The effects of bathing in a CO₂-containing bathing solution (Solution A; CO₂ concentration 100 ppm) on summertime indefinite complaints such as fatigue and poor circulation were evaluated. The subjects were 16 females (mean age 40.8 years) who visited the outpatient clinic of the department of gynecology, MINAMITAMA Hospital due to fatigue, poor circulation, and insomnia in summer. After the use of Solution A for 2 weeks, slightly to marked overall improvements were observed in 13 patients, and significant alleviation was noted in fatigue and poor circulation. A questionnaire conducted after the 2-week treatment period showed effects such as relief from fatigue and relaxation as well as hands and feet warmth. No adverse effect was observed, and the rating of usefulness was slightly to marked useful in 14 of the 16 patients. When 6 patients bathed in Solution A and 4 patients bathed in placebo solution (Solution B) for the following 2 weeks, the effects of bathing were reduced in those who bathed in Solution B. These results suggest that bathing in a CO₂-containing solution is a simple and side-effect-free ancillary therapy for summertime indefinite complaints such as fatigue and poor circulation.

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This study covers research on the simultaneous measurement of NO₂ concentration conducted at 195 sites in the Ise Bay area of Mie, Aichi, and Gifu prefectures. The research was conducted over two seasons, winter of 1997 (January 16th-17th) and summer of 1998 (July 15th-16th). Due to our grasp of the wind trajectory and the area of divergence, we were able to analyze the effects of land and sea breezes on the source of pollution, transportation, stagnation, and geographic features (topography). The area of divergence is closely related to the topography and sea breezes. In the Ise Bay area the sea breezes diverge at the base of inland mountainous areas. In short, we now understand that the divergence area is created between the valleys and the bottom of the inland mountainous areas that serve as the pathway for the inland penetration of the sea breezes. In addition to the Ise Bay area, we also have a good grasp of the area of divergence covering Mie Prefecture from the Ise Plain to the Suzuka Mountain Range, Nobi Plain, Yoro Mountains, Ibuki Mountains, Minomikawa High Lands. The research shows that areas with a high concentration of NO₂ pollution include Nagoya City, Yokkaichi City, Kuwana City, Kagamigahara City and Tajimi City. According to the analysis of the wind trajectory and our calculation of divergence by Tanaka and Milkovich method, we were able to estimate the source of the pollution, transport route, and the area of stagnation. The reason for the high concentration of pollution in Kagamigahara City and Tajimi City, which are not big cities or industrial areas, is that Kagamigahara City is in the path of the Southwest winds from Yokkaichi City and Kuwana City, while Tajimi City is in the path of the South-south-west wind from Yokkaichi City and Kuwana City, that passes through Nagoya City. The evening and midnight to early morning winds that blow through the cities, industrial areas, and roads are carried by the sea breezes, and delivered to the inland areas. Daytime winds carry less pollution, while at night, Yokkaichi City produces NO₂, and that NO₂ is carried on the winds to be deposited at the divergence spots where the winds stagnate.

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Several studies have reported a “V”-shaped relationship between short-term temperature and mortality rates, characterized by mortality rates that are higher when temperature is extremely low or high than when moderate. To quantify the confounding effect of humidity on the V-shaped short-term temperature-mortality relationship, we studied Japanese prefecture-specific data from 1972 to 1990. We classified the prefectures into 5 areas according to the 19-year mean temperature. For each area, we calculated all-cause mortality rates of 65+ years old subjects by gender, year, daily maximum temperature and daily relative humidity. We then calculated two types of Mantel-Haenszel rate ratios: one controlled for year only (MHRRy), and the other controlled for year and daily relative humidity (MHRRyh). The ratio of MHRRy to MHRRyh would be unity, if humidity were not a confounder. This ratio (MHRRy/MHRRyh) by daily maximum temperature, area and gender ranged from 0.989 to 1.037, and 89% of the ratios was between 0.990 and 1.010, i.e., the discrepancy was less than 1%. This suggests that we need not control for humidity in evaluating the short-term temperature effect on all-cause mortality, at least for 65+ years old age group in Japan.

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The aim of this experiment is to gain data for making use of thalassotherapy in preserving and improving health. We investigated the effects of various salt concentrations on ECG findings during and after bathing in a salt water. The subjects were 6 healthy young males. At set times for four consecutive days the subjects bathed in the following water conditions: plain water; 1%, 3.5%, and 7% salt water concentrations. At the beginning of bathing, the temperature of the water was set at 38.20∼38.33°C in each salt water concentration. The subjects bathed for 15 minutes and then rested in a chair for 30 minutes. While bathing, the mean heart rate of the subjects in all four conditions increased significantly. However, after bathing, a significant increase of heart rate was observed only in the 7% salt water bath during first 4-7 minutes. A significant decrease was found in the mean CV_R-R in all of the salt water bathing, but after bathing, a significant decrease was found only in the 7% salt water bath. It was also observed that the mean LF/HF in the 1% salt water bath increased significantly during an 11-14 minute bathing period. The above results show that salt water bathing, especially that in a concentration of 7%, has a greater influence on the cardiovascular system and the autonomic nervous system than plain water bathing.

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