Sex differences in the relationship between physical activity levels and cerebral pulsatility

Abstract

BACKGROUND: Greater cerebral blood flow pulsatility, measured as pulsatility index (PI), has recently been under investigation as a risk factor for cognitive impairment and neurodegenerative diseases. Furthermore, physical activity (PA), which has been associated with improved cognitive function and holds therapeutic effects for cardiovascular function, may be linked with lower cerebral pulsatility, especially in postmenopausal women (PMW). PURPOSE: To investigate the relationship between PA and PI in PMW and determine if these relationships are maintained in age-matched men. We hypothesized that there would be an inverse relationship between PA and PI in PMW, and that this relationship would diminish in age-matched men. METHODS: Fifty-two healthy PMW (age 63 ± 4 years) and 25 age-matched men (63 ± 4 years) were recruited for this study. PA was self-reported via the Godin Questionnaire (Godin Score) and using the metabolic equivalent to exercise in minutes per week (MET-Min). Cerebral blood flow was measured through the internal carotid arteries (ICAs), middle cerebral arteries (MCAs), and the basilar artery using 4D Flow MRI. PI was calculated as (maximum flow – minimum flow)/mean flow. RESULTS: There were no significant differences in PA between groups via Godin Score (PMW: 37 ± 21 vs. Men 37 ± 13, p = 1.00) or MET-Min (PMW: 1586 ± 901 vs. Men: 1831 ± 901, p = 0.28). When combined, there was a significant inverse association between MET-Min and basilar PI (r = -0.24, p = 0.04). In PMW, there was a trend for greater MET-Min to be associated with lower basilar PI (r = -0.24, p = 0.08), however this trend was not observed in men (r = -0.25, p = 0.25). Interestingly, in men, there was a significant positive association between MET-Min and MCA PI (r = 0.46, p = 0.03). There were no significant associations observed between PA and ICA PI. CONCLUSION: Greater PA may be linked to lower PI in PMW, but not in in age-matched men. The influence of regular physical activity on cerebral PI may be specific to certain cerebral vessels. This study was funded by the Virginia Horn Henry Research Grant, NIH grant (AG070469-01), and the Wisconsin Alzheimer's Disease Research Center (P30-AG062715). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.