Sleep duration, timing, and quality: how smartphone data predict labor productivity

Tsukuba, Japan—Most studies investigating the impact of sleep deprivation and circadian rhythm disruption on concentration and work performance have relied on self-reported questionnaires or small-scale surveys. To achieve an objective and large-scale assessment of habitual sleep behavior, this study analyzed data from around 80,000 Japanese workers using smartphone-based sleep applications. Parameters such as total sleep time, sleep latency, percentage of wake after sleep onset, chronotype, and discrepancies between weekday and weekend sleep timing (social jetlag) were examined. These metrics were linked to presenteeism scores (a validated measure of productivity loss) obtained using questionnaires.

Sleep duration demonstrated a U-shaped association with productivity, with short and long sleep duration linked to higher presenteeism. Additionally, individuals with longer sleep latency, frequent nocturnal awakenings, and greater social jetlag exhibited lower performance. Furthermore, unsupervised clustering using artificial intelligence techniques identified five distinct sleep phenotypes: "healthy sleepers," "long sleepers," "fragmented sleepers," "insomnia-prone," and "social jetlaggers." Productivity loss was the greatest in the "social jetlagger" and "insomnia-prone" groups, consistent across both sexes.

Therefore, apart from sleep duration, factors such as sleep timing, quality, and regularity are critical for maintaining work productivity. Moreover, smartphone-based sleep tracking can help identify at-risk individuals and guide personalized interventions to improve sleep health and occupational performance.

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This work was supported by the World Premier International Research Center Initiative (WPI) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) to Author MY; the Japan Agency for Medical Research and Development Moonshot Research and Development Program, (AMED; grant number: JP21zf0127005) to Authors MI and MY; the COI STREAM initiative launched in 2013 by MEXT and the COI-NEXT initiative launched in 2020 by MEXT (grant number: JPMJPF2017) to Author JS; and the JSPS Fund for the Promotion of Joint International Research (grantnumber: 22K21351) to Author MY.

_{Original Paper}

Title of original paper:
Association of Sleep Patterns Assessed by a Smartphone Application with Work Productivity Loss Among Japanese Employees

Journal:
npj Digital Medicine

DOI:
10.1038/s41746-025-02155-3

_{Correspondence}

Professor YANAGISAWA, Masashi
International Institute for Integrative Sleep Medicine (WPI-IIIS), Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba

_{Related Link}

Tsukuba Institute for Advanced Research (TIAR)

International Institute for Integrative Sleep Medicine (WPI-IIIS)

About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).

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About International Institute for Integrative Sleep Medicine (IIIS), University of Tsukuba
World-class institute for sleep medicine, aiming to solve the mechanism of sleep/wakefulness by conducting basic to translational research
The mission of IIIS is to be a multidisciplinary, international hub for the research to elucidate the function of sleep and the fundamental mechanisms of sleep/wake regulation, to elucidate molecular pathogenesis of sleep disorders and related diseases, to develop preventive measures, diagnostic methods, and treatments for sleep.