Studies on the effects of heating as well as the mineral components of hot spring water have been conducted to investigate the effects of balneotherapy. However, few studies have been conducted on the effects of hydrostatic pressure and buoyancy during water immersion. Therefore, we investigated the effect of water immersion up to the neck at thermoneutral temperature on hemostatic activity.
Nine healthy men aged 22 to 34 were immersed up to the neck in the standing position in thermoneutral water (34.0±0.5°C) for two hours. The heart rate decreased immediately after starting water immersion and remained low during the immersion. Hematocrit values (Ht) of the blood samples taken from the ante-cubital vein decreased by 3.4% in average. The decrease in Ht was more prominent in the blood samples taken from the earlobe (4.0%), suggesting that hemodilution due to fluid shift was stronger in the upper part of the body. The time until euglobulin clot lysis shortened immediately after starting the immersion. Although fibrinolytic activity was enhanced, the concentration of tissue plasminogen activator (t-PA) antigen in the blood decreased gradually during the immersion and tended to return to the original level 30 minutes after immersion. A larger decrease in the concentration of plasminogen activator inhibitor-1 (PAI-1) antigen in the blood was observed immediately after starting the immersion, and it remained low for 30 minutes after immersion. An increase in fibrinolytic activity due to the decrease in PAI-1, not in t-PA, was observed during water immersion at thermoneutral temperature and the activation of fibrinolytic system without activation of the coaguration system was also observed.

In order to study the physical fitness of rural children in Gifu prefecture, a total of 128 rural boys and girls aged 8-14 years old in the Tokuyama-Elementary School and-Middle School, which are in a far rural district from busy civilized urban distriet, were measured for the developmental status, i. e, physique, examination of physical fitness, maximum working capacity, cardiorespiratory function and urinary excretion in summer, 1962, and the comparison was made on the results obtained there with those of the average Japanese children of the same age.
The results obtained were as follows:
1) Little or no difference was found between physical development of rural children and that of average Japanese boys and girls ; i. e, the physique of rural children was not superior nor inferior to the value of the average Japanese children.
2) The record of sprint games, such as 50m-sprint-run, broad jumping, ball throwing, Sargent-jump, grip strength and back strength of rural children was lower than that of the Japanese average. Whereas, the endurance ability measured with a long-distance running (1500m for boys and 1000m for girls) was tended to be higher in the rural children, especially in the girls, than the average Japanese value. However, no significant difference was presented in the flexibility test (forward bending of the upper-body in standing posture) between rural and average Japanese values.
3) The examination of cardiopulmonary function : i.e. E.C.G., blood pressure, heart rate, vital capacity and maximum expiratony flow rate exhibited no abnormal sign. The systolic and diastolic blood pressure tended to increase with age, but the heart rate tended to decrease. The examination of the urinary glucose, protein and occult-blood remained normal, and most of the urine pH of the girls were within the range between 6 and 7, whereas, those of boys were between 5 and 6.
4) The maximum working capacity (maximum oxygen intake, vital capacity) showeda linear increase proportional to age and physique (body height, body weigmt, body surface, etc, ) over the range of the age tested. Sexual difference appeared after 12 years of age.
5) The possibility was suggested that the maximum O₂ intake could be predicted from the vital capacity of the same individual regardless of age, sex and physique, and a theoretical background for that was discussed.

Effects of 38°C 30-minute bathing on hemostatic function and autonomic nervous function were studied in 15 48-to-72-year-old patients with cerebral infarction. Blood samples were collected three times: immediately before the bathing, at the end of 30 minutes of bathing, and 30 minutes after the bathing. Hematocrit values and fibrinogen concentrations decreased during bathing and returned to the pre-bathing levels 30 minutes after bathing. This indicates that bathing caused hemodilution due to the fluid shift. During bathing, noradrenaline decreased at a rate significantly higher than that of hemodilution while the sympathetic nervous function, which was evaluated by spectral analysis of sequential variation in arterial blood pressure, was not suppressed. The autonomic nervous system seemed to be inactive in these patients. Coagulation time (PT and APTT) and platelet factor (β-TG and PF4) showed few changes. In the fibrinolytic system, however, tissue plasminogen activator (t-PA) antigen levels increased and plasminogen activator inhibitor type-1 (PAI-1) levels decreased after 30 minutes of bathing. This suggests that fibrinolytic activity was enhanced by 38°C bathing for 30 minutes. Thus, subthermal bathing with comfort may be useful in preventing cerebral infarction.