Skin temperature indices to evaluate thermal perceptions and cognitive performance in cold environments

The human body maintains thermoneutrality by regulating skin temperature, so skin temperature has potential as an index for assessing thermal perception. The connection between skin temperature, thermal perception, and cognitive performance is also undergoing deeper investigation. In this study, the local skin temperature (head, face, ear, hand, finger, arm, chest, thigh, calf and foot), thermal perceptions (thermal sensation and thermal comfort), and cognitive performance of 14 young males were recorded for 65 min at -13 degrees C, -5 degrees C and 3 degrees C. Cognitive performance was assessed using a Stroop test, where participants identified the color of words that either matched or conflicted with the word's meaning. The results showed that the drop in ambient temperature resulted in more significant changes in ear, finger, and calf skin temperatures than the decrease in mean skin temperature (MST). Finger skin temperature was strongly linked to the overall thermal perception, and it ranged from 24.48 degrees C to 30.65 degrees C in the thermoneutral range. The quadratic fitting relationships were found in hand, foot, and face between the local skin temperatures and their local thermal perceptions (R-2 > 0.9). Local skin temperatures (hand, foot and face) all recovered to above 25 degrees C when local thermal sensation vote (TSV) and local thermal comfort vote (TCV) were greater than 0. Cognitive performance is correlated strongly with foot skin temperature. Foot temperatures above 28.83 degrees C were associated with better cognitive performance. Regarding thermal perception, the best cognitive performance was achieved with TSVFoot of approximately 1.09. This study provides valuable insights into how local skin temperatures can be used as indicators of thermal perception and cognitive function.