A new study published in the Journal of Occupational and Environmental Medicine reveals that long working hours may cause significant changes to brain structure. Conducted in South Korea, the research followed 110 healthcare workers split into overworked and non-overworked groups. Using MRI scans and neuroimaging techniques, researchers found that individuals working 52 hours or more per week had increased gray matter in brain regions linked to executive function and emotional regulation, such as the middle frontal gyrus and insula. These changes may explain the cognitive and emotional difficulties often reported by overworked individuals.

The study suggests a possible biological basis for the mental and emotional toll of overwork, reinforcing earlier findings from the WHO and ILO that long working hours are associated with severe health risks, including a higher risk of diabetes, cognitive decline, and even premature death. Although the brain changes may be partially reversible with reduced stress, full recovery may take significant time. Researchers urge caution in interpreting results due to the small sample size and limited demographic, but call this a meaningful step toward understanding how overwork affects brain health.Among all occupational risk factors identified to date, long working hours contribute the largest burden of disease.

Experts not involved in the study, including WHO&rsquos Frank Pega and Jonny Gifford of the Institute for Employment Studies, emphasize that this research strengthens the case for policy interventions. The neurological evidence highlights the need for governments, employers, and workers to prioritize healthy work limits. As overwork becomes a global health issue, these findings offer compelling reasons to rethink how long hours are normalized in the modern workplace.