Thermal alliesthesia under whole-body step-change transients

Abstract

A better understanding of the psycho-physiological mechanisms driving human thermal perception during dynamic conditions is important to improve physiological-based thermal comfort models. During thermal transients, the two phenomena of thermal overshoot and thermal alliesthesia concurrently affect thermal comfort. However, they have to date been analysed separately. In this paper, we report the results of an experiment exploring the subjective responses of 16 males and 48 females to four different whole-body warm and cool step-change transients at different times of day (morning/afternoon) and in distinct seasons (summer/autumn). We found that time of day and season both significantly affect the relationship between thermal comfort and thermal sensation. This relationship was then used to predict the thermal comfort overshoot which was compared to the actual comfort vote during the step-change transients. This allowed us to separate the contribution to thermal comfort due to thermal overshoot from that attributed to thermal alliesthesia. We could show that, during the step-change transients, positive alliesthesia increases the level of thermal comfort proportionally to the perceived corrective potential of the whole-body discomfort, and this effect gets stronger as we move away from thermal neutrality.