Cardiovascular hemodynamics during stress in premenopausal versus postmenopausal women

OBJECTIVE: After menopause, women are at an increased risk of cardiovascular disease. The present study assessed cardiovascular hemodynamics in premenopausal versus postmenopausal women, with a focus on systemic vascular resistance (SVR) at rest and during stress. Sympathetic nervous system activity and cardiovascular adrenergic receptor (AR) function were also examined. METHODS: A total of 90 women (45 premenopausal and 45 postmenopausal) completed a laboratory protocol composed of a resting baseline and four mental stress tasks. Measurements included blood pressure, cardiac output, SVR, and plasma catecholamine level. In addition, alpha- and beta-AR responsiveness to the infusion of selective pharmacological agonists was assessed. RESULTS: Compared with premenopausal women, postmenopausal women were characterized by similar blood pressure but lower cardiac output and higher SVR, both at rest and during stress (Ps < 0.05). Postmenopausal women also had higher baseline plasma norepinephrine levels (P = 0.007) and reduced beta-AR responsiveness (P = 0.02), although differences in beta-AR responsiveness may have been confounded by aging effects. CONCLUSIONS: After menopause, women exhibit altered sympathetic nervous system activity and a sustained increase in hemodynamic load that may contribute to pathological structural and functional changes in the heart and blood vessels.