Scientists Warn: Long Work Hours May Physically Alter Your Brain

Overwork can lead to neuroadaptive changes that impair cognitive and emotional health.

Working long hours may actually change the structure of your brain, according to new research published in Occupational & Environmental Medicine. The study points to alterations in key brain areas responsible for emotional regulation and executive functions like working memory and problem solving.

Researchers believe that chronic overwork could trigger neuroadaptive changes, which might have lasting effects on both cognitive performance and emotional well-being.

The dangers of working too much extend beyond burnout. Long hours have already been linked to higher risks of heart disease, metabolic disorders, and mental health problems. The International Labour Organisation (ILO) reports that overwork contributes to more than 800,000 deaths worldwide each year.

While the mental and emotional toll of overwork is well recognized, scientists are still uncovering what happens inside the brain itself.

Study Design and Methods

To explore this further, the researchers deployed structural brain volume analysis to compare the impact of overwork on specific brain regions in healthcare workers routinely clocking up long working hours, defined as 52 or more a week.

They drew on data from the Gachon Regional Occupational Cohort Study (GROCS) and from MRI scans carried out for a research project on the effects of working conditions on brain structure.

Participants in GROCS were asked to have an additional MRI scan, and the final analysis included 110 people after excluding those with missing data or poor MRI image quality. Most were clinicians: 32 worked excessive weekly hours (28%); 78 worked standard hours.

Those putting in long working hours every week were significantly younger, had spent less time in work and were more highly educated than those clocking up standard hours.

Differences in brain volume were assessed using voxel-based morphometry (VBM), a neuroimaging technique that identifies and compares regional differences in levels of grey matter, and atlas-based analysis, which uses pre-defined references to identify and label structures in images like brain scans.

Key Findings on Brain Volume Changes

Comparative analysis of the findings showed that people who worked 52 or more hours a week displayed significant changes in brain regions associated with executive function and emotional regulation, unlike participants who worked standard hours every week.

For example, atlas-based analysis revealed a 19% increase in the volume of the middle frontal gyrus among those clocking up long working hours compared with those working standard hours.

This part of the brain has a major role in various cognitive functions, particularly in the frontal lobe. It’s involved in attention, working memory, and language-related processing.

VBM showed peak increases in 17 regions, including the middle frontal gyrus, the superior frontal gyrus, which is involved in attention, planning, and decision-making, and the insula.

The insula has a key role in integrating sensory, motor, and autonomic feedback from the body. It’s involved in emotional processing, self-awareness, and understanding social context.

This is a small observational snapshot study, and as such, no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that in the absence of long-term data, it’s unclear whether these structural changes are a consequence of overwork or a predisposing factor.

But they nevertheless point out: “While the results should be interpreted cautiously due to the exploratory nature of this pilot study, they represent a meaningful first step in understanding the relationship between overwork and brain health.”

They add: “Notably, the increased brain volumes observed in overworked individuals may reflect neuroadaptive responses to chronic occupational stress, although the exact mechanisms remain speculative.”

They continue: “The observed changes in brain volume may provide a biological basis for the cognitive and emotional challenges often reported in overworked individuals. Future longitudinal and multi-modal neuroimaging studies are warranted to confirm these findings and elucidate the underlying mechanisms.”

And they conclude: “The results underscore the importance of addressing overwork as an occupational health concern and highlight the need for workplace policies that mitigate excessive working hours.”

Reference: “Overwork and changes in brain structure: a pilot study” by Wonpil Jang, Sungmin Kim, YouJin Kim, Seunghyun Lee, Joon Yul Choi and Wanhyung Lee, 1 March 2025, Occupational and Environmental Medicine.
DOI: 10.1136/oemed-2025-110057

Funding: Ministry of Education of the Republic of Korea; National Research Foundation of Korea

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