Effects of bedtime mouthwash use on sleep: A field sleep study using wristwatch‐type heart rate monitoring devise

Abstract

AbstractThis study aimed to test the efficacy of a mint‐flavored mouthwash when it is used at bedtime for subsequent sleep in a field study setting, using a wristwatch‐type heart rate (HR) monitoring devise. Using a within‐subject experimental design, twenty healthy adults used three types of mouthwash having a different intensity of mint sensation (or water as a control) per one experiment night just before going to bed at their home environment, in a counterbalanced order. As for results, irrespective of the intensity of mint‐flavored mouthwashes, the subjective score for “fatigue” and “refreshing” before sleep was decreased and increased, respectively. In addition, although a significant inhibition of HR decline in the sleep initiation period (0–30 min after bedtime) was observed with the use of mint‐flavored mouthwashes compared with the control, the trend reversed subsequently as HR trended lower than for the control during 2–6 h after the bedtime. These findings suggest that the using mint‐flavored mouthwashes at bedtime induces a positive mood before sleep and may improve physiological sleep. Moreover, this study illustrated the possible application and significant advantage of the use of wristwatch‐type HR monitoring devise in a context of field study.