Evidence for hysteresis in the cerebral pressure-flow relationship in healthy men

Patrice Brassard*, Hélène Ferland-Dutil, Jonathan D. Smirl, Myriam Paquette, Olivier Le Blanc, Simon Malenfant, Philip N. Ainslie

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)


    The cerebrovasculature is more efficient at compensating for pharmacologically induced transient hypertension versus transient hypotension. Whether this phenomenon exists during nonpharmacologically induced hypertension and hypotension is currently unknown. We compared the percent change in mean velocity in the middle cerebral artery (MCAvmean) per percent change in mean arterial pressure (MAP) (%ΔMCAVmean/%ΔMAP) during transient hypertension and hypotension induced during squatstand maneuvers performed at 0.05 Hz (20-s cycles) and 0.10 Hz (10-s cycles) in 58 male volunteers. %ΔMCAvmean/%ΔMAP was attenuated by 25% (P = 0.03, 0.05 Hz) and 47% (P ˂ 0.0001, 0.10 Hz) during transient hypertension versus hypotension. Thus, these findings indicate that the brain in healthy men is better adapted to compensate for physiologically relevant transient hypertension than hypotension. NEW & NOTEWORTHY The novel finding of this study is that the change in middle cerebral artery mean flow velocity is attenuated during hypertension compared with hypotension physiologically induced by oscillations in blood pressure in men. These results support that the human brain is more effective at compensating for transient hypertension than hypotension.

    Original languageEnglish
    Pages (from-to)H701-H704
    JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
    Issue number4
    Publication statusPublished - 1 Apr 2017


    • Cerebrovascular blood flow
    • Exercise
    • Hypertension
    • Hypotension
    • Hysteresis


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