Just-in-time Adaptive Intervention for Stabilising Sleep Hours of Japanese Office Workers: A Micro-randomised Trial

Abstract Sleep disturbance is a major contributor to future health and occupational issues. Mobile health (mHealth) can provide interventions that address adverse health behaviours for individuals in vulnerable health state, in real-world settings (just-in-time adaptive intervention, JITAI). Here, Japanese office workers were instructed to collect data on their habitual sleep behaviours (including sleep hours, midpoint of sleep, and sleep efficiency) and momentary symptoms (including depressive mood, anxiety, and subjective sleep quality) using digital devices in a real-world setting. In study 1, we utilised these data to identify a subpopulation that had problems in habitual sleep behaviours and found that unstable sleep hours were associated with disturbed momentary symptoms. Based on these findings, in study 2, we designed and conducted a sleep JITAI, which delivered objective push-type sleep feedback for stabilising their sleep hours, for some participants in study 1. Moreover, we employed micro-randomisation to examine the within-individual proximal effects of the intervention. Providing sleep feedback prolonged subsequent sleep hours, but this effect was attenuated over time. Changing sleep hours improved depressive mood and subjective sleep quality. Participants in study 2 had more stabilised sleep hours than those in study 1. This is the first mHealth study to demonstrate that sleep feedback proximally and distally improves sleep behaviours in a micro-randomised trial. The findings of this study encourage the use of digitalised health intervention trials that employs real-time health monitoring and personalised feedback.