Research Paper Volume 14, Issue 9 pp 3910—3920
Vascular function in the aging human brain during muscle exertion
- 1 Laboratory of Exercise Biochemistry, University of Taipei, Taipei City 11153, Taiwan, ROC
- 2 Department of Medicine and Surgery, University of Parma, Via Gramsci, Parma 43126, Italy
- 3 Rehabilitation Research Institute of Singapore, Nanyang Technological University, Singapore
- 4 Body Composition Technologies, Pty Ltd., South Perth, Western Australia, Australia
- 5 Centre for Sport and Exercise Sciences, University Malaya, Kuala Lumpur 50603, Malaysia
- 6 Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan, ROC
- 7 Center of General Education, Buddhist Tzu Chi Medical Foundation, Tzu Chi University of Science and Technology, Hualien 970, Taiwan, ROC
- 8 Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan, ROC
- 9 Graduate Institute of Biomedical Sciences, China Medical University, Taichung 404, Taiwan, ROC
- 10 Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taiwan, ROC
- 11 Department of Neurology, Taipei Veterans General Hospital, Taiwan, ROC
Received: September 1, 2021 Accepted: March 8, 2022 Published: May 2, 2022
https://doi.org/10.18632/aging.204052How to Cite
Copyright: © 2022 Zhu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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.