Thermal regulation and comfort during a mild-cold exposure in young Japanese women complaining of unusual coldness

We examined body core and skin temperatures and thermal comfort in young Japanese women suffering from unusual coldness (C, n = 6). They were selected by interview asking whether they often felt severe coldness even in an air-conditioned environment (20-26°C) and compared with women not suffering from coldness (N, n = 6). Experiments were conducted twice for each subject: 120-min exposure at 23.5°C or 29.5°C after a 40-min baseline at 29.5°C. Mean skin temperature decreased (P < 0.05) from 33.6 ± 0.1°C (mean ± SE) to 31.1 ± 0.1°C and from 33.5 ± 0.1°C to 31.1 ± 0.1°C in C and N during the 23.5°C exposure. Fingertip temperature in C decreased more than in N (P < 0.05; from 35.2 ± 0.1°C to 23.6 ± 0.2°C and from 35.5 ± 0.1°C to 25.6 ± 0.6°C). Those temperatures during the 29.5°C exposure remained at the baseline levels. Rectal temperature during the 23.5°C exposure was maintained at the baseline level in both groups (from 36.9 ± 0.2°C to 36.8 ± 0.1°C and 37.1 ± 0.1°C to 37.0 ± 0.1°C in C and N). The rating scores of cold discomfort for both the body and extremities were greater (P < 0.05) in C than in N. Thus the augmented thermal sensitivity of the body to cold and activated vasoconstriction of the extremities during cold exposure could be the mechanism for the severe coldness felt in C.