Association between ensuring a daily rest period in the workplace and workers’ sleep: Evidence from a matched employer–employee survey in Japan

There was no significant association between ensuring a daily rest period (DRP) in the workplace and short sleep duration among full-time workers overall.

• Cross-sectional data from a matched employer–employee survey was used
• Sample consisted of 4202 full-time workers from 2121 workplaces in Japan
• Logistic regression models were employed to predict sleep quantity and quality outcomes
• The null finding applied to the overall full-time worker sample regardless of DRP length

Increasing working hours was significantly associated with higher odds of short sleep duration.

• This association was found across the full sample of 4202 full-time workers
• The association between working hours and short sleep duration appeared weaker among workers in workplaces with ≥11 h DRP
• Logistic regression models were used to identify this association
• This moderation effect was observed at the workplace level

Ensuring a DRP of ≥11 hours was significantly associated with lower odds of short sleep duration among overtime workers.

• This finding was specific to workers classified as overtime workers, not all full-time workers
• The threshold of ≥11 hours was the DRP duration associated with the significant finding
• This suggests the DRP may be particularly relevant for workers with extended working hours
• The analysis used logistic regression models with DRP as a workplace-level variable

Ensuring a DRP of ≥11 hours was significantly associated with lower odds of daytime sleepiness among full-time workers.

• Daytime sleepiness was one of multiple sleep quality outcomes examined
• Other sleep quality outcomes examined included insufficient sleep, early morning awakening, and nonrestorative sleep
• This association held for the full sample of full-time workers (n=4202)
• The ≥11 h DRP threshold was significant for this outcome at the full-sample level, unlike short sleep duration

The moderating effect of workplace DRP on the association between working hours and short sleep duration appeared more evident among women than among men.

• These analyses were described as exploratory and stratified by gender
• The pattern of DRP moderating the working hours–sleep association appeared weaker or less evident in men
• Gender-specific differences were also observed for insufficient sleep, early morning awakening, daytime sleepiness, and nonrestorative sleep
• The authors caution these are exploratory findings and not primary analyses

Gender-specific differences in multiple sleep outcomes were observed when examining the association with DRP.

• Outcomes showing gender-specific differences included insufficient sleep, early morning awakening, daytime sleepiness, and nonrestorative sleep
• These differences were identified through exploratory gender-stratified analyses
• The study design was cross-sectional, limiting causal interpretation of these differences
• The matched employer–employee survey design allowed for workplace-level DRP data to be linked to individual worker outcomes

The study used a matched employer–employee survey design linking workplace-level daily rest period policies to individual worker sleep outcomes.

• The sample included 4202 full-time workers nested within 2121 workplaces in Japan
• The matched design allowed workplace-level DRP ensuring practices to be analyzed as a contextual variable
• Data were cross-sectional, precluding causal inference
• DRP was categorized with a key threshold of ≥11 hours based on common work-interval system standards