Summary: It has many names—the mental load, invisible work, or the “second shift”—but the impact is the same: a hidden burden that erodes sleep and sanity. A comprehensive study has finally quantified the cost of “Time Poverty.”
By analyzing nearly 4,000 workers, researchers found that while women often work fewer paid hours than men, their total labor (paid + unpaid) is significantly higher. This “extra shift” of household chores and caregiving is the primary predictor of nonrestorative sleep and poor mental health in women—a factor almost entirely ignored by traditional labor statistics.
Key Facts
- The Participation Gap: A stark disparity was found in daily domestic labor: 90% of women engaged in household chores compared to only 40% of men.
- Nonrestorative Sleep: For both genders, longer total working hours were directly linked to sleep that doesn’t feel refreshing, leading to chronic “silent exhaustion.”
- Mental Health Trigger: High total working hours (paid + unpaid) were a stronger predictor of psychological distress in women than paid employment alone.
- The “Time Poverty” Trap: Researchers define this as a state of being so overwhelmed by the combination of jobs and chores that there is literally no time left for “daily living” or recovery.
- Policy Blind Spot: Professors Akiko Morimoto and Naho Sugita argue that current labor policies fail because they only track “clocked-in” time, ignoring the essential labor that keeps society running.
Source: Osaka Metropolitan University
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,” stated Professor Morimoto.
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.
Key Questions Answered:
A: Actually, it doesn’t. The study found that even with shorter office hours, women’s total working day is often longer and more fragmented. This prevents the brain from entering a “rest and digest” state, leading to nonrestorative sleep—the kind where you wake up feeling just as tired as when you went to bed.
A: It’s often the “invisible” nature of the work. Managing schedules, doctor’s appointments, and meal prep requires constant cognitive multitasking. This “mental load” creates a baseline of stress that doesn’t end when the laptop closes, leading to higher rates of mental distress.
A: The researchers suggest we need to start quantifying this work in official data. If a doctor or policymaker only asks, “How many hours do you work at your job?” they are missing half the patient’s life. Recognizing unpaid labor as “work” is the first step toward institutional designs (like shorter work weeks or better childcare) that actually support health.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this mental health research news
Author: Lee Scott
Source: Osaka Metropolitan University
Contact: Lee Scott – Osaka Metropolitan University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Associations of total daily working hours encompassing unpaid care and domestic work with nonrestorative sleep and mental health in middle-aged Japanese men and women: a cross-sectional study” by Akiko Morimoto, Hideaki Furuki, Naho Sugita, Risako Hayashi, and Nao Sonoda. Social Science & Medicine
DOI:10.1016/j.socscimed.2026.118965
Abstract
Associations of total daily working hours encompassing unpaid care and domestic work with nonrestorative sleep and mental health in middle-aged Japanese men and women: a cross-sectional study
Objective
This study aimed to explore the associations of total daily working hours encompassing unpaid care and domestic work with nonrestorative sleep and mental health in healthy middle-aged Japanese men and women.
Methods
This cross-sectional study analyzed data derived from a postal survey of 3959 healthy middle-aged Japanese adults engaged in paid employment. Participants self-reported the average daily hours spent on income-generating work, housework, childcare, and caregiving.
Nonrestorative sleep was assessed using a widely used single-item measure, and mental health was evaluated using a five-point Likert scale, dichotomized into “very good/good/average” and “poor/very poor.”
Results
Despite spending less time on paid employment, women reported significantly longer total daily working hours than men, primarily because of their greater involvement in unpaid housework. ROC curve analysis revealed that total daily working hours had a higher predictive value for nonrestorative sleep and poor mental health than income-generating work hours alone, particularly in women.
After adjusting for confounders, longer total working hours were significantly associated with higher adjusted odds ratios for nonrestorative sleep in both genders and with poor mental health in women.
Conclusions
Total daily working hours encompassing unpaid care and domestic work represent an important factor influencing sleep and mental health outcomes, with notable associations observed in women.
These findings underscore the importance of incorporating unpaid care and domestic work into time burden assessments and support the development of gender-equitable strategies that account for total working hours in health and social policies.
