Fig. 1

Experimental protocol. Subjects were asked to rest on an exercise bike for 5 min and then pedal for 20 min, then continued pedaling for 1 min to cool down. After this time, the subjects sat on a chair and immersed forearms in tap water or CO₂ water at 25 °C for 20 min. After immersion, subjects removed their forearms from the bathtub and rested for 10 min. Continuous measurement: skin blood flow, ear canal temperature, skin temperature, heart rate. Arrow down: thermal sensation, thermal comfort