Perception of Thermal Comfort during Skin Cooling and Heating

Abstract

Due to the static and dynamic activity of the skin temperature sensors, the cutaneous thermal afferent information is dependent on the rate and direction of the temperature change, which would suggest different perceptions of temperature and of thermal comfort during skin heating and cooling. This hypothesis was tested in the present study. Subjects (N = 12; 6 females and 6 males) donned a water-perfused suit (WPS) in which the temperature was varied in a saw-tooth manner in the range from 27 to 42 °C. The rate of change of temperature of the water perfusing the suit (TWPS) was 1.2 °C min−1 during both the heating and cooling phases. The trial was repeated thrice, with subjects reporting their perception of the temperature and thermal comfort at each 3 °C change in TWPS. In addition, subjects were instructed to report when they perceived TWPS uncomfortably cool and warm during cooling and heating, respectively. Subjects reproducibly identified the boundaries of their Thermal Comfort Zone (TCZ), defined as the lower (Tlow) and upper (Thigh) temperatures at which subjects reported slight thermal discomfort. During the heating phase, Tlow and Thigh were 30.0 ± 1.5 °C and 35.1 ± 2.9 °C, respectively. During the cooling phase, the boundary temperatures of Tlow and Thigh were 35.4 ± 1.9 °C and 38.7 ± 2.3 °C, respectively. The direction of the change in the cutaneous temperature stimulus affects the boundaries of the TCZ, such that they are higher during cooling and lower during heating. These findings are explained on the basis of the neurophysiology of thermal perception. From an applied perspective, the most important observation of the present study was the strong correlation between the perception of thermal comfort and the behavioral regulation of thermal comfort. Although it is not surprising that the action of regulating thermal comfort is aligned with its perception, this link has not been proven for humans in previous studies. The results therefore provide a sound basis to consider ratings of thermal comfort as reflecting behavioral actions to achieve the sensation of thermal neutrality.

New Advances in Human Thermophysiology

“…Mekjavic and colleagues presented a strong correlation between the perception of thermal comfort and the behavioural regulation of thermal comfort, which was not proved by previous studies [ 21 ]. Moreover, they showed that gender and age are two important factors that explain thermal comfort variability [ 21 ]. These results are important to consider in future thermal comfort evaluations.…”

“…Finally, assessing thermal comfort is of great interest for estimating the conditions where most humans would feel comfortable in an everyday environment [ 21 ]. Mekjavic and colleagues presented a strong correlation between the perception of thermal comfort and the behavioural regulation of thermal comfort, which was not proved by previous studies [ 21 ]. Moreover, they showed that gender and age are two important factors that explain thermal comfort variability [ 21 ].…”

Effects of cutaneous administration of an over-the-counter menthol cream during temperate-water immersion for exercise-induced hyperthermia in men

“…Perceived thermal sensation ( Brazaitis et al, 2014 ), perceived thermal discomfort ( Mekjavic et al, 2021 ), and blood pressure (BP) were measured at the end of the baseline and exercise, at the onset and throughout TWI (every 5 min), and post TWI. The thermal sensation scale ranged from 1 (very cold) to 9 (very hot), with 5 being neutral.…”

Clothing Thermophysiological Comfort: A Textile Science Perspective

“…Recently, neurophysiological studies have gained large popularity to complement psychophysical studies (or subjective assessment), as it is sometimes difficult to assess the effect of the external stimulus using psychophysical scales [260]. The technique involves the observation of the electrical and chemical activity of the human brain in response to external stimuli [275,276], which are recorded using various advanced techniques, such as electroencephalography, transcranial magnetic stimulation, positron emission tomography, and functional magnetic resonance imaging. The cutaneous thermal and wetness cues originating at the thermal and mechanoreceptors of the human skin travel through four regions to generate a neural response [2,260].…”