title: Acute exercise stress reveals cerebrovascular benefits associated with moderate gains in cardiorespiratory fitness.
abstract: Elevated cardiorespiratory fitness improves resting cerebral perfusion, although to what extent this is further amplified during acute exposure to exercise stress and the corresponding implications for cerebral oxygenation remain unknown. To examine this, we recruited 12 moderately active and 12 sedentary healthy males. Middle cerebral artery blood velocity (MCAv) and prefrontal cortical oxyhemoglobin (cO(2)Hb) concentration were monitored continuously at rest and throughout an incremental cycling test to exhaustion. Despite a subtle elevation in the maximal oxygen uptake (active: 52±9 ml/kg per minute versus sedentary: 33±5 ml/kg per minute, P<0.05), resting MCAv was not different between groups. However, more marked increases in both MCAv (+28±13% versus +18±6%, P<0.05) and cO(2)Hb (+5±4% versus -2±3%, P<0.05) were observed in the active group during the transition from low- to moderate-intensity exercise. Collectively, these findings indicate that the long-term benefits associated with moderate increase in physical activity are not observed in the resting state and only become apparent when the cerebrovasculature is challenged by acute exertional stress. This has important clinical implications when assessing the true extent of cerebrovascular adaptation.
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
authors.forename: Julien V
authors.initials: JV
authors.lastname: Brugniaux
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Marley
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Hodson
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: New
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
authors.forename: Damian M
authors.initials: DM
authors.lastname: Bailey
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D020768:Middle Cerebral Artery / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012146:Rest / Q000502:physiology; D057185:Sedentary Behavior; D013312:Stress, Physiological / Q000502:physiology; D055815:Young Adult