Relative importance of different surface regions for thermal comfort in humans

Abstract

In a previous study, we investigated the contribution of the surface of the face, chest, abdomen, and thigh to thermal comfort by applying local temperature stimulation during whole-body exposure to mild heat or cold. In hot conditions, humans prefer a cool face, and in cold they prefer a warm abdomen. In this study, we extended investigation of regional differences in thermal comfort to the neck, hand, soles, abdomen (Experiment 1), the upper and lower back, upper arm, and abdomen (Experiment 2). The methodology was similar to that used in the previous study. To compare the results of each experiment, we utilized the abdomen as the reference area in these experiments. Thermal comfort feelings were not particularly strong for the limbs and extremities, in spite of the fact that changes in skin temperature induced by local temperature stimulation of the limbs and extremities were always larger than changes that were induced in the more proximal body parts. For the trunk areas, a significant difference in thermal comfort was not observed among the abdomen, and upper and lower back. An exception involved local cooling during whole-body mild cold exposure, wherein the most dominant preference was for a warmer temperature of the abdomen. As for the neck and abdomen, clear differences were observed during local cooling, while no significant difference was observed during local warming. We combined the results for the current and the previous study, and characterized regional differences in thermal comfort and thermal preference for the whole-body surface.

Human behavioral thermoregulation during exercise in the heat

“…Nevertheless, it is well accepted that thermal comfort is often intimately related to skin and core temperatures. At normothermic core temperatures, thermal comfort is largely determined by skin temperature (Gagge et al., ; Cabanac et al., , ; Mower, ; Bulcao et al., ; Pellerin et al., ; Yao et al., ; Nakamura et al., , ). However, should core temperature be displaced from normothermia, thermal discomfort ensues, while improvements in thermal comfort occur as a result of a thermal stimulus (i.e., skin cooling or warming) that aims to restore normothermia (Chatonnet & Cabanac, ; Cabanac et al., ; Mower, ; Attia & Engel, , ).…”

Relationship of the Cold‐Heat Sensation of the Limbs and Abdomen with Physiological Biomarkers

“…Nakamura et al [13], using stimulated hot and cold conditions, found that humans prefer a cooler face and warmer abdomen, respectively. They also reported that the distal region (e.g., limbs and extremities) is less sensitive to changes in thermal pleasantness than the trunk [14]. Interestingly, the phenomenon of cold limbs is reported to have a genetic basis [15].…”

Local body cooling to improve sleep quality and thermal comfort in a hot environment

“…Moreover, studies indicate that there are regional differences in the thermal comfort response to thermal stimuli. Nakamura et al 30,31 reported that the limb and extremities are less influential for producing thermal comfort than the trunk areas; during mild heat exposure, facial and neck cooling was judged the most comfortable. Based on their influence on whole-body sensation, Zhang 32 reported that the most influential body parts are back, chest, and pelvis.…”

“…Local cooling was applied to the head (together with the neck) and upper back because cooling of these parts has been shown to be effective in improving the thermal comfort of subjects who were awake. [30][31][32][33][34][35] The lower body sections were not cooled as people are most comfortable with warm feet 32 and warm feet have been shown to promote the rapid onset of sleep. 39 Wyndham observed that the daytime temperature for comfort (26.6°C) was higher than the nighttime comfort temperature (24.7°C) in the hot humid tropics of Australia when air-conditioning…”