Disentangling the Effects of Daily Stress, Sleep, and Sex Hormones on Accelerated Vascular Aging in Midlife Women

In the last 20 years, deaths due to cardiovascular disease (CVD) have increased by up to 30% in midlife women. This increase in CVD risk in midlife women is at least partially explained by the declines in estradiol (E2) that occur across the menopausal transition. This loss of E2 induces vascular dysfunction, a major contributor to increased CVD risk. Nevertheless, we have shown that declines in vascular function are evident in some midlife premenopausal women, suggesting that vascular dysfunction-associated CVD risk cannot solely be explained by the loss of E2. Emerging factors that may help explain vascular dysfunction in midlife women include greater emotional vulnerability to daily stressors and poorer sleep health. However, not yet know is the extent to which daily stress and sleep health independently impact vascular function in midlife premenopausal women or the degree to which these associations are influenced by E2. The objective of this project is to test the central hypothesis that (a) greater negative affective responsivity to daily stressors and (b) greater sleep variability will each be related to more severe declines in vascular function in midlife premenopausal women and that these associations will be magnified during E2 suppression (simulated menopause) compared to the follicular phase of the menstrual cycle/placebo phase of hormonal contraception. We will assess affective responsitivy to daily stressors and device-measured sleep characteristics for 10 consecutive days and cutaneous microvascular endothelial function before and during pharmacological E2 suppression. The investigators will assess multiple dynamic aspects of daily stress processes for 10 consecutive days (mobile app). Investigators will concurrently objectively assess sleep variability (ActiGraph wGT3X). Immediately before and after completion of these ambulatory assessments, Investigators will assess microvascular endothelial function using intradermal microdialysis coupled with laser Doppler flowmetry. Participants will complete two 10-day measurement bursts:The first will occur during the follicular phase of their menstrual cycle or the low hormone/placebo phase of hormonal contraception; The second will occur during supression of endogenous ovarian hormone production via GnRH antagonist ganirelix acetate.