Figure 2.

Study protocol. Baseline OCT-A images (*) were captured before each challenge test. Participants completed both challenge tests in the following order: (i) Handgrip test (green arrows) was performed first: OCT-A images were captured following 90 seconds of gripping the hydraulic dynamometer. A 10-minute break for recovery was provided after the handgrip test, and a second set of images were taken, to account for any residual variation in the vasculature following the rest period. (ii) Hypoxia challenge test (blue, dotted arrows): OCT-A images captured following 30 minutes of breathing fraction of inspired oxygen (FiO₂).