1) The effects of a single bath in the radioactive hot spring on the blood pressure and the pulse rate. The author observed the changes of the blood pressure and the pulse rate of subjects bathing for 20 minutes, 39°± 1°C, in temperature, in the radioactive hot spring in Misasa. It may be summerized as follows (Table 2, Fig. 1). a. In the hypertensive group (maximal blood pressure······181 mm. Hg. and over), the maximal blood pressure had decreased immediately after bathing, and remained at this level even 2 hours after bathing. The minimal blood pressure reacted in the same manner as the maximal blood pressure. b. The moderate hypertensive group (maximal blood pressure······180-161 mm. Hg.). In a few instances, the maximal blood pressure had increased immediately after bathing, but decreased within 30-90 minutes after bathing. Changes in the minimal blood pressure were not so remarkable. c. In the normal group (maximal blood pressure······160～101 mm. Hg.), the maximal blood pressure had lowered within 30-90 minutes after the radioactive hot spring bathing. The minimal blood pressure showed no significant changes. b. The pulse rate had increased immediately after bathing in all groups, but within 30 minntes had returned to the initial rate and there were no further changes for 2 hours (Table 2, Fig. 2). 2) The effects of a radioactive vapour bath on the blood pressure and the pulse rate. After a bathing in vapour bath (10～15 minutes), the maximal and the minimal
blood pressure showed mild decrease for 2 hours. The changes of the pulse rate and the pulse amplitude were not so remarkable (Table 3, Fig. 3). 3) The effects of a series of baths in the radioactive spring on the blood pressure. The author observed the changes in the blood pressure of the subjects bathed 2 or 3 times daily in the radioactive hot spring in Misasa, at a temperature of 42～43°C., 5～10 minutes. The blood pressure of subjects was measured once a day (at 7 a.m.) for the first week, and subsequently once weekly for two additional weeks. Subjects with an initial maximal blood pressure over 160 mm. Hg. showed a fall on the second day of the spa treatment followed by a temporary rise on the 3rd or 4th day, after which the pressure fell to the 2nd day level again, and then remained fairly constant to the end of the observation period. Subjects with an initial blood
pressure under 159 mm. Hg. also showed a fall in the course of the spa treatment, but the degree of the fall was slighter than that of the former (Table 4, Fig. 4). This tendency was also observed on the out-patients (Table 5, Fig. 5). The changes of the blood pressure and pulse rate of subjects after a bath for 20 minutes, in water 39±1°C. in temperature, on the first day of the spa therapy were compared with those occuring on the 6th or 7th day, and it was observed that the patterns of the changes in blood pressure following bathing on the two days were significantly different (i.e. on the latter, so called "the initial blood pressure increase following the bathing" was not observed) (Table 6,7,8, Fig.6,7,8,9,). 4) The remote investigation on the spa visitors with hypertension and/or arteriosclerosis. The author investigated the course of patients with hypertension and/or arteriosclerosis who received the spa treatment at Misasa after returned to home. The incidence of subjects who answered as being good was 86%, and it was observed the fall of the maximal and the minimal blood pressure, especially the fall was remakable in subjects who stayed at spa about 4 weeks (Table 10, 11, 12, 13, 14, 15, Fig. 10). 5) The incidence of hypertension among the residents in the spa resort and those residing in other places. The author measured the blood presssre of the out-patients of his institute over
41 years of age from June, 1956 to May, 1957. The incidence of patients with the maximal blood pressure over 160 mm. Hg. was 16.4% in spa resort, and 25.7% in places where there are no hot springs. Using x(2)-test, the difference between the two was recognised as being significant (Table 16, 18). 6) Comparison of the mortality rate of patients with hypertension between residents in the spa resort and those residing in other places. The author examined the mortality rate of persons with hypertension in the area under the jurisdiction of the Kurayoshi Sanitary Institute, Tottori prefecture, from 1954 to 1956. The rate of mortality in the spa resort was 17.5% as compared to 21.4% in other places (Table17).