Sex differences in pulmonary and systemic vascular function at rest and during exercise in healthy middle-aged adults

Our aim was to conduct a sex-disaggregated analysis of pulmonary and systemic vascular function in healthy individuals both at rest and during submaximal exercise. Healthy individuals underwent right-heart catheterization at rest and during submaximal cycling. Hemodynamic data were collected in a control state and with moderate exercise. Pulmonary and systemic vascular variables including: compliance, resistance, and elastance were calculated, indexed to body surface area (BSA), adjusted for age and compared between male and female sex. Thirty-six individuals (18M/18F; 54 ± 7 vs. 58 ± 6 years, p = 0.04) were included. When adjusted for age and indexed to BSA, total pulmonary resistance (TPulmR) (516 ± 73 vs. 424 ± 118 WU m^-2, p = 0.03) and pulmonary arterial elastance (PEa) (0.41 ± 0.1 vs. 0.32 ± 0.1 mmHg ml^-1 m², p = 0.03) were higher in females vs. males. Both pulmonary (Cpa) and systemic compliance (Csa) were lower in females vs. males however lost significance with adjustment for age. Systemic arterial elastance (SEa) was higher in females (1.65 ± 0.29 vs. 1.31 ± 0.24 mmHg ml^-1, p = 0.05). Secondary analyses demonstrated significant correlations between age and PVR (r = 0.33, p = 0.05), TPulmR (r = 0.35, p = 0.04), Cpa (r = -0.48, p < 0.01), and PEa (r = 0.37, p = 0.03). During exercise, there were greater increases in TPulmR (p = 0.02) and PEa (p = 0.01) in females vs. males. In conclusion, TPulmR and PEa are significantly higher at rest and exercise in females vs. males. Cpa and Csa were lower in females, however this may have been confounded by age. Our results are consistent with the notion that indices of pulmonary and systemic vascular load are higher, related to both older age and female sex, independent of heart failure.