LONDON: Working for long hours may lead to structural changes in the brain, potentially affecting emotional regulation and cognitive performance, according to a new study published in the journal Occupational & Environmental Medicine.
The research, based on brain scans of healthcare workers, found notable differences in brain regions responsible for executive functions and emotional control among those clocking 52 or more hours per week, compared with those working standard hours.
Scientists from South Korea, who led the study, suggest that chronic overwork could lead to “neuroadaptive changes”—a phenomenon where the brain structurally adapts to prolonged stress—which may have lasting consequences on mental functioning and overall well-being.
“While the mental and emotional toll of working long hours has long been recognised, this is among the first studies to reveal measurable changes in brain structure associated with overwork,” the authors noted.
The team analysed data from the Gachon Regional Occupational Cohort Study (GROCS), which investigates how working conditions affect health.
For this study, participants underwent MRI scans to assess grey matter volume in various parts of the brain.
After excluding incomplete or poor-quality scans, the final sample included 110 participants—32 of whom were regularly working more than 52 hours per week.
Most participants were clinicians. Interestingly, those working longer hours tended to be younger, more highly educated, and had fewer years of work experience than their counterparts working standard hours.
To assess the structural differences, the researchers used two neuroimaging techniques: voxel-based morphometry (VBM), which detects changes in grey matter density, and atlas-based analysis, which uses pre-defined brain maps to pinpoint anatomical differences.
The findings showed that individuals working longer hours had significantly higher grey matter volume in 17 brain regions.
Notably, there was a 19% increase in volume in the middle frontal gyrus—a region of the frontal lobe linked to working memory, attention, and language processing.
In addition to the middle frontal gyrus, the superior frontal gyrus—critical for decision-making and planning—and the insula were also affected.
The insula plays a crucial role in emotional processing, self-awareness, and social behaviour.
“Such structural brain alterations suggest the possibility of long-term impacts on mental health and cognitive capacity,” the researchers warned, although they cautioned that further studies are needed to understand the long-term implications.
The study adds to growing global concern over the health risks posed by long working hours. The International Labour Organization (ILO) has previously reported that overwork contributes to more than 800,000 deaths worldwide annually, primarily from stroke and heart disease.
The authors of the study have called for further research to determine whether these brain changes are reversible and to explore their functional impact on cognition and mental health over time.
