Figure 2.

Associations of total cognitive composite scores with aerobic fitness percentile (Figure 2a), vascular endothelial function assessed by brachial artery flow-mediated dilation (FMD) (Figure 2b), and cerebrovascular reactivity (CVR) to changes in end-tidal CO₂ from hypo- to hypercapnia (Figure 2c) in the sedentary (black circles) and endurance-trained (gray circles) middle-aged participants. Aerobic fitness percentile was calculated based on age- and sex-adjusted regression established by the American College of Sports Medicine. Thin black and gray lines represent linear regression for the sedentary and endurance-trained subjects respectively. Thick black lines represent linear regression for all subjects.