| Keywords |
Thermal comfort; Cutaneous warmth sensation; Body regions; Thermal sensitivity; Conductive heat |
| Abstract |
The purpose of this study was to investigate the effects of heating rate on cutaneous warm thresholds in thermoneutral environments. Fifteen young males participated in this study and their cutaneous thermal thresholds for warmth were measured on 17 body regions using a thermal stimulator at the following three speed conditions: 0.1oC/s, 0.3oC/s, and 0.5oC/s. Subjects pressed the button-switch once they felt ‘warmth’ at first from their neutral-adapting thermal state. The results showed that: (1) among the 17 body regions, only sole temperature at warmth had a significant difference among the three heating rate conditions (31.5 ± 2.0, 32.2 ± 1.4, and 30.8 ± 2.1oC at 0.1oC/s, 0.3oC/s, and 0.5oC/s, respectively; P < 0.05). (2) Noticeable increases in skin temperature to detect the warmth showed significant differences among the three heating rates on the 11 body regions, including the sole (4.0 ± 2.3oC, 4.1 ± 2.4oC, and 5.8 ± 3.2oC at 0.1oC/s, 0.3oC/s, and 0.5oC/s, respectively; P < 0.05), which had increased most rate among the 17 body regions as well (P < 0.01). (3) There were significant differences in the warmth thresholds on the 17 body regions at all the three heating rate conditions. The lower back was the most sensitive to detect warmth while the back calf was the least sensitive (P < 0.05). In summary, the differences between a heating speed of 0.1 and 0.3oC/s did not result in differences in cutaneous warmth thresholds (for the 17 body regions). However, the difference between a heating rate of 0.3 and 0.5oC/s could affect the thermal sensitivity on certain peripheral body regions. These results suggest that differences in heating rate, between 0.1 and 0.5oC/s, had negligible effects on for skin temperature, itself, for the most body regions (except the sole at the 0.5oC/s heating), but increases in skin temperature was affected by the rate of heating speed.
Body regional differences, however, rather than heating rate, were more salient features in cutaneous warm sensitivity. |