Electronic versions

  • Michael M Tymko
    University of Guelph, Ontario
  • Audrey Drapeau
    Université Laval
  • Maria Augusta Vieira-Coelho
    University of Porto
  • Lawrence Labrecque
    Université Laval
  • Sarah Imhoff
    Université Laval
  • Geoff B Coombs
    McMaster University, Hamilton
  • Stephan Langevin
    Université Laval
  • Marc Fortin
    Université Laval
  • Nathalie Châteauvert
    Université Laval
  • Philip N Ainslie
    University of British Columbia, Okanagan
  • Patrice Brassard
    Université Laval

The impact of physiological stressors on cerebral sympathetic nervous activity (SNA) remains controversial. We hypothesized that cerebral noradrenaline (NA) spillover, an index of cerebral SNA, would not change during both submaximal isometric handgrip (HG) exercise followed by a post-exercise circulatory occlusion (PECO), and supine dynamic cycling exercise. Twelve healthy participants (5 females) underwent simultaneous blood sampling from the right radial artery and right internal jugular vein. Right internal jugular vein blood flow was measured using Duplex ultrasound, and tritiated NA was infused through the participants' right superficial forearm vein. Heart rate was recorded via electrocardiogram and blood pressure was monitored using the right radial artery. Total NA spillover increased during HG (P = 0.049), PECO (P = 0.006), and moderate cycling exercise (P = 0.03) compared to rest. Cerebral NA spillover remained unchanged during isometric HG exercise (P = 0.36), PECO after the isometric HG exercise (P = 0.45), and during moderate cycling exercise (P = 0.94) compared to rest. These results indicate that transient increases in blood pressure during acute exercise involving both small and large muscle mass do not engage cerebral SNA in healthy humans. Our findings suggest that cerebral SNA may be non-obligatory for exercise-related cerebrovascular adjustments.

Original languageEnglish
Number of pages12
JournalJournal of Cerebral Blood Flow and Metabolism
Early online date13 Apr 2024
Publication statusE-pub ahead of print - 13 Apr 2024
Externally publishedYes
View graph of relations