Longer working hours associated with higher risk of nonrestorative sleep and poor mental health

Mental load, invisible work, "the extra shift"; no matter the newly coined term, unpaid work in the domestic sphere, predominantly done by women, is a hidden burden eating away at the sleep and mental health of those tasked with it. This work is essential to keep everyone's daily lives on track, from meal prep and clean clothes to school drop-offs and doctor's appointments, yet its importance is often ignored, undermined, and even belittled by the very society dependent on it.

Add paid employment, and the recipe for disaster is complete, leaving those juggling both to drown in silent exhaustion and mental distress. This occurrence is often described as time poverty, a state in which they are overwhelmed by paid and unpaid work and unable to secure sufficient time for daily living. However, much of the research on this topic has solely focused on paid working hours, thus the impact of total working hours, paid working hours + unpaid working hours, has not been sufficiently examined.

For this reason, a research group led by Professor Akiko Morimoto from the Graduate School of Nursing and Professor Naho Sugita from the Graduate School of Economics at Osaka Metropolitan University comprehensively examined the relationship between total daily working hours, nonrestorative sleep, and mental health. A self-administered postal questionnaire with questions focused on demographic variables, total amount paid and unpaid working hours, sleep quality, and mental health was distributed across five cities in Osaka Prefecture. Out of 12,446 participants, answers from 3,959 healthy Japanese workers, 1,900 men and 2,059 women, aged 40 to 64, were analyzed.

The results revealed that, although women work fewer paid hours than men, they spend more time on unpaid work, resulting in longer working hours. A significant disparity was particularly observed in the rate of participation in household chores, with approximately 90% of women and approximately 40% of men engaging in such activities.

Furthermore, it was confirmed that longer working hours were associated with a higher risk of nonrestorative sleep for both men and women. They also correlated with a higher risk of poor mental health in women.

For women, total daily working hours are a more important predictor of nonrestorative sleep and poor mental health than paid working hours alone."

Professor Akiko Morimoto, Graduate School of Nursing, Osaka Metropolitan University

Professor Sugita concluded, "Going forward, we expect that quantifying total daily working hours and incorporating this data into policy-making and institutional design will help reduce health disparities and achieve gender equality."

The study was published in Social Science & Medicine.