Effects of Room Temperature on Physiological and Subjective Responses during Whole-body Bathing, Half-body Bathing and Showering

Abstract

The effects of bathroom thermal conditions on physiological and subjective responses were evaluated before, during, and after whole-body bath (W-bath), half-body bath (H-bath) and showering. The air temperature of the dressing room and bathroom was controlled at 10°C, 17.5°C, and 25°C. Eight healthy males bathed for 10 min under nine conditions on separate days. The water temperature of the bathtub and shower was controlled at 40°C and 41°C, respectively. Rectal temperature (Tre), mean skin temperature (Tsk), blood pressure (BP), heart rate (HR), body weight loss and blood characteristics (hematocrit: Hct, hemoglobin: Hb) were evaluated. Also, thermal sensation (TS), thermal comfort (TC) and thermal acceptability (TA) were recorded.
BP decreased rapidly during W-bath and H-bath compared to showering. HR during W-bath was significantly higher than for H-bath and showering (p<0.01). The double products due to W-bath during bathing were also greater than for H-bath and showering (p<0.05). There were no distinct differences in Hct and Hb among the nine conditions. However, significant differences in body weight loss were observed among the bathing methods: W-bath>H-bath>showering (p<0.001). W-bath showed the largest increase in Tre and Tsk, followed by H-bath, and showering. Significant differences in Tre after bathing among the room temperatures were found only at H-bath. The changes in Tre after bathing for H-bath at 25°C were similar to those for W-bath at 17.5°C and 10°C. TS and TC after bathing significantly differed for the three bathing methods at 17.5°C and 10°C (TS: p<0.01 TC: p<0.001). Especially, for showering, the largest number of subjects felt “cold” and “uncomfortable”. Even though all of the subjects could accept the 10°C condition after W-bath, such conditions were intolerable to half of them after showering.
These results suggested that the physiological strains during H-bath and showering were smaller than during W-bath. However, colder room temperatures made it more difficult to retain body warmth after H-bath and created thermal discomfort after showering. It is particularly important for H-bath and showering to maintain an acceptable temperature in the dressing room and bathroom, in order to bathe comfortably and ensure warmth.