BACKGROUND
Poor sleep quality and daytime sleepiness can hinder work efficiency and adversely affect well-being. Sleep quality can be objectively assessed by wearable devices, and daytime sleepiness and mental state can be timely ascertained from by ecological momentary assessment (EMA); however, few studies have been conducted using a combination of all of these tools.
OBJECTIVE
The aim of this study was to explore the association between physiological data, such as sleep time and heart rate variability (HRV), measured objectively by wearable devices, and sleepiness, mood, and vitality status measured by EMA and use of rating scales for stress/well-being.
METHODS
A total of 40 office workers (mean age, 40.4 years; SD, 11.8 years) participated in the study. Their stress levels and perception of well-being (hereinafter, stress/well-being) were assessed at the beginning of the study. Then, they were asked to wear a wearable wristband device (Fitbit Inspire 2 from Fitbit Inc.) during the day for 8 consecutive weeks. EMA on sleepiness, mood, and vitality was conducted through email messages sent by the subjects four times a day, each three hours apart, on eight designated days during the 8-week period. After the device-wearing period of 8 weeks, the stress/well-being of the workers were assessed again. Subjects were divided into quartiles based on the assessed scores, and the sleep indices measured by the Fitbit were compared between the groups with values in the lowest quartile and highest quartile.
RESULTS
The total response rate for the EMA was 87.3%, and the total Fitbit wear rate was 88.0%. Groups with higher subjective stress went to bed significantly later than the group with lower subjective stress (p=0.0001). The group with higher scores on well-being showed statistically smaller weekly standard deviations of the midpoint of sleep as compared with the group with lower scores on well-being (P-values: <0.0001).
CONCLUSIONS
This study, which utilized both wearable devices and EMA, was well-received by the participants. Some relationships were found between objective sleep indicators and the stress/well-being of the subjects. Future research utilizing these methods focused on specific targets, for example, social jet lag, could provide further useful insights.
CLINICALTRIAL
UMIN-CTR UMIN000046858 https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000053392