Thermophysiological Significance and the Role of Local Clothing in Ambient 10°C Environments

Abstract

In order to understand the role of clothing covering and uncovering the hands, feet, legs, thighs, buttocks and hypogastric region for human thermoregulation at an ambient temperature of 10°C, two series of experiments were conducted on six healthy male subjects wearing three different kinds of clothing in Expt. 1 and four different kinds of clothing in Expt. 2. The three kinds of clothing used in Expt. 1 were, clothing A covering the whole body surface area except the head, clothing B covering the whole body surface area except the head and feet, and clothing C covering the whole body surface area except the head, hands and feet. The four kinds of clothing used in Expt. 2 were clothing C used in Expt. 1, clothing D covering the whole body surface area except the head, hands, feet and legs, clothing E covering the whole body surface area except the head, hands, feet, legs and thighs, and clothing F covering the whole body surface area except the head, hands, feet, legs, thighs, buttocks and hypogastric regions. The starting time of the experiment, the subject measurement variables and the garments used were all kept constant throughout the experiment. The subjects were instructed to enter a chamber at room-temperature and various sensors were attached. The subjects were then instructed to relax until a quasi-steady temperature state was reached. The subjects were then moved into a chamber at 10 ± 0.2°C, 50 ± 5% RH. for two hours. The main results can be summarized as follows: 1) The level of rectal temperatures of subjects wearing clothing C were maintained significantly better than the temperatures of subjects wearing clothing A and B who experienced a significant drop in temperature in the 10°C chamber in Experiment 1. 2) In Experiment 2, the rectal temperatures of subjects wearing clothing E were maintained significantly better than subjects wearing clothing C, D and F, who also experienced significant drops in temperature in the 10°C chamber. These different behavior patterns of rectal temperatures were discussed in terms of the counter-current heat exchange system.