Vascular function in the aging human brain during muscle exertion

Maijian Zhu, Tania Xu Yar Lee, Yu Wen Hsieh, Li Fan Lai, Giancarlo Condello, Cyril J. Donnelly, Marc Smith, Sareena Hanim Hamzah, Boon Hooi Lim, Chih Yang Huang, Nai Fang Chi, Chia Hua Kuo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

To determine how brain oxygenation is stably maintained during advancing age, cerebral oxygenation and hemoglobin were measured real-time at 10 Hz using near-infrared spectroscopy (NIRS) at rest (30 seconds) and during a 10-repeated handgrip strength test (30 seconds) for 834 adults (M/F = 45/55%) aged 20–88 y. The amplitude of cerebral hemodynamic fluctuation was reflected by converting 300 values of % oxygen saturation and hemoglobin of each 30-second phase to standard deviation as indicatives of brain oxygenation variability (BOV) and brain hemodynamic variability (BHV) for each participant. Both BOV (+21–72%) and BHV (+94–158%) increased during the maximal voluntary muscle exertions for all age levels (α < 0.05), suggesting an increased vascular recruitment to maintain oxygen homeostasis in the brain. Intriguingly, BHV was >100 folds for both resting and challenged conditions (α < 0.001) in >80% of adults aged above 50 y despite similar BOV compared with young age counterparts, indicating a huge cost of amplifying hemodynamic oscillation to maintain a stable oxygenation in the aging brain. Since vascular endothelial cells are short-lived, our results implicate a hemodynamic compensation to emergence of daily deficits in replacing senescent endothelial cells after age 50 y.

Original languageEnglish
Pages (from-to)3910-3920
Number of pages11
JournalAging
Volume14
Issue number9
DOIs
StatePublished - 2022

Keywords

  • Endothelial function
  • Frailty
  • Muscle strength
  • Nirs
  • Vascular function

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