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Respir Physiol Neurobiol. 2012 Oct 15;184(1):97-105. doi: 10.1016/j.resp.2012.07.014. Epub 2012 Aug 16.

Regional cerebral blood flow distribution during exercise: influence of oxygen.

Author information

1
University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, British Columbia, Canada. kurt.smith@ubc.ca

Abstract

We investigated regional changes in cerebral artery velocity during incremental exercise while breathing normoxia (21% O2), hyperoxia (100% O2) or hypoxia (16% O2) [n=10; randomized cross over design]. Middle cerebral and posterior cerebral arterial velocities (MCAv and PCAv) were measured continuously using transcranial Doppler ultrasound. At rest, only PCAv was reduced (-7%; P=0.016) with hyperoxia. During low-intensity exercise (40% workload maximum [Wmax]) MCAv (+17 cms(-1); +14cms(-1)) and PCAv (+9cms(-1); +14 cms(-1)) were increased above baseline with normoxia and hypoxia, respectively (P<0.05). The absolute increase from rest in MCAv was greater than the increase in PCAv between 40 and 80% Wmax with normoxia; this greater increase in MCAv was also evident at 60% Wmax with hypoxia and hyperoxia. Hyperoxic exercise resulted in larger absolute (+19 cms(-1)) and relative (+40%) increases in PCAv compared with normoxia. Our findings highlight the selective changes in PCAv during hyperoxic incremental exercise.

PMID:
22926137
DOI:
10.1016/j.resp.2012.07.014
[Indexed for MEDLINE]

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