
ALT Experimental protocol (schematic). Each participant completed (a) an exercise protocol and, after a 30-min break, (b) a postural transition protocol. Intervention blocks (cycling; supine) are shaded; block durations are indicated.

ALT Subject-averaged traces and temporal correspondence. (a, d) Subject-averaged, z-scored time series (mean ± 95% CI) for TCD-derived MCAv (purple) and the Temple Brain Flow index (orange), with per-device heart rate below (dashed), for the (a) exercise and (d) postural transition protocols; shading marks the cycling and supine epochs. (b, e) Distributions of subject-level Pearson correlation coefficients between paired MCAv and Brain Flow index traces (median r = 0.795 exercise; r = 0.799 postural; one-sided Wilcoxon signed-rank test). (c, f) Distributions of subject-level heart rate mean absolute percentage error (HR MAPE). Asterisks (*) denote p < 0.001.





















