Fig. 5.

The hemodynamic response (${\mathrm{HbO}}_2$ and HHb) averaged for the two far channels on the right forehead and the numeric rating scales (NRS-11) reported every 15 s for the CPTs (CPT) at (a) 1°C and (b) 15°C. The trajectories are averaged across eight subjects that could complete the CPTs at four temperatures (1°C, 5°C, 10°C, and 15°C) for the entire 5 min. The black vertical lines from left to right represent hand immersion into tepid water, hand immersion into cold water, and hand immersion back into tepid water. Error bars represent standard deviation. Adapted from Ref. 64.