ABSTRACT
Physiological effects of local bubbling during bathing have been evaluated from three series of experiments. In the first series, four male subjects bathed for 6 minutes. and their chests were exposed to bubbling at rates of 13, 20 and 45<i>l</i>/min. Water temperature (Tw) was initially controlled to 37 and 42°C, and then adjusted by the subjects to optimum Tw. In the second series, four male subjects bathed in 39°C water. Four sites (chest, back, lower back, and shin) were exposed to bubbling at rates of 8, 13<i>l</i>/min and the rate of 8<i>l</i>/min alternating with the rate of 13<i>l</i>/min at second intervals. In the last series, four male subjects bathed in 39°C water and two sites (chest and lower back) were exposed to bubbling at rates of 13, 33 and 46<i>l</i>/min. Blood pressure, heart rate, rectal and skin temperatures, minute ventilation were monitored on each occasion.<br>Subjectively determined optimum Tw was about 39°C in the case of initial Tw of 37°C, and was 41°C in the case of initial Tw of 42°C. Systolic blood pressure decreased while heart rate and minute ventilation increased during bathing. Physiological variables changed significantly when chest and lower back were exposed to bubbling at the rate of 33<i>l</i>/min. The increase in rectal temperature after bathing is likely proportional to the decrease in skin temperature at the lower extremities. It is, therefore, suggested from these results that local bubbling to chest/back may be most effective when the rate of bubbling is controlled in the range of 20-35<i>l</i>/min at Tw of 39°C.