| Cerebral oxygenation declines at exercise intensities above the respiratory compensation threshold. | |
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MedLine Citation:
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PMID: 17045853 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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During incremental exercise PaCO2 and PETCO2 begin to decline at the respiratory compensation threshold (RCT-GEX). Since PaCO2 alters cerebral blood flow it was hypothesized that there would be a systematic decline in cerebral oxygenation (Cox) measured by near infrared spectroscopy above the RCT (RCT-NIRS). Cardiorespiratory and NIRS responses were simultaneously monitored from the left frontal lobe during incremental exercise in 17 men. All subjects showed a decline in Cox above the RCT-GEX with a 20-40 s delay. Significant differences (P<0.01) were observed between the RCT-GEX and RCT-NIRS for time (9.83 versus 10.39 min), power (198 versus 212 W) and oxygen uptake (2.31 versus 2.43 L min-1). Intra-class correlations for power and absolute VO2 were 0.97 and 0.98, respectively. Bland-Altman analysis revealed no outliers for any of the variables. The results suggested that the decrease in Cox observed above the RCT was most likely due to a reduction in cerebral blood flow mediated by a decline in PaCO2. This decline in Cox could reduce neuronal activation thereby limiting maximal exercise capacity in healthy subjects. |
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Authors:
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Yagesh Bhambhani; Rohit Malik; Swapan Mookerjee |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-08-30 |
Journal Detail:
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Title: Respiratory physiology & neurobiology Volume: 156 ISSN: 1569-9048 ISO Abbreviation: Respir Physiol Neurobiol Publication Date: 2007 May |
Date Detail:
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Created Date: 2007-03-05 Completed Date: 2007-05-08 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 101140022 Medline TA: Respir Physiol Neurobiol Country: Netherlands |
Other Details:
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Languages: eng Pagination: 196-202 Citation Subset: IM |
Affiliation:
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Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada. yagesh.bhambhani@ualberta.ca |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological Adult Anaerobic Threshold / physiology Brain / blood supply*, metabolism Carbon Dioxide / blood* Cerebrovascular Circulation / physiology* Exercise Test Exercise Tolerance / physiology* Fatigue / blood Humans Male Oxygen / blood Oxygen Consumption / physiology* Physical Exertion / physiology Pulmonary Ventilation / physiology Reference Values Respiratory Mechanics / physiology* Statistics, Nonparametric |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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