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- Title
Cerebral blood flow, frontal lobe oxygenation and intra-arterial blood pressure during sprint exercise in normoxia and severe acute hypoxia in humans.
- Authors
Curtelin, David; Morales-Alamo, David; Torres-Peralta, Rafael; Rasmussen, Peter; Martin-Rincon, Marcos; Perez-Valera, Mario; Siebenmann, Christoph; Pérez-Suárez, Ismael; Cherouveim, Evgenia; Sheel, A. William; Lundby, Carsten; Calbet, José A. L.
- Abstract
Cerebral blood flow (CBF) is regulated to secure brain O2 delivery while simultaneously avoiding hyperperfusion; however, both requisites may conflict during sprint exercise. To determine whether brain O2 delivery or CBF is prioritized, young men performed sprint exercise in normoxia and hypoxia (PIO2 = 73 mmHg). During the sprints, cardiac output increased to ∼22 L min−1, mean arterial pressure to ∼131 mmHg and peak systolic blood pressure ranged between 200 and 304 mmHg. Middle-cerebral artery velocity (MCAv) increased to peak values (∼16%) after 7.5 s and decreased to pre-exercise values towards the end of the sprint. When the sprints in normoxia were preceded by a reduced PETCO2, CBF and frontal lobe oxygenation decreased in parallel (r = 0.93, P < 0.01). In hypoxia, MCAv was increased by 25%, due to a 26% greater vascular conductance, despite 4–6 mmHg lower PaCO2 in hypoxia than normoxia. This vasodilation fully accounted for the 22 % lower CaO2 in hypoxia, leading to a similar brain O2 delivery during the sprints regardless of PIO2. In conclusion, when a conflict exists between preserving brain O2 delivery or restraining CBF to avoid potential damage by an elevated perfusion pressure, the priority is given to brain O2 delivery.
- Publication
Journal of Cerebral Blood Flow & Metabolism, 2018, Vol 38, Issue 1, p136
- ISSN
0271-678X
- Publication type
Article
- DOI
10.1177/0271678X17691986