Sex-specific effects of intensity and dose of physical activity on BOLD-fMRI cerebrovascular reactivity and cerebral pulsatility

Cerebrovascular reactivity (CVR) and cerebral pulsatility (CP) are important indicators of cerebrovascular health, which are associated with physical activity (PA). While sex differences influence the impact of PA on cerebrovascular health, sex-specific effects of PA intensity and dose on CP and CVR remains unknown. This study aimed to evaluate the sex-specific effects of self-reported PA dose and intensity on CVR and CP. The Human Connectome Project - Aging dataset was used, including 626 participants (350 females, 276 males) aged 36-85. The effect of menopausal status was also assessed. Resting state fMRI data was used to estimate both CVR and CP. Weekly self-reported PA was quantified as metabolic equivalent of task. Females presented a unique non-linear relationship between relative CVR and total PA in the cerebral cortex. Females and menopausal subgroups revealed negative linear relationships with total and walking PA in occipital and cingulate regions. Males exhibited negative linear relationships between total and vigorous PA and CVR in parietal and cingulate regions. Postmenopausal females showed greater reductions across more regions in CP than other groups. Overall, males and females appear to benefit from different amounts and intensities of PA, with menopause status influencing the effect of PA on cerebrovascular health.