To evaluate the cardiovascular changes associated with menopause, we studied hemodynamics at rest, ambulatory blood pressure, and left ventricular structure in a biracial cohort of pre- and postmenopausal women of similar age, race, weight, and blood pressure. Despite similar levels of blood pressure, postmenopausal women had a higher indexed peripheral resistance (2,722 +/- 757 vs 2,262 +/- 661 dynes.s.m(2)/cm(5), p <0.01) and a lower cardiac index (2.64 +/- 0.73 vs 3.10 +/- 0.71 L/min.m(2), p <0.01) than premenopausal women. Postmenopausal women also had less nocturnal decreases in both systolic (15 +/- 8 vs 19 +/- 8 mm Hg, p <0.01) and diastolic (12 +/- 6 vs 15 +/- 6 mm Hg, p = 0.05) pressures during ambulatory monitoring and higher levels of hematocrit (40 +/- 2% vs 38 +/- 3%, p <0.01). In association with this greater hemodynamic load, postmenopausal women had evidence of early concentric left ventricular remodeling, manifested by a greater relative wall thickness (0.38 +/- 0.06 vs 0.35 +/- 0.06, p <0.01) than that observed in premenopausal women. Differences between pre- and postmenopausal women in hemodynamics, diurnal blood pressure variation, and left ventricular structure were observed in white and African-American subjects. These results suggest that menopause is associated with hemodynamic changes and left ventricular remodeling, which may contribute to the enhanced cardiovascular risk observed in postmenopausal women.