1-8 The Effect of Bathwater Additive on Arousal Level

Our study aims to investigate the effect of bathwater additive on arousal level after bath, Healthy university/graduate students (n=8) participated to the experiment in laboratory for three days. Participants bathed for 5min from CT15. We set three bathing conditions; bathe 1) without additive, 2) with an additive having aroma of citrus (NBC-KP-Yuzu), 3) with an additive having aroma of forests (NBC-KP-Shinryoku). Aromatic bathwater additives which dissolve and diffuse quickly (Tsumura Lifescience Co., Ltd.) were used. Twenty-minutes testing sessions were held at CT14.5, immediately after bath and 30min after. Subjective sleepiness (KSS) and condition (VAS), Psychomotor Vigilance Task (PVT) and HRV by ECG were measured. Heart sympathetic nerve activity index (LF/HF in HRV) (p＜.05), correct level of PVT (p＜.05) and alertness (p＜.001) with conditions 2&3 were significantly indicated. Results showed that bath with the additives having aroma which dissolve and diffuse quickly prevent decrease of arousal level and keep one active mentally and physically after bath.