Telemonitored sleep quality and daily activity are associated with mental health outcomes among Japanese workers

Reports on the relationship between the sleep/activity cycle and mental health exist. However, self-reported sleep/activity evaluations are ambiguous; thus, objective evaluations are needed. We objectively examined the relationships between sleep parameters, daily activity levels, and mental health outcomes among 81 Japanese adults. Each participant wore a Fitbit Sense 2 for five days to monitor daily activity and underwent one night of sleep electroencephalography. Distress, anxiety, depression, harm avoidance, and sleep symptoms were assessed using questionnaires. Sleep metrics included total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), and sleep stages. Subjective ratings of daily sleep-restorativeness were also collected. Longer SOL correlated with higher distress and life interference scores, whereas SE was negatively associated with distress interference. Decreased N2 sleep was linked to elevated anxiety and depression, while increased N3 sleep correlated with lower harm avoidance. A higher TST was associated with reduced insomnia severity. Vigorous activity was associated with lower harm-avoidance scores. Ratings of restorativeness were positively related to vigorous activity and mental health outcomes. These findings suggest associations between objective sleep metrics, physical activity, and mental health, which may inform future approaches to mental health assessment.