Changes in Temperature and Humidity of Various Parts of the Clothed Body During Rest, Exercise, and Recovery

• Published in: Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) Vol. 42; no. 3; pp. 721 - 731
• Main Authors: Shimizu, Hiroko, Hino, Seiji, Shinkai, Shoji, Kurokawa, Yoshika, Tomita, Naoaki, Wada, Takeshi, Watanabe, Tsutomu, Shimizu, Yoshio
• Format: Journal Article
• Language: English; Japanese
• Published: Japan The Japanese Society for Hygiene 1987
• Subjects: Body Temperature; Exercise; Humans; Humidity; Humidity inside clothing; Physical Exertion; Rest; Skin temperature; Sweating; Temperature inside clothing
• ISSN: 0021-5082; 1882-6482
• DOI: 10.1265/jjh.42.721

This paper is an attempt to measure how the temperature and humidity change at various points on the surface of the clothed human body during rest, exercise and recovery in a climatic chamber (26-27°C/50-60%R.H./0.2-0.3cm/sec). Exercise that caused perspiration was performed according to three degrees of intensity. They were 40%, 60%, and 80% of Vo2max., respectively. The results we obtained follow. (A) Changes in the humidities inside clothing. 1) Soon after the exercise began, sweating occured and the humidities rapidly increased. Even after the exercise ended, the humidities continued to increase until finally reaching their maximums. Then they started decreasing gradually. 2) In terms of the rapid increase of the humidity inside clothing, the more intense the exercise was performed, the sooner it started increasing. This rapid increase occured at nearly the same time the subject started sweating. We did not observe any time differences when humidity started rising in terms of the parts of the human body measured. 3) The higher the intensity of the exercise was, the longer time it took the humidity to reach its maximum. The humidity reached the maximum point in a short period of time in the axilla, the upper arm, and the chest, and in a long period of time in the lower back and the abdomen. 4) The higher the intensity of the exercise was, the higher the maximum humidity rose. In terms of the parts of the body measured, the difference in humidities became smaller when the exercise intensity became greater. 5) The greater the exercise intensity became, the lower decreasing rate of the humidity was. The humidity went down the most on the upper arm. These phenomena can be explained as a result of the interrelations among sweating, vapor diffusion, and permeation inside clothing. (B) The changes in temperatures inside clothing. 1) After exercise began, the temperature inside clothing gradually started rising at the exercise intensities of 40% and 60%. However, the temperature went down when the exercise intensity reached 80%, and then went up again later. The parts of the body where the drop was sharpest were the axilla, the upper back, and the lower back. 2) Even after the exrcise ended, the temperature inside clothing continued to rise for some time, eventually reaching a maximum and then falling. 3) As to the necessary time for the temperature to reach its maximum, the higher the exercise intensity was, the longer time it took. The axilla and the upper arm were where it took the longest time to reach its maximum. 4) As far as the maximum temperature is concerned, there was no observable difference attributable to the exercise intensity. The humidity was highest at the axilla and lowest at the upper arm. 5) After the temperature reached its maximum, the temperatures inside clothing keep dropping when the exercise intensity was 80%. At exercise intensities of 40% and 60%, the temperatures went down once and then gradually went up again. These changes inside clothing correspond to the chest skin temperature. We assume that these changes are a result of the heat loss caused by evaporation and heat conductivity through the clothing.