The effects of artificial sodium sulfate bathing on cardiopulmonary and neurohumoral systems as compared to plain water bathing were studied on five healthy subjects. The results of bathing tests made for 10 minutes at 42°C were as follows:
1) The body surface temperature was higher in three of the five subjects in artificial sodium sulfate bathing than in plain water bathing. The forehead temperature of all subjects in artificial sodium sulfate bathing was higher than in plain water bathing (p<0.05: at 17, 18min. after bathing). The change in oral temperature also showed the same tendency (p<0.05: at 27min. after bathing).
2) The frequency of respiration was less in artificial sodium sulfate bathing than in plain water bathing. Although the heart rate decreased during artificial sodium sulfate bathing as compared to the case of plain water bathing, a clear difference was not observed after bathing. The systolic blood pressure in four of the five subjects decreased in artificial sodium sulfate bathing compared to plain water bathing. One subject, who exhibited low blood pressure before bathing, was restored to his normal blood pressure after artificial sodium sulfate bathing. The sysytolic blood pressure was lower in artificial sodium sulfate bathing than in plain water bathing. (p<0.03: at 20min. after bathing).
3) The serum levels of noradrenalin, adrenalin, serotonin, ADH, renin, aldoster-one, cortisol, β-endorphine, Na⁺, K⁺, and Cl^- showed no significant differences between the two types of bathing.
4) All subjects felt increased warmth and smoothness of the skin after the artificial sodium sulfate bathing compared to plain water bathing.
The above results suggest that the artificial sodium sulfate bathing is superior to plain water bathing in maintaining body temperature, decreasing blood pressure, and feeling (i. e., body warmth and skin texture) after bathing. These effects result from not only the direct action on the skin but also the indirect action due to absorption of the substance through the skin by the mechanism of artificial sodium sulfate bathing.