| Impact of age on critical closing pressure of the cerebral circulation during dynamic exercise in humans. | |
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MedLine Citation:
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PMID: 21239464 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Limited information is available regarding cerebral vascular responses to dynamic exercise in older adults. We examined the influence of age on exercise-induced changes in the critical closing pressure (CCP) of the cerebral vasculature. Twelve young and older subjects performed two bouts of steady-state cycling at low and moderate intensities (30% and 50% heart rate reserve). Mean arterial pressure (MAP), middle cerebral artery blood velocity (MCAV) and partial pressure of end-tidal carbon dioxide (P(ET)CO(2)) were measured. CCP was estimated by linear extrapolation of pairs of systolic and diastolic blood pressure and MCAV waveforms. Exercise-induced increases in MAP were greater in older subjects (P<0.01), while mean MCA V (MCA V (mean)) responses to exercise were similar between groups (P=0.59). CCP was elevated from rest during low- and moderate-intensity exercise in both groups (Δ +13±2 young and +22±2 older mmHg, moderate-exercise; P<0.01), with the older subjects exhibiting greater increases in CCP during both exercise intensities (+43±9 vs. +153±45 %rest, moderate-exercise; P=0.04). In contrast, cerebral vascular conductance index (MCA V (mean)/MAP; CVCi) was only decreased during moderate exercise in older subjects (P<0.01) and CVCi was not altered from rest in young subjects during low- or moderate-intensity cycling. No age-group differences were observed in P(ET)CO(2) at rest or during two intensities of exercise (P=0.40). These data demonstrate that older subjects exhibit larger exercise-induced increases in CCP and decreases in CVCi. Thus, ageing is associated with greater increases in cerebral vascular tone during low and moderate intensity dynamic exercise. |
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Authors:
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Shigehiko Ogoh; James P Fisher; Colin N Young; Paul J Fadel |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-1-14 |
Journal Detail:
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Title: Experimental physiology Volume: - ISSN: 1469-445X ISO Abbreviation: - Publication Date: 2011 Jan |
Date Detail:
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Created Date: 2011-1-17 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9002940 Medline TA: Exp Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1 Toyo University; |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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