title: Middle cerebral artery blood velocity during running.
abstract: Running induces characteristic fluctuations in blood pressure (BP) of unknown consequence for organ blood flow. We hypothesized that running-induced BP oscillations are transferred to the cerebral vasculature. In 15 healthy volunteers, transcranial Doppler-determined middle cerebral artery (MCA) blood flow velocity, photoplethysmographic finger BP, and step frequency were measured continuously during three consecutive 5-min intervals of treadmill running at increasing running intensities. Data were analysed in the time and frequency domains. BP data for seven subjects and MCA velocity data for eight subjects, respectively, were excluded from analysis because of insufficient signal quality. Running increased mean arterial pressure and mean MCA velocity and induced rhythmic oscillations in BP and in MCA velocity corresponding to the difference between step rate and heart rate (HR) frequencies. During running, rhythmic oscillations in arterial BP induced by interference between HR and step frequency impact on cerebral blood velocity. For the exercise as a whole, average MCA velocity becomes elevated. These results suggest that running not only induces an increase in regional cerebral blood flow but also challenges cerebral autoregulation.
authors.affiliation: Bispebjerg Hospital Research Unit for Anaesthesia and Intensive Care Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark. tlyngeraa@gmail.com
authors.forename: T S
authors.initials: TS
authors.lastname: Lyngeraa
authors.forename: L M
authors.initials: LM
authors.lastname: Pedersen
authors.forename: T
authors.initials: T
authors.lastname: Mantoni
authors.forename: B
authors.initials: B
authors.lastname: Belhage
authors.forename: L S
authors.initials: LS
authors.lastname: Rasmussen
authors.forename: J J
authors.initials: JJ
authors.lastname: van Lieshout
authors.forename: F C
authors.initials: FC
authors.lastname: Pott
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D062186:Arterial Pressure / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D004562:Electrocardiography; D005385:Fingers / Q000098:blood supply; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D012420:Running / Q000502:physiology*; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult