Effects of thermal stimulation in the stone spa on physiological responses

To clarify the effects of the thermal stimulation on physiological responses, we evaluated the temperature, circulatory, hematological and immunological changes in 11 healthy female volunteers before and after taking a stone spa (about 41°C). The subjects took the 15 min stone spa three times with 10min resting intervals, either in the daytime, or in the nighttime. Compared with the baseline value before the stone spas, body temperatures of the depths such as the tympanum and surface temperatures such as the palm, upper hand, and thigh, abruptly increased after the first stone spa, and then maintained it with a gradual increase after the second and third stone spa. Heart rate and PRP gradually increased while blood pressure remained unchanged. Blood glucose concentration after stone spa was lower than before it in the nighttime, but no significant changes. Blood lactic acid concentration after stone spa showed lower levels, especially at nighttime. The rate of lymph cell after stone spa was higher than that before it. Conversely, the rate of granule cell after stone spa was lower than that before it. NK cell activities, measured only in the daytime, tended to increase after a stone spa, but not at significant levels. From the present results it became apparent that the stone spa could easily change the rate of leukocyte in contrast to NK cell activities. These results may suggest that these changes were possibly induced through modulating autonomic nervous functions. [J Physiol Sci. 2007;57 Suppl:S180]