One-third of our lives is spent sleeping, yet 30 to 40 percent of adults are reported to experience some form of insomnia. Japan in particular has the lowest sleep duration among the Organization for Economic Co-operation and Development (OECD) countries, falling at one hour below average.

Public health research has identified long commutes, noise, and light pollution from densely populated living environments as factors that impair sleep. While such metropolitan housing offers advantages in commuting time, its livability is far less than the suburbs. To find a balance between convenience and sleep, urban architecture research, which examines the relationship between housing location, size, and sleep health, could help answer the question of “Where and what size home should one have for better sleep?”

Seeking this answer, a research group led by Professor Daisuke Matsushita at Osaka Metropolitan University’s Graduate School of Human Life and Ecology investigated whether commuting time and residence predict insomnia and daytime sleepiness among residents of the Tokyo metropolitan area.

Based on an online survey using stratified random sampling, commute time was calculated using a route search system derived from the mode of transportation and postal codes of participants’ homes and workplaces. Insomnia and daytime sleepiness were assessed using the Athens Insomnia Scale and the Epworth Sleepiness Scale. The team also examined whether these relationships persist after adjusting for demographic and socioeconomic factors.

Data analysis revealed that even after adjusting for covariates, longer commutes predicted insomnia and daytime sleepiness, while smaller housing size predicted insomnia. Further, a trade-off was observed between commuting time and floor area in cases of insomnia. For housing units meeting the urban-oriented residential area standard of 95 m² for a four-person household, commuting times exceeding 52 minutes reached the insomnia cutoff value.

“Housing choices and supply that consider the trade-off between location and size may help improve the sleep health of commuters and reduce sleep-related economic losses in metropolitan areas,” said Professor Matsushita.

The findings were published in the Journal of Transport and Health.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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