A few hours of forest walking (shinrin-yoku) has been reported to have both physiological and psychological efficacy for health promotion. The aim of this research was to examine through a cross-sectional study of the relationship between the frequency of forest walking and health status, and to compare forest walking with other health practices to investigate its long-term efficacy. The outcome variables were self-rated health status, subjective mental stress, and self-reported lifestyle disease (hypertension, heart disease, diabetes mellitus, or hyperlipidemia). Participants were healthy volunteers who visited The University of Tokyo’s University Forest in Chiba on two different days in April, 2001, and the Kyoto University Forest in Ashiu on two different days in November, 2001. A total of 279 participants were included in the analyses. They were classified into 4 categories according to the frequency of forest walking. Results showed that higher frequency of forest walking was significantly associated with both higher ratios of good self-rated health and lower ratios of poor self-rated health. The highest frquency forest walking group showed the highest ratio of low psychological stress as well as the lowest ratio of high psychological stress, this was not statistically significant, however. No association was found between the frequency of forest walking and the lifestyle disease morbidity. These results suggest that the frequency of forest walking is related to health status. The efficacy of forest waking, however, should be further explored because the current cross-sectional study could not address a causal relationship.

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The purpose of this study is to evaluate empirically and theoretically the solar-shading effect of traditional pine hedges in Izumo Plain, called “tsuijimatsu”. The geometries of forty-five pine hedges were measured. The observation of the illuminances at 15 points with tsuijimatsu, 11 points with copse, and 20 points with no tsuijimatsu/copse showed little significant differences of daylight factors/shading ratio of daylight illuminances at between tsuijimatsu and copse points. Solar radiation, outdoor temperature, outdoor and indoor wall surface temperatures, and indoor air temperature at two houses with and without tsuijimatsu were also observed. The tsuijimatsu intercepted mostly the solar irradiation and lowered obviously outdoor, wall surface, and indoor temperatures. The estimations of solar irradiation passed through tsuijimatsu was in agreement with the measured value. The shading ratio of solar irradiation which was derived from the geometries of forty-five pine hedges was more than 80%.

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In living spaces, a floor sitting posture with much of the surface of the body in contact with the floor or a lying down position is taken, and in the case where the temperature of the spatial structure in contact with the human body or the surface temperature of the object is not equivalent to the air temperature, the effect of this is difficult to disregard. Accordingly, it is necessary to include not only air temperature but also thermal radiation, wind speed, humidity and heat conduction in considering the thermal sense of humans. The purpose of this paper is to propose the sensational temperature index in order to make possible the evaluation of thermal environments that consider behavioral thermoregulation and to verify this index, which express the influence of thermal environment upon the human body, by experimental data. Conduction corrected modified effective temperature, ETF, which is a new thermal environmental evaluation index incorporating heat conduction, was defined. It was explained that ETF is a thermal environmental index that converts wind speed, thermal radiation, humidity and heat conduction into temperature and is capable of additive expression independent of air temperature. And ETF is a thermal environment index that comprehensively expresses the effect of air temperature, wind speed, thermal radiation, humidity and heat conduction. Through use of ETF, it is possible to represent and quantify the composite influence on bodily sensation and the effects of discrete meteorological elements through evaluation on an identical axis. ETF has a strong relationship with mean skin temperature and has been demonstrated to be an effective thermal environmental evaluation index. Use of posture condition parameters has confirmed a good correspondence relationship between ETF and thermal sense and is also beneficial as a thermal environmental index. ETF will make possible to draw up specific control values of environmental factors. In addition, it will make it possible to express environmental control activities in sensational temperature.

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In previous studies based on the heat balance theory, we derived two formulae that expressed the heat balance equation of the human body standardized by skin temperature, in terms of the wet bulb temperature T_w, black globe temperature T_g, and air temperature T_a. On the basis of these formulae, we introduced WBGT* as a new thermal index. The WBGT* is of the same form as the original WBGT formulae empirically established by Yaglou et al. The differences between these two sets of formulae are as follows:
1. The WBGT* for an environment devoid of solar radiation, WBGT*=0.85T_w+0.20T_g, is different from the original WBGT proposed by Yaglou et al., WBGT=0.7T_w+0.3T_g, in terms of the coefficients.
2. The WBGT* for an environment with solar radiation is WBGT*=0.84T_w+0.30T_g−0.08T_a; the WBGT derived by Yaglou et al. is WBGT=0.7T_w+0.2T_g+0.1T_a. The WBGT* is characterized by a negative coefficient of T_a.
The purpose of the present study was to examine the significance of the difference between the WBGT derived by Yaglou et al. and the WBGT* introduced by us and to interpret the thermophysical meaning of the negative coefficient of T_a in the WBGT*. The following conclusions were drawn:
1. In the case of a highly humid environment, the difference between the values calculated using Yaglou’s WBGT and our WBGT* was found to be 1.5°C. This difference corresponds to a difference of almost 4∼5°C in the air temperature. Thus, in a humid environment, the values obtained by using Yaglou’s WBGT are less than those obtained by using our WBGT*.
2. The negative coefficient of T_a can be explained in terms of the difference between the operative temperature of humans and T_g and the negative correlation between T_a and the environmental water vapor pressure P_a at a constant T_w. This negative correlation indicates that for a constant T_w, an increase in T_a leads to a decrease in P_a.

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On the basis of our previous papers, a method was developed for estimating the clo values of clothes worn by the subjects in photographs taken by a fixed point observation field survey. In order to obtain information about hidden garments from the appearance of each subject in the photograph, questionnaires were given to 80 males and 150 females in each season, asking them to describe the clothes that they would most likely wear under the garments shown in the photographs. In addition, at list containing the clo value of each garment was compiled after referring to the clo values reported in ISO/DIS9920 and Hanada (1992). The clo value for each subject in the photographs was calculated by adding the clo value of each garment worn by the subject. As a result, the average clo value for males was larger than that for females throughout the year, while the clo value for both groups correlated highly with the average daily air temperature, in accordance with the results reported by other researchers previously. The relationship between the predicted clo value and the ambient temperature was overlapped the comfort zone by SET* except when the ambient temperature was over 27°C. In the zone over 27°C, the clo values for males predicted were higher than the zone obtained the equation due to the social restraint for fashion in Japanese society. The validity of the method for estimating the clo value through a fixed point observation field survey was confirmed in this paper.

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To analyze the relationship between heat extraction (HE), skin temperature, skin blood flow (SkBF), and changes in core temperature responses wearing water perfused suits (WPS) during exercise, seven male subjects performed 40-min of steady exercise at light intensity (250 W/m²) in a room maintained at 30°C. Esophageal (Tes), deep thigh (T-d.thigh), and mean skin temperature (Tsk), SkBF at forearm and chest, heart rate (HR), and total sweat loss (TSL) were measured under six condition, with two sets of clothing, semi-nude (NU) and WPS perfused water at 18 (W18), 24 (W24), 30 (W30), 32.5 (W32.5), and 35°C (W35). The HE was calculated the differences in water temperatures between inlet and outlet in WPS. The Tes, T-d.thigh, HR, and TSL at the end of exercise were similar between NU and W24, and those were higher in W32.5 and W35 than in NU. Under W30, 32.5, and 35 conditions, increase in SkBF in response to a raise in Tes (⊿Tes) attenuated when ⊿Tes exceeded 0.3°C. Under W18, 24, and NU conditions, however, the ⊿Tes remained constant at 0.3°C according to the increase in SkBF. In addition, ⊿Tes at the end of exercise markedly elevated when Tsk exceeded 35.5°C and HE less than 125 W. Under WPS condition, HE negatively correlated significantly to the changes in Tsk (⊿Tsk, r=−0.856, p<0.001), or T-d.thigh (⊿T-d.thigh, r=−0.807, p<0.001) from resting levels and also correlated to the ⊿Tsk multiplied by SkBF (⊿Tsk×SkBF, r=−0.857, p<0.001) as an index of flow and temperature in peripheral venous blood. The ⊿Tes remained constant when ⊿Tsk×SkBF became negative, while ⊿Tes markedly increased when positive values of ⊿Tsk×SkBF was observed at the end of exercise. These results suggested that a critical level of HE, Tsk, and ⊿Tsk×SkBF inducing an attenuation of ⊿Tes does exist during low intensity steady exercise under the different water temperature conditions wearing WPS, and those were related to the peripheral venous blood flow and its temperatures.

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