| The cerebral metabolic ratio is not affected by oxygen availability during maximal exercise in humans. | |
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MedLine Citation:
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PMID: 17932151 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Intense exercise decreases the cerebral metabolic ratio of O(2) to carbohydrates (glucose + (1/2) lactate) and the cerebral lactate uptake depends on its arterial concentration, but whether these variables are influenced by O(2) availability is not known. In six males, maximal ergometer rowing increased the arterial lactate to 21.4 +/- 0.8 mm (mean +/- s.e.m.) and arterial-jugular venous (a-v) difference from -0.03 +/- 0.01 mm at rest to 2.52 +/- 0.03 mm (P < 0.05). Arterial glucose was raised to 8.5 +/- 0.5 mm and its a-v difference increased from 1.03 +/- 0.01 to 1.86 +/- 0.02 mm (P < 0.05) in the immediate recovery. During exercise, the cerebral metabolic ratio decreased from 5.67 +/- 0.52 at rest to 1.70 +/- 0.23 (P < 0.05) and remained low in the early recovery. Arterial haemoglobin O(2) saturation was 92.5 +/- 0.2% during exercise with room air, and it reached 87.6 +/- 1.0% and 98.9 +/- 0.2% during exercise with an inspired O(2) fraction of 0.17 and 0.30, respectively. Whilst the increase in a-v lactate difference was attenuated by manipulation of cerebral O(2) availability, the cerebral metabolic ratio was not affected significantly. During maximal rowing, the cerebral metabolic ratio reaches the lowest value with no effect by a moderate change in the arterial O(2) content. These findings suggest that intense whole body exercise is associated with marked imbalance in the cerebral metabolic substrate preferences independent of oxygen availability. |
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Authors:
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S Volianitis; A Fabricius-Bjerre; A Overgaard; M Strømstad; M Bjarrum; C Carlson; N T Petersen; P Rasmussen; N H Secher; H B Nielsen |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial Date: 2007-10-11 |
Journal Detail:
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Title: The Journal of physiology Volume: 586 ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2008 Jan |
Date Detail:
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Created Date: 2008-01-02 Completed Date: 2008-05-19 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: England |
Other Details:
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Languages: eng Pagination: 107-12 Citation Subset: IM |
Affiliation:
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Department of Health Science and Technology, Aalborg University Denmark, Fredrik Bajers Vej 7E4, Aalborg, Denmark. svolian@hst.aau.dk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Anoxia / metabolism, physiopathology Biological Availability Brain / metabolism* Ergometry Exercise / physiology* Humans Hyperoxia / metabolism, physiopathology Lactates / metabolism Male Oxygen / metabolism* Single-Blind Method |
| Chemical | |
Reg. No./Substance:
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0/Lactates; 7782-44-7/Oxygen |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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