Working long hours may lead to more than just burnout—new research suggests it could physically alter the brain. A study published this week in Occupational and Environmental Medicine has found significant brain structure differences in individuals who regularly work excessive hours, potentially explaining links to anxiety, depression, and reduced cognitive function.
The study, led by Wanhyung Lee from the Department of Preventive Medicine at Chung-Ang University in Seoul, analyzed the brains of 110 healthcare workers. Some participants regularly worked more than 52 hours per week—the threshold for overwork under South Korean labor law—while others worked within legal limits.
Using MRI scans, the researchers identified differences in 17 brain regions between overworked individuals and those with typical workloads. These affected areas are primarily associated with executive function tasks, such as reasoning, decision-making, attention, and emotional regulation.
“We anticipated that prolonged stress from overwork would affect brain structure, but finding increased volume in certain brain areas was somewhat unexpected,” Lee told TIME. He suggested this might represent a “neuroadaptive response,” in which the brain attempts to compensate for increased demands caused by long working hours.
The researchers noted that advanced imaging technology allowed them to detect even minor structural variations in brain tissue, opening a new window into how occupational stress affects human biology.
Of particular concern were changes in areas that regulate emotion and interpersonal behavior. Lee noted that such alterations might contribute to emotional instability, heightened anxiety, and difficulty managing social relationships.
The findings come amid growing global attention to the impact of overwork on mental and physical health. South Korea, known for its demanding work culture, has recently taken steps to reduce excessive work hours. This study adds further scientific weight to those efforts by revealing potential long-term neurological effects.
It remains unclear whether these brain changes are permanent. “Longitudinal studies will be essential to understand if these brain structural changes are reversible or persist long-term,” Lee said. He plans to expand his research to include larger populations and follow participants over extended periods to determine if adjusting work schedules can reverse these effects.
The study serves as a reminder of the hidden costs of overwork and the importance of work-life balance—not just for mental health, but potentially for brain health as well.