Effect of carbon dioxide bath on cardiovascular functions and peripheral circulation were studied using a new system of carbon dioxide bath. The subjects consisted of 13 males and 17 females, ranging from 50 to 84 years old, 67.4±8.3 in average, having the complaints resulting mainly from arteriosclerosis such as coldness on extremities or exertional pains of lower extremities. Each subject took a bath in plain water (PW) on the first experimental day and then a bath in carbon dioxide (CO₂) at the same time on the second experimental day. Both baths were done for 10min. at 39°C of water temperature. The results obtained were as follows.
1) Mean blood pressure (MBP) was elevating during bath and lowered below prebath level immediately after bath in both PW and CO₂ groups. However, MBP in CO₂ group was lower significantly (p<0.05) than in PW group 20 and 30min after bath.
2) Both body and skin temperatures were similarly elevated at all points to be measured directly after bath, and then lowerd gradually thereafter. There was no significance in changes between both groups.
4) An increase in cutaneous blood flow was observed at the same grade in both groups during and after bath, though no showing significant difference between both groups.
5) PO₂ in venous blood increased after bath, while PCO₂ decreased. However, no significant difference in these changes was observed between both groups.
6) Tendency to increase in CV R-R was observed during and after bath, though no significant difference was showed between both groups.
7) Relating to the feeling to bath, all subjects had the feeling of “warmness” at the beginning of bath and also of comfortableness during and after bath in both PW and CO₂ groups. However, there was no difference in the intensity of these feelings between both groups.
8) No side reaction due to an inhalation of carbon dioxide during bath was observed in all subjects.
From these results, it is expected that a new carbon dioxide bath results in benefit for patients with disturbance of peripheral circulation.

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.