NEW YORK, May 14: Long working hours may cause structural changes in the brain, particularly in areas associated with emotional regulation and executive function, including working memory and problem-solving, according to preliminary research published in Occupational & Environmental Medicine. The findings suggest that overwork could lead to neuroadaptive changes that may impact both cognitive and emotional health.

The study highlights the well-established link between long working hours and heightened risks of cardiovascular disease, metabolic disorders, and mental health issues. The International Labor Organization (ILO) estimates that overwork results in more than 800,000 deaths annually. While the behavioral and psychological consequences of overwork are fairly well understood, the underlying neurological mechanisms and anatomical changes have not been fully explored, the researchers note.

To investigate further, the researchers used structural brain volume analysis to examine the impact of long working hours on specific brain regions in healthcare workers who routinely work more than 52 hours a week. Data from the Gachon Regional Occupational Cohort Study (GROCS) and MRI scans from a project on the effects of working conditions on brain structure were used for this analysis.

Participants in GROCS were asked to undergo an additional MRI scan, and after excluding those with missing data or poor-quality scans, the final analysis included 110 participants. Among these, 32 worked excessive weekly hours (28%) while 78 worked standard hours.

Notably, those working longer hours were significantly younger, had less work experience, and were more highly educated than those working standard hours.

The researchers used voxel-based morphometry (VBM), a neuroimaging technique that identifies regional differences in gray matter, and atlas-based analysis, which compares brain scan structures to pre-defined references. The comparative analysis revealed significant changes in the brain regions of those working 52 or more hours a week, particularly those related to executive function and emotional regulation.

For instance, the atlas-based analysis showed a 19% increase in the volume of the middle frontal gyrus in individuals working long hours compared to those working standard hours. This area of the brain is crucial for cognitive functions such as attention, working memory, and language processing.

VBM revealed peak increases in 17 regions, including the middle frontal gyrus, the superior frontal gyrus (involved in attention, planning, and decision-making), and the insula (key in emotional processing, self-awareness, and understanding social context).

While this study is small and observational, and no definitive conclusions can be drawn about cause and effect, the researchers emphasize that it represents an important first step in understanding the link between overwork and brain health. The study also suggests that the observed changes in brain volume may reflect neuroadaptive responses to chronic occupational stress, although the exact mechanisms remain unclear.

The researchers note, "These changes in brain volume could provide a biological basis for the cognitive and emotional challenges often experienced by overworked individuals. Future longitudinal studies with multiple imaging methods are needed to confirm these findings and further explore the underlying mechanisms."

The study's conclusions underscore the need for addressing overwork as a significant occupational health issue and call for workplace policies to reduce excessive working hours.