Sex Differences in Blood Pressure Hemodynamics in Middle-Aged Adults With Overweight and Obesity.

Abstract

High blood pressure (BP) is the strongest modifiable risk factor for cardiovascular disease. Overweight/obesity is a major risk factor of high BP. Multiple sex differences exist in mechanistic pathways that increase BP in overweight/obesity. They may result in a sex-specific pattern of BP hemodynamics-males and females may vary in the relative contributions of stroke volume, total peripheral resistance (TPR), and heart rate to higher BP. We investigated this possibility in a population-based sample of middle-aged adults (36-65 years). The total sample (n=618) included 289 males and 329 females; 79% of males and 66% of females were overweight. In all, we measured BP, stroke volume, TPR, and heart rate beat-by-beat during a 52-minute protocol that included changes in posture and mental stress. We assessed the relative contributions of stroke volume, TPR, and heart rate to BP at each minute of the protocol. We observed marked sex differences in BP hemodynamics in overweight/obese individuals: the main determinant of higher BP was TPR in males (49% versus only 35% in females, P=0.008), whereas it was stroke volume in females (51% versus only 35% in males, P=0.006). These sex differences were most apparent when standing or sitting at rest. No such differences were seen in normal-weight individuals in whom the main determinant of higher BP was TPR in both sexes. Our study suggests that, in middle-aged adults, marked sex differences exist in BP hemodynamics, contributing to high BP in overweight/obese but not normal-weight individuals. As such, this study may contribute to precision medicine in hypertension.