A total of 422 patients who were hospitalized in the Division of Rehabilitation, Kusatsu Branch Hospital of the Gunma University Hospital from 1986 to 1996 was analysed with respect to the patients' sex, age, place of residence, disease, complications, day from onset to admission to our hospital, days of treatment in the hospital, outcome, reason to receive rehabilitation, persons who took care of the patient, and family members. Of the 422 cases, 262 (62.1%) were 65 or more years old. 193 patients (45.7%) were residents of Kusatsu, and 143 patients (33.9%) were from outside Gunma Prefecture.
With respect to diseases, cerebral diseases had the highest percentage (148 cases, 35.1%) and 277 (65.6%) cases had complications. The mean days of treatment in the hospital were 73 days. Hot-spring bathing was used for rehabilitation in 351 (83.2%) cases, resulting in improvement of clinical symptoms and quality of life in almost all cases. As to reason to receive rehabilitation in our hospital, 202 (47.9%) came of own will, 79 (18.7%) were recommended by doctors of other hospitals, and 68 (16.1%) were emergency admissions. Most patients lived alone or had only one family member of an old age and 83.2% of the persons who took care of patients were female family members. Many patients still wanted to receive rehabilitation even long after the onset of their impairment. These findings suggest that hot-spring bathing is effective for rehabilitation of various kinds of diseases. Although it has been found that many patients came to our hospital from various areas in the country expecting to rehabilitation using hot-spring water, it is difficult to follow up on them and to contact their family members for instructions.

A 3-min bath in 47°C hot-spring water called ‘jikan-yu’ has been recommended for over 130 years at Kusatsu-spa. There is a traditional custom of pouring hot-spring water of the same temperature over the head before entering the bath to avert an afflux of blood to the brain. The medical significance of this custom was investigated in 8 healthy male volunteers (age 31±6 years and body mass index 22.4±1.6kg/m²). There were no significant differences in plasma levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), cortisol, and β-endorphin on a comparison of findings before and after the action of pouring 20 pails of 47°C hot-spring water over the parietal and occipital areas of the head. However, the direct effect of heat stress on the internal thermosensor in the anterior hypothalamus regulating heat loss and thermogenesis was not examined in this study. Thus, it is considered that the action does not provide a direct hyperthermal stimulus to the brain stem to release stress hormones but may dilate blood vessels of the head to prepare for the abrupt afflux into the cerebral circulation of blood heated by subsequent very hot hot-spring bathing.

We have investigated change in platelets and the blood coagulation and fibrinolytic systems as a mechanism of the onset of thrombotic diseases during and after hot-spring bathing. In this study, We examined effect of 10min 42°C and 37°C hot-spring bathing on protein C, protein S and antithrombin III in seven healthy male subjects. The mean values of protein C antigen, protein C activity, total and fee protein S antigens, protein S activity and antithrombin III activity were slightly increased by both methods, while these changes were not statistically significant. Taken together with our previous reports, 10min 42°C hot-spring bathing gives no effect on the blood coagulation system.

From March 1990 to September 2001, 24 patients with psoriasis (16 males and 8 females, 54±18 years) were admitted to our hospital to receive balneotherapy using Kusatsu hot-spring water. The psoriasis had been refractory to various treatments including steroid ointment therapy over a long period of time. The patients took a 10-minute 40-42°C hot-spring bath followed by application of vitamine D3 ointment 1-2 times daily for 37±19 days. The main components of the hot-spring water are aluminium, sulphates and chlorides, and its pH is 2.0. The skin symptoms of 20 of 24 cases (83%) were improved through the balneotherapy, while those of the remaining 4 cases were not changed. No side effects were observed. The serum levels of uric acid, GOT and GPT which are reported to be increased slightly did not correlate with the skin symptoms. The serum LDH level which is associated with the skin manifestastions in patients with atopic dermatitis also gave no useful information in the treatment of psoriasis. Although the mechanism of the improvement of skin manifestations is not clarified, balneotherapy at Kusatsu can be useful for the treatment of refractory cases of psoriasis as alternative and complementary medicine

A patient with atopic dermatitis who presented muscular weakness of lower extrimities and tetany due to severe hypokalemia, hypocalcemia and hypomagnemia was described. The hypokalemia and hypomagnemia were caused by pseudo-Bartter's syndrome due to persistent dehydration, and the hypocalcemia was caused by pseudohypoparathyroidism due to hypomagnemia. The persistent dehydration was considered to be resulted from long-term and long-time bathing. Thus, adequate supply of water and electrolytes may be necessary in long-term balneotherapy.