Fig. 1.

Experimental protocol: CVR was quantified using three consecutive experimental paradigms: (a) RS wherein the subject breathed naturally for 10 min, (b) BH, wherein the subject completed five end-inspiration BHs, and (c) HC, wherein the subject inhaled 5% ${\mathrm{CO}}_2$ for 6 min. Cerebral blood flow, ${\mathrm{EtCO}}_2$, peripheral oxygen saturation, and ABP were continuously monitored throughout the duration of the protocol.