Now, new research published in the journal Occupational & Environmental Medicine suggests that working long hours can even change the brain’s physical structure. 

To conduct the study, researchers from Korea reviewed the working hours and MRIs of over 100 health care workers between 2021 and 2023. Those who worked 52 hours or more per week were classified as overworkers. 

The researchers discovered changes in the brain structure of overworkers, particularly in regions that account for emotional processing and executive functioning. The results suggest that “the increased brain volumes observed in overworked individuals may reflect neuroadaptive responses to chronic occupational stress, although the exact mechanisms remain speculative,” wrote the researchers. 

One explanation for the brain changes is that overworking can disrupt sleep, which can, in turn, heighten the stress response and increase the risk for mental health conditions like anxiety and depression. 

“Overwork is a combination of physical and emotional overexertion and a lack of rest. Overuse and lack of rest can negatively affect the brain,” the researchers conclude. 

However, the researchers note that their conclusions are “preliminary” and call for further research, such as whether these structural changes can affect the brain into old age and cause changes in decision making and emotional regulation.

“Future research should explore the long-term implications of these structural brain changes and whether they lead to cognitive decline or mental health disorders,” the paper concludes. 

For now, people can take steps to help protect their brain health even if work feels like a slog, like sleeping at least seven hours a night, limiting screen time, and taking micro breaks during the workday.