Abstract 157: The Sex-Specific Influence of Adiposity on Blood Pressure During Physical and Mental Challenges in Adolescence

Abstract

Greater blood pressure (BP) reactivity and slower BP recovery from physical and mental challenges predict future hypertension. Males exhibit higher BP than females throughout their reproductive age and, as such, have a higher prevalence of hypertension. Excess body-fat is a major risk factor for hypertension in both males and females. We investigated whether BP reactivity and recovery from physical and mental challenges differ between adolescent males and females, and whether these hemodynamic parameters are associated with resting BP and are influenced by excess body-fat in a sex-specific manner. In 285 male and 311 female adolescents (age 12-18 years), we quantified visceral fat (VF) with magnetic resonance imaging and total body fat (TBF) with bioimpedance and measured systolic BP (SBP) beat-by-beat at rest and during physical (10-min standing) and mental (2-min math test) challenges. Our results showed that in both sexes, BP reactivity and BP recovery for both challenges (adjusted for age, height and initial BP) correlated closely with resting BP (0.03 ≤ r2 ≤ 0.34). In addition, for both physical and mental challenges, males versus females showed greater BP reactivity (by 3.5 mm Hg, p<0.0001 and by 2.6 mmHg, p=0.02, respectively) and no difference in BP recovery. VF correlated positively with BP reactivity to the physical challenge only and in males only (r=0.18, p=0.007), and this correlation was independent of TBF (r=0.21, p=0.002). Consistent with these results, additional adjustment for VF diminished the sex difference in BP reactivity to the physical but not mental challenge (from 3.5 to 2.7 mm Hg, p=0.01). No relationship was observed between VF and BP recovery from either challenge and in either sex. This is the first study to show sex differences exist not only in BP adaptation to daily activities, but also in the way VF influences this adaptation. Overall, our findings suggest the need for sex-specific prevention and treatment of hypertension.