Working 52+ hours a week may physically change your brain, warns new study

Business Standard

22-05-2025

If you've ever bragged about 'killing it' at work by clocking long hours week after week, this might be your wake-up call. A new study titled 'Overwork and changes in brain structure: a pilot study', published in the journal Occupational & Environmental Medicine (a BMJ publication), has found that working 52 hours or more per week may actually be altering your brain, particularly the regions responsible for memory, problem-solving, and emotional regulation.
Conducted by a team of South Korean researchers from Yonsei University, Chung-Ang University, and Pusan National University, the study used advanced brain imaging techniques to examine 110 healthcare workers. They found that overworked individuals showed notable structural changes in their brains, changes that could help explain the emotional and cognitive struggles often reported by people who work excessively long hours.
How does working long hours affect brain structure?
The researchers compared healthcare workers who routinely worked 52 hours or more a week to those who worked fewer hours. Using Magnetic Resonance Imaging (MRI)-based techniques, voxel-based morphometry (VBM) and atlas-based volume analysis, they found that overworked individuals had significantly increased brain volume in areas associated with executive function (like decision-making and working memory) and emotional regulation.
One of the most affected regions was the left middle frontal gyrus, along with the insula and superior frontal gyrus, parts of the brain linked to emotional balance and problem-solving. While these changes might sound like brain 'growth,' they are more likely neuroadaptive responses to chronic stress and fatigue.
What did the study reveal about the brain and overwork?
Here are the key findings:
The left caudal middle frontal gyrus showed a 19 per cent increase in volume in the overworked group. Significant volume increases were also seen in 17 other brain regions, including those tied to executive and emotional functions.
These changes correlated positively with the number of hours worked each week.
Even after adjusting for confounding lifestyle factors like smoking and exercise, many associations held strong.
Notably, while increased grey matter is often interpreted as a sign of learning or positive adaptation, researchers caution that in the context of overwork, it may reflect compensatory or even maladaptive responses to chronic stress and lack of rest.
While we already know overwork is tied to mental health issues like depression and anxiety, this research goes deeper to understand the physical and structural changes in the brain that may underlie these problems.
Previous studies mostly focused on psychological and behavioural outcomes. This study adds a new layer of evidence by connecting those outcomes with biological changes in brain anatomy.
Which brain functions are impacted by structural changes?
The affected brain regions help regulate how we make decisions, solve problems, and manage emotions. Alterations in these areas could contribute to:
Reduced cognitive efficiency
Difficulty in focusing or problem-solving
Emotional instability
Higher susceptibility to burnout, anxiety, and depression
And the consequences might not just be short-term. Over time, these changes could impact long-term brain health, including risks for cognitive decline.
What workplace changes does the study recommend?
The study's authors call for immediate action from employers and policymakers, especially in high-demand professions like healthcare. They emphasise, 'Our findings underscore the importance of addressing overwork as an occupational health concern and highlight the need for workplace policies that mitigate excessive working hours.'
Given that the International Labour Organization (ILO) already estimates 800,000 deaths annually from overwork, the study lends urgent neurobiological weight to a public health issue that's been brewing for decades.
What can employees and employers do to protect brain health?
While this is a pilot study and further research is needed, it does tell us that brain health should be a priority in the conversation about work-life balance.
Here are some actionable takeaways:
Employers should design better shift schedules, encourage breaks, and cap weekly hours to reduce mental load.
Workers should monitor their mental and emotional states, prioritise rest and recovery, and seek help when signs of burnout appear.
Policymakers should set stricter guidelines around maximum work hours and implement regulations to protect employee well-being.
Long hours may seem necessary sometimes, but your brain might be paying the price in ways you cannot see. The next time you're tempted to push through yet another late night at work, just remember: boundaries and balance are important for your brain health. For more health updates, follow #HealthWithBS