Proceedings o/The Fifth Int. Conj. on Environmental Ergonomics THE EFFECT OF CLOTHING ON THERMOREGULATION AND SEASONAL COLD ACCLIMATION

The extremities play an important role in the control of dry and wet heat loss in human thermoregulation (Hirata, 1989). With this in mind, whether the extremities are covered or uncovered by clothing might have some influence on heat loss from the human body to the environment; and, hence, result in different responses of core temperature between covered and uncovered extremities due to clothing. Furthermore, to our knowledge, it is yet unknown what role different types of clothing could play for cold and warm acclimation. In this report, we describe the thermophysiological significance of two different types of clothing under acute cold exposure (Jeong and Tokura, 1988) and furthermore, a role of two different types of clothing for seasonal cold acclimation from summer to winter. METHODS Experiment I. Six healthy males served as subjects. They aged 21.8±5.0 yrs (mean±sE.M.), were 168±1 cm in height, weighed 6O.2±1.6 kg and had l.64±O.02 m2 body surface area. Two different types of clothing were worn by subjects: one garment covering the whole body area except for the face (Iong-sleeves:L-S, weight 2329 g) and the other covering the central body area only (haIf-sleeves: H-S, 1625 g). Each was worn for 160 min at an ambient temperature (Ta) of lOoC and a relative humidity of 50 % in the supine posture. During the first 40 min the subjects were covered with the blanket. Thermoregulatory responses (metabolic heat production, rectal and skin temperatures, body weight loss) and clothing microclimate temperature were compared between L-S and H-S. Experiment II. Subjects were divided hlto two groups. Each group consisted of 6-7 female adults. The subjects in group A always dressed themselves in skirts for three months from September to November during the daytime, while those in group B dressed themselves in full-trousers during the identical periods. Thermoregulatory responses and heart rates were compared at Ta of 25°C and 15°C between two groups in August, October and December. At the time of the test, the subjects in both group wore the same garments: T-shirt with half-sleeves and short pants