This 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.

中文翻译：

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睡前漱口水对睡眠的影响：使用手表式心率监测设备进行的现场睡眠研究

本研究旨在通过现场研究环境，使用手表式心率 (HR) 监测设备，测试在睡前使用薄荷味漱口水以促进后续睡眠的功效。采用受试者内实验设计，二十名健康成年人在每个实验晚上临睡前在其家庭环境中以平衡顺序使用三种具有不同薄荷感觉强度的漱口水（或水作为对照）。结果显示，无论薄荷味漱口水的强度如何，睡前“疲劳”和“清爽”的主观评分分别下降和上升。此外，尽管与对照组相比，使用薄荷味漱口水可以显着抑制睡眠开始阶段（就寝后 0-30 分钟）的 HR 下降，但 随后趋势发生逆转，睡前 2-6 小时内 HR 趋势低于对照组。这些发现表明，睡前使用薄荷味漱口水可以在睡前产生积极的情绪，并可能改善生理睡眠。此外，本研究说明了在现场研究中使用手表式心率监测设备的可能应用和显着优势。