Summary: Preliminary research indicates that consistently working more than 52 hours per week may be associated with measurable changes in brain regions involved in emotional regulation, memory, and decision-making. MRI scans of healthcare workers showed increased grey matter volume in areas such as the middle and superior frontal gyri and the insula.
These anatomical differences may reflect the brain’s neuroadaptive reaction to prolonged occupational stress. The long-term consequences for cognitive function and emotional well-being remain uncertain, but the results highlight the importance of treating excessive working hours as a significant occupational health concern.
Key Facts:
- Structural brain changes: Extended working hours were associated with greater volume in brain regions linked to executive function and emotional regulation.
- Neuroadaptive stress response: The observed differences may represent the brain adapting to chronic work-related stress rather than direct damage.
- Health implications: In addition to known cardiovascular and mental health risks of overwork, emerging evidence now points to potential structural brain effects that deserve further study.
Source: BMJ Group
Working long hours may change brain structure in regions tied to emotional control and executive functions such as working memory and problem solving, according to preliminary findings published online in Occupational & Environmental Medicine.
The researchers suggest that sustained overwork could induce neuroadaptive changes with possible implications for cognition and emotional health. However, these observations are exploratory and should be interpreted cautiously.
Long working hours are already linked to higher risks of heart disease, metabolic problems, and mental health conditions. The International Labour Organisation (ILO) estimates that overwork contributes to hundreds of thousands of deaths annually, underscoring the broader public health impact of excessive working time.
While behavioral and psychological effects of overwork have been relatively well described, the neurological mechanisms and anatomical changes associated with prolonged working hours are less well understood. This study set out to explore whether structural differences in the brain are detectable among people who routinely work long weeks.
To investigate this, the team analyzed structural MRI scans and applied voxel-based morphometry (VBM) and atlas-based analysis to measure regional grey matter volume. The sample was drawn from the Gachon Regional Occupational Cohort Study (GROCS) and a related MRI research project focused on working conditions and brain structure.
After excluding participants with incomplete data or poor-quality scans, the final sample comprised 110 individuals, most of whom were clinical healthcare workers. Of these, 32 people (about 28%) reported working 52 hours or more per week, while 78 reported standard weekly hours.
People in the long-hours group tended to be younger, had fewer years in the workforce, and were more highly educated compared with those working standard hours. The researchers accounted for these differences in their analyses, but they note potential confounding factors that could influence results.
Atlas-based analysis identified a roughly 19% larger volume in the middle frontal gyrus among those working long hours compared with standard-hour workers. The middle frontal gyrus is a frontal lobe region involved in attention, working memory, and language-related processing—functions integral to executive control.
Voxel-based morphometry revealed peak increases across 17 regions, including the middle and superior frontal gyri and the insula. The superior frontal gyrus contributes to attention, planning, and decision-making. The insula plays a central role in integrating sensory, motor, and autonomic signals, and is implicated in emotional processing, self-awareness, and social cognition.
The authors emphasize that this is a small, observational pilot study, so no causal claims can be made. Without longitudinal data it remains unclear whether increased grey matter volume is a consequence of prolonged working hours, a preexisting characteristic that predisposes someone to different work patterns, or a combination of both.
Nevertheless, the researchers argue that the findings offer a useful starting point. They propose that larger brain volumes in specific regions may represent neuroadaptive responses to chronic occupational stress—changes that could help explain the cognitive and emotional complaints commonly reported by people who are overworked.
Future research should adopt longitudinal designs and combine multiple imaging modalities to confirm these observations, explore underlying biological mechanisms, and track whether structural differences persist, progress, or reverse when working conditions change.
From a public health and occupational policy perspective, the results add weight to calls for workplace measures that limit excessive hours and address chronic stress. Employers, clinicians, and policymakers should consider the potential neurological as well as physical and mental consequences of prolonged overwork when designing interventions and protections.
About this neuroscience research news
Author: Caroline White
Source: BMJ Group
Contact: Caroline White – BMJ Group
Image credit: Neuroscience News
Original Research: Findings to appear in Occupational and Environmental Medicine