Figure 5.

A and B: linear regression analysis demonstrating the relationships between age and MCAv time constant (τ; A) and $\text{P}{\text{ET}}_{\text{C}{\text{O}}_2}$ time constant (n = 71, females = 38; B). Solid line represents the regression fit for males, and dotted line represents the regression fit for female participants. Hierarchical regression models (P value and R²) are presented for the relationship with age (model 1), the relationship with sex (model 2), and the moderator relationship of the sex-dependent relationship with age (model 3). Slope coefficients (β) of the relationship with age are presented for males and females separately (model 3). MCAv, middle cerebral artery velocity; $\text{P}{\text{ET}}_{\text{C}{\text{O}}_2}$, end-tidal carbon dioxide.