It has been generally accepted that the therapeutic effect of repeating hot spring bathing (base of balneotherapy) consists in alternation and normalization of diseased physiological functions of the body. Endocrine and neural functions act major rolls in these mechanisms. In the present paper, the effects of single bathing in hot and cold water and of long-term repetition of bathing were investigated from endocrinological stand-points. Increased secretion of plasma 11-OHCS was observed by body immersion in cold water (25°C) at 9AM and in hot water (42°C) at 9PM. No change of plasma level of this hormone was seen by cold stimulus at 9PM and heat stress by water immersion at 9AM. These results suggest that there are circadian difference of sensitivity in adrenocortical function to thermal stimuli by water immersion. Both plasma prolactin and renin activity increased by hot water immersion in contrast, cold stimulus caused the suppressive responses in both hormones. It can be postulated that other mechanism(s) than the sensitivity of endocrine gland may be involved in these responses.
In order to investigate the effect of long-term balneotherapy on endocrine function, the change in circadian rhythm of plasma 11-OHCS was measured at 1 week interval in hospitalized patients. In general, diminishing in the amplitude and lowering of peak value were observed 3-4 weeks after starting of balneotherapy. Plasma cortisol level was measured at 7AM everyday during hospitalization for 28 days. The results showed that the possible existence of circaseptan rhythm of cortisol secretion by balneotherapy. Daily fluctuation became smaller approximately 3 weeks after the begining of therapy.
Circadian rhythm of plasma cyclic AMP and cyclic GMP were measured to investigate the effect of balneotherapy on the state of autonomic nervous system. Although marked individual difference in the circadian rhythm of cyclic nucleotides was observed before balneotherapy, common and definite tendency of the rhythm was obtained approximately 4 weeks after starting of balneotherapy.
These results suggests that normalization effect of balneotherapy can be reached 3-4 weeks after starting of therapy from the view-point of endocrine and autonomic nervous functions.

Stellate ganglion radiation by polarized light (SGR) and placebo radiation were applied to healthy adults to compare the effects on the autonomic nervous system and electroencephalogram (EEG) of these radiations and the following results were obtained:
(1) The pulse rate tended to decrease during and after both SGR and placebo radiation. In contrast, the systolic blood pressure tended to increase during and after both radiations. No significant difference between radiations was found in either the pulse rate or systolic blood pressure. The coefficient of variation of the pulse rate (CV-PR), which reflects conditon of the cardiovascular parasympathetic nervous function, tended to increase during and after SGR and tended to decrease during placebo radiation. The value of CV-PR was significantly higher after SGR than after placebo radiation.
(2) The surface skin temperature of the lower extremities after SGR was slightly higher than that after placebo radiation, but the temperature of the upper extremities did not show any difference between SGR and placebo radiation.
(3) The relative power of alpha-2 wave as determined by quantitative EEG tended to be greater during and after SGR than during and after placebo radiation. The value 10min after SGR was significantly higher than after placebo radiation.
These results suggested that SGR activated the cardiovascular parasympathetic nervous function and relatively suppressed the cardiovascular sympathetic nervous function. We concluded that SGR influences not only the cardiovascular autonomic nervous system and surface skin temperature of the lower extremities, but also a wide range of EEG.