Skin temperature as a thermal controller of exercise intensity

This study examined the role of skin temperature on self-selected exercise intensity (i.e., power output). Eight well-trained, male cyclists completed two 60 min self-paced cycling bouts during which they completed as much work as possible. Using a liquid-perfused suit, skin temperature (TSk) was changed during the two trials such that TSk either started hot and was cooled (H to C) or started cold and was heated (C to H) throughout exercise. Pre-exercise core temperatures (TC) and heart rates (HR) were similar between trials, while TSk, thermal comfort and thermal sensation were higher in H to C. The change in TSk was similar in magnitude during the two trials. Work completed was greatest in C to H, which was attributed to a higher initial power output. TC was similar between trials. HR was similar until 35 min had elapsed, after which it became lower in H to C. The perception of effort increased similarly between the two trials, while thermal comfort and thermal sensation generally reflected the changes observed in TSk. These results indicate that upon exercise commencement TSk and the accompanying thermal perceptions are important inputs in the initial selection of exercise intensity.