Understanding the influence of the menopause on shear stress mediated cerebral artery dilation at rest and during static handgrip exercise

Abstract

Background: Rapid declines in circulating oestrogen during the menopausal transition has a wide-range of detrimental effects on vascular structure and function. These changes, coupled with elevated blood pressure, may be associated with reductions in cerebral blood flow (CBF), cognition and future dementia risk in post-menopausal women (PMW). With exercise training, the episodic elevation in blood flow and shear stress, induces peripheral vascular adaptation. If CBF and shear stress could be enhanced with exercise, this would likely improve cerebrovascular function in PMW. However, PMW have reduced sensitivity to shear stress, and also exhibit exaggerated blood pressure responses during exercise, which may limit increases in CBF. Whether exercise-induced increases in blood pressure alter flow to the brain in PMW is not known. Previously static handgrip exercise has been used to examine the relationship between blood pressure and CBF. The primary aim of this study is to compare the CBF response to static handgrip exercise in PMW compared with age-matched pre-menopausal women. Secondly, we aim to understand the influence of the menopause on CBF and shear stress flow-mediated dilation (FMD), as a marker of cerebrovascular function; and the possible associations with cognitive function and blood pressure in PMW.