Please use this identifier to cite or link to this item: http://buratest.brunel.ac.uk/handle/2438/9893
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dc.contributor.authorTrangmar, SJ-
dc.contributor.authorChiesa, ST-
dc.contributor.authorStock, CG-
dc.contributor.authorKalsi, KK-
dc.contributor.authorSecher, NH-
dc.contributor.authorGonzález-Alonso, J-
dc.date.accessioned2015-01-21T15:41:59Z-
dc.date.available2014-07-15-
dc.date.available2015-01-21T15:41:59Z-
dc.date.issued2014-
dc.identifier.citationJournal of Physiology, 592:14, pp. 3143 - 3160, 2014en_US
dc.identifier.issn1469-7793-
dc.identifier.urihttp://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.272104/abstract-
dc.identifier.urihttp://bura.brunel.ac.uk/handle/2438/9893-
dc.descriptionThis article has been made available through the Brunel Open Access Publishing Fund.-
dc.description.abstractKey points: Dehydration accrued during exercise in the heat challenges systemic and locomotor muscle blood flow, but its impact on cerebral blood flow (CBF) and metabolism remains unknown. This study assessed whether dehydration compromises CBF and the cerebral metabolic rate for oxygen (CMRO2) during incremental exercise to exhaustion in trained males. Dehydration induced an early reduction in CBF during progressive exercise, but increased O2 extraction secured CMRO2. In all hydration conditions declining CBF at high exercise intensities was correlated to decreasing arterial carbon dioxide tension and increasing jugular venous plasma noradrenaline. These results suggest that dehydration impairs CBF at high exercise intensities, but this circulatory strain on the human brain does not compromise CMRO2. Intense exercise is associated with a reduction in cerebral blood flow (CBF), but regulation of CBF during strenuous exercise in the heat with dehydration is unclear. We assessed internal (ICA) and common carotid artery (CCA) haemodynamics (indicative of CBF and extra-cranial blood flow), middle cerebral artery velocity (MCA Vmean), arterial-venous differences and blood temperature in 10 trained males during incremental cycling to exhaustion in the heat (35°C) in control, dehydrated and rehydrated states. Dehydration reduced body mass (75.8 ± 3 vs. 78.2 ± 3 kg), increased internal temperature (38.3 ± 0.1 vs. 36.8 ± 0.1°C), impaired exercise capacity (269 ± 11 vs. 336 ± 14 W), and lowered ICA and MCA Vmean by 12-23% without compromising CCA blood flow. During euhydrated incremental exercise on a separate day, however, exercise capacity and ICA, MCA Vmean and CCA dynamics were preserved. The fast decline in cerebral perfusion with dehydration was accompanied by increased O2 extraction (P < 0.05), resulting in a maintained cerebral metabolic rate for oxygen (CMRO2). In all conditions, reductions in ICA and MCA Vmean were associated with declining cerebral vascular conductance, increasing jugular venous noradrenaline, and falling arterial carbon dioxide tension (P aCO 2) (R2 ≥ 0.41, P ≤ 0.01) whereas CCA flow and conductance were related to elevated blood temperature. In conclusion, dehydration accelerated the decline in CBF by decreasing P aCO 2 and enhancing vasoconstrictor activity. However, the circulatory strain on the human brain during maximal exercise does not compromise CMRO2 because of compensatory increases in O2 extraction. © 2014 The Authors.en_US
dc.format.extent3143 - 3160-
dc.format.extent3143 - 3160-
dc.languageeng-
dc.language.isoenen_US
dc.publisherBlackwell Publishing Ltden_US
dc.subjectDehydrationen_US
dc.subjectSystemic and locomotor muscle blood flowen_US
dc.subjectCerebral blood flow (CBF)en_US
dc.titleDehydration affects cerebral blood flow but not its metabolic rate for oxygen during maximal exercise in trained humansen_US
dc.typeArticleen_US
dc.identifier.doihttp://dx.doi.org/10.1113/jphysiol.2014.272104-
dc.relation.isPartOfJournal of Physiology-
dc.relation.isPartOfJournal of Physiology-
pubs.issue14-
pubs.issue14-
pubs.volume592-
pubs.volume592-
pubs.organisational-data/Brunel-
pubs.organisational-data/Brunel/Brunel Staff by College/Department/Division-
pubs.organisational-data/Brunel/Brunel Staff by College/Department/Division/College of Health and Life Sciences-
pubs.organisational-data/Brunel/Brunel Staff by College/Department/Division/College of Health and Life Sciences/Dept of Life Sciences-
pubs.organisational-data/Brunel/Brunel Staff by College/Department/Division/College of Health and Life Sciences/Dept of Life Sciences/Sport-
pubs.organisational-data/Brunel/Leavers-
pubs.organisational-data/Brunel/University Research Centres and Groups-
pubs.organisational-data/Brunel/University Research Centres and Groups/School of Health Sciences and Social Care - URCs and Groups-
pubs.organisational-data/Brunel/University Research Centres and Groups/School of Health Sciences and Social Care - URCs and Groups/Brunel Institute for Ageing Studies-
pubs.organisational-data/Brunel/University Research Centres and Groups/School of Health Sciences and Social Care - URCs and Groups/Brunel Institute of Cancer Genetics and Pharmacogenomics-
pubs.organisational-data/Brunel/University Research Centres and Groups/School of Health Sciences and Social Care - URCs and Groups/Centre for Systems and Synthetic Biology-
Appears in Collections:Sport
Brunel OA Publishing Fund
Dept of Life Sciences Research Papers

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