during the second and the fifth bouts, respectively. Fractional muscle tissue O(2) extraction rate (SmO(2)D, i.e. normalized difference between SaO(2) and SmO(2)) progressively decreased (P < 0.01) during IH; however, fractional cerebral tissue O(2) extraction rate (ScO(2)D, i.e. normalized difference between SaO(2) and ScO(2)) did not decrease during hypoxia (P = 0.94). ScO(2)D during normoxia tended to increase (P = 0.089) following repeated IH exposures. We conclude that enhanced arterial O(2) delivery with repeated IH exposures serves as a compensatory mechanism to potentiate O(2) availability during hypoxia. |
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Authors:
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Peizhen Zhang; H Fred Downey; Xiangrong Shi |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-07-21 |
Journal Detail:
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Title: Experimental biology and medicine (Maywood, N.J.) Volume: 235 ISSN: 1535-3699 ISO Abbreviation: Exp. Biol. Med. (Maywood) Publication Date: 2010 Sep |
Date Detail:
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Created Date: 2010-08-23 Completed Date: 2010-09-29 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100973463 Medline TA: Exp Biol Med (Maywood) Country: England |
Other Details:
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Languages: eng Pagination: 1134-41 Citation Subset: IM |
Affiliation:
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Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological Anoxia / physiopathology* Arteries Female Humans Male Oxygen Partial Pressure Respiration Respiratory Physiological Phenomena Spectroscopy, Near-Infrared Tidal Volume Young Adult |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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