Document Detail


Frontal and motor cortex oxygenation during maximal exercise in normoxia and hypoxia.
MedLine Citation:
PMID:  19150853     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Reductions in prefrontal oxygenation near maximal exertion may limit exercise performance by impairing executive functions that influence the decision to stop exercising; however, whether deoxygenation also occurs in motor regions that more directly affect central motor drive is unknown. Multichannel near-infrared spectroscopy was used to compare changes in prefrontal, premotor, and motor cortices during exhaustive exercise. Twenty-three subjects performed two sequential, incremental cycle tests (25 W/min ramp) during acute hypoxia [79 Torr inspired Po(2) (Pi(O(2)))] and normoxia (117 Torr Pi(O(2))) in an environmental chamber. Test order was balanced, and subjects were blinded to chamber pressure. In normoxia, bilateral prefrontal oxygenation was maintained during low- and moderate-intensity exercise but dropped 9.0 +/- 10.7% (mean +/- SD, P < 0.05) before exhaustion (maximal power = 305 +/- 52 W). The pattern and magnitude of deoxygenation were similar in prefrontal, premotor, and motor regions (R(2) > 0.94). In hypoxia, prefrontal oxygenation was reduced 11.1 +/- 14.3% at rest (P < 0.01) and fell another 26.5 +/- 19.5% (P < 0.01) at exhaustion (maximal power = 256 +/- 38 W, P < 0.01). Correlations between regions were high (R(2) > 0.61), but deoxygenation was greater in prefrontal than premotor and motor regions (P < 0.05). Prefrontal, premotor, and motor cortex deoxygenation during high-intensity exercise may contribute to an integrative decision to stop exercise. The accelerated rate of cortical deoxygenation in hypoxia may hasten this effect.
Authors:
Andrew W Subudhi; Brittany R Miramon; Matthew E Granger; Robert C Roach
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2009-01-15
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  106     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-04-01     Completed Date:  2009-05-29     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1153-8     Citation Subset:  IM    
Affiliation:
University of Colorado Altitude Research Center, Denver and Colorado Springs Campuses, Colorado Springs, CO 80918, USA. asubudhi@uccs.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Anaerobic Threshold / physiology
Anoxia / physiopathology*
Carbon Dioxide / blood
Cerebrovascular Circulation / physiology
Exercise / physiology*
Exercise Test
Female
Humans
Male
Motor Cortex / physiology*,  physiopathology
Oxygen Consumption / physiology*
Prefrontal Cortex / physiology*,  physiopathology
Spectroscopy, Near-Infrared
Ultrasonography, Doppler, Transcranial
Grant Support
ID/Acronym/Agency:
HL-070362/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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