To find the correlation between the inhibitory effects of hot-spring water on blood-pressure and its chemical composition, the effects of artificial spa bathing on lowering blood pressure were compared with those of hot-spring bathing on spontaneously hypertensive rats (SHR). Further, the induction of heat-shock proteins (HSP) in rat organs was quantitatively examined in order to clarify the mechanism of its action. Artificial spa (Na₂SO₄-Na₂HCO₃) bathing showed almost the same inhibitory effects on blood pressure as those of hot-spring bathing.
There was no significant difference in the catecholamine value in blood between both types of spa bathing, nor was there any difference from the values of the control group.
It was found that HSP molecules were induced in the brain, liver, and kidneys not only by hot-spring bathing but also by artificial spa bathing, with different inductive profiles from one organ to another.