Yoshikatsu Kawashima

Physiological responses and thermal sensations of the elderly in cold and hot environments

Abstract 1. 1. 10 elderly and 10 college-aged females served as subjects in cold and heat environments. The subjects changed into the standard clothing (0.63 clo), and stayed in the neutral environment (25°C) for 23 min, thereafter they were exposed to the cold (10°C) or hot (35°C) environment for 49 min. 2. 2. Then they returned to the neutral environment, and stayed there for 47 min. Oral temperature, skin temperatures at 10 sites, blood pressure and thermal sensation were measured during the experiments. 3. 3. In the cold environment, the elderly could not reduce heat loss by vasoconstriction as did young people, and their blood pressures increased more rapidly than in young people. In the hot environment, the elderly could not promote heat loss by vasodilation as did young people. Moreover, there is a delayed sensitivity to cold for the elderly. Therefore, in the houses of the elderly, it is important to have heating and cooling systems which also includes the areas where the people do not stay for a long period of time (e.g. toilet, passageways).

Preferred temperature of the elderly after cold and heat exposures determined by individual self-selection of air temperature

Abstract 1. 1. The purpose of the study was to investigate the preferred temperature of the elderly after cold and heat exposures. 2. 2. Eight elderly and 9 young females wearing the same type of clothing were exposed to cold (10°C), moderate (25°C) or hot (35°C) environments for 30 min in the exposure room. 3. 3. Then they moved to the self-control room in which the temperature was set at 25°C, and the room temperature increased or decreased continuously by 0.4°C every minute. 4. 4. The subjects were instructed to operate the switch when they felt uncomfortably warm or cool during a 90-min period. 5. 5. In operating the switch, the changing in room temperature shifted to the opposite direction. 6. 6. The ambient temperature was recorded continuously and analyzed as the preferred temperature, which was defined as the midpoint temperature of the crest and trough of temperature records. 7. 7. The preferred temperatures after the cold exposure were significantly higher than those of other exposure conditions in the elderly. 8. 8. On the other hand, in the young, there was no significant difference in the preferred temperature among the exposure conditions. 9. 9. Although the effect of exposure to cold or hot environments decreased in the latter parts of self-control, the elderly still preferred the higher temperature after cold exposure.

Characteristics of the temperature regulation system in the human body

Abstract 1. 1. To study a complex biological system such as human temperature regulation, it is necessary to consider both physiological experiments and theoretical analysis. 2. 2. This paper presents the characteristics of this temperature regulation system obtained from a mathematical model, together with experimental data and the influence of exercise and clothing. 3. 3. The experimental results showed a good agreement with the theoretical results.

A study on body temperature regulation and residential thermal environments of the elderly—I. whole country survey of residential thermal environment and evaluation methods: RTE-index

Abstract 1. 1. As part of “research on environmental comfort,” that is, research which aims to make peoples living environment more comfortable, we attempted to clarify the relation between the living environment of elderly people and physiological and psychological factors. We carried out a comprehensive study with a view to establishing comfort standards for the residential thermal environment, and for creating evaluation and control systems. 2. 2. The comfort of the living environment is closely related to the thermal environment and the temperature-regulation ability of the human body. This ability of the body to regulate temperature develops during childhood and recedes as the adult ages. 3. 3. We therefore carried out: (a) experiments on body-temperature regulation and on special characteristics of the body-temperature regulation of elderly people, (b) a nationwide survey of the actual residential thermal environments of elderly people and (c) a survey of the daily activities of elderly people, and how elderly peoples physiological and psychological conditions change when they are engaged in these activities. 4. 4. As a result of these experiments and surveys, we were able to: (d) formulate standards for evaluation of the residential thermal environment and (e) numerically express the results of systematic evaluation of residential thermal environments of elderly people, by means of a RTE-index.

A study on body temperature regulation and residential thermal environments of the elderly—II. residential thermal environments at the kansai district

Abstract 1. 1. An investigation was carried out on 3 male and 4 female elderly people, from 65 to 78 years ol.d The first survey was made in August and September of 1990 (in summer) and the second in January and February of 1991 (in winter). 2. 2. Matters for investigation were human subjects and thermal environmental elements of houses which were recorded by a portable thermo-recorder and a vinyl resin globe thermometer. Dry bulb temperatures at a height of 0.1 and 1.2 m and wet bulb and globe temperatures at 1.2 m high were recorded in the living room, bedroom, toilet etc., the thermo-recorders which measured air and wet bulb temperatures were kept out of the sun. 3. 3. Data was recorded constantly for 7 days at 20 min intervals. Plans of houses and furniture arrangement which influence the thermal conditions were drawn from video recordings. Physical and psychological surveys of individuals were carried out over 2 days of daily life. 4. 4. Subjects carried the thermo-recorders (YM1, YM2) on their side. Rectal, back of hand, sole of foot and ambient temperatures were measured every 2 min and with thermistor sensors. At the same time, behaviour and clothes, assessment of thermal sensation, comfort sensation and sensation of estimated room temperature were reported. 5. 5. Thermal radiation was measured with thermographs during the winter. Human activity was recorded every minute for 33 h. This report is the result of surveys in summer and winter. 6. 6. The following results were obtained: (i) the air conditioning is used sometimes in the houses of the elderly; (ii) thermal sensation range reported is narrow; (iii) skin surface temperatures of the elderly are relatively high and their range of change is narrow, and the range of rectal temperature in a day is narrow; (iv) high activity and excessive heating cause a rise of rectal temperature and the rectal temperatures are lower at rest time.

Investigations on the surveys of office environments and the total evaluation method—IAQ-Index

Abstract 1. 1. A comprehensive study was made to establish evaluation methods for better office environments. 2. 2. In our study, measurements of thermal, acoustic, lighting, airflow and air quality conditions in indoor environments were made as well as questionnaire to the occupants on the evaluations of indoor environments and the feeling of fatigue. 3. 3. We also made an attempt to rate the evaluation value based on concepts and standards to evaluate totally office environments in a view point of “the office environments where people can work healthy and vigorously”. The evaluation values were called IAQ-index.