This study was conducted to investigate how different levels of illumination below 1,000 lx would affect the autonomic and behavioral temperature regulation of humans. Seven healthy college-aged women (20+/-0 years) volunteered to participate in this study. They were exposed to a temperature of 26 degrees C in 320 lx for 30 min ('Equilibrium') followed by 700 lx or 70 lx for 30 min (stage 1). After stage 1, they were exposed to 20 degrees C for 30 min in the same illumination as in stage 1 (stage 2). In stage 2 the subjects were instructed to select and wear the clothing they needed for their thermal comfort. The data obtained were analyzed by paired t-test and repeated measures of analysis of variance. Forearm skin blood flow tended to remain steady in 700 lx but decreased markedly in 70 lx in stage 1. There were no significant differences between subjective thermal responses of the subjects experiencing 700 lx or 70 lx in both stages although the subjects felt cooler in stage 2 than in stage 1. The subjects were likely to prefer wearing heavier clothing in 70 lx than in 700 lx. It was concluded that vasoconstriction in the upper limbs occurred more strongly in dim light, which might result in different clothing preferences in a cool environment from those associated with brighter light intensity.

The experiment was conducted to investigate the human thermoregulatory responses during rest, exercise and recovery at Ta 20 degrees C and 60% R.H. under the conditions of wearing two different types of clothing. Six healthy men wore two types of clothing: one covering the whole body area except the head (Type A, weight 1656 g), and the other covering only the trunk, upper arms and thighs (Type B, weight 996 g). The level of rectal temperature was kept significantly higher in Type B than in Type A during rest and recovery. The increased and decreased rates of rectal temperature during exercise and recovery were significantly greater in Type A than in Type B, respectively. These findings are discussed from the viewpoint of the differences of skin temperatures of the extremities between Type A and Type B.

We compared the circadian rhythm of human rectal temperature with two different types of clothing at an ambient temperature of 27.5 degrees +/- 0.5 degrees C and a relative humidity of 40 +/- 10%. One clothing covered the whole body area except for the head, hands and feet (Type A, weight 475 g, 0.98 clo), the other covered the trunk, upper arms and thighs (Type B, weight 366 g, 0.93 clo). Major findings are summarized as follows: (1) Late evening fall after retiring and a morning rise after rising in the rectal temperature rhythm were significantly quicker in Type B than in Type A. (2) Late evening rise after retiring and a morning fall after rising in the skin temperatures of the extremities were quicker in Type B than in Type A. (3) A range of oscillation in the circadian rectal temperature rhythm was significantly larger in Type B than in Type A. It was suggested that the quicker late evening rise and morning fall of the skin temperatures in the extremities after retiring and rising, respectively, might be responsible for the quicker late evening fall and morning rise of the circadian rectal temperature.

The study investigates the clothes-wearing behaviors of female college students based on differences in indoor heating systems and cold sensitivity. The respondents included a total of 281 female college students living in South Korea and China. Data were analyzed through an ANOVA and, a paired t-test based on SPSS 21.0. Korean students were less dependent on winter clothing than Chinese students for the whole body parts except for the trunk. Korean students were more likely to feel coldness more but wore less clothing. Korean students' clothes-wearing behaviors with respect to coldness depended on the indoor heating system. Korean students tended to buy warmer clothing, although they preferred not to wear undergarments and tended to wear and to wear less winter clothing. Chinese students showed more active clothes-wearing behaviors to keep their feet warm. Finally, groups divided by indoor heating systems and cold sensitivity showed different clothes-wearing behaviors in comparison to those groups based only on indoor heating systems. Even in similar weather conditions, clothes-wearing behaviors for cold adaptation depended on the indoor heating systems and cold sensitivity. The results suggest that this perspective should be taken into consideration when evaluating clothes-wearing behaviors of certain groups or individuals.

We have compared the human thermoregulatory responses and clothing microclimate temperature when the body core-shell ratio was changed by wearing two different forms of garment. Each was worn for 160 min at an ambient temperature of 10 degrees C and a relative humidity of 50% by six healthy males in the supine posture. One garment covered the whole body area except for the face (long-sleeves: L-S), the other covered the central body area alone (half-sleeves: H-S). Major findings are summarized as follows: 1) Rectal temperature was kept higher by H-S than L-S even though L-S showed higher thermal resistance values. 2) The standard deviation of rectal temperature was smaller in H-S. 3) Trunk skin and clothing microclimate temperatures were also kept higher by H-S. We suggest that the reduced level of rectal temperature in L-S might be ascribed to a different pattern of venous return originating in the mechanisms of the counter-current heat exchange system: the venous return from the periphery into the thoracic and abdominal areas being cooler in L-S than in H-S.