A South Korean study finds that working over 52 hours a week may physically change the brain – a reflection of the toll of long working hours.
“Just work harder.”
It is the mantra that built modern Asia – from Singapore’s grind culture to South Korea’s 12-hour workdays. But a growing research suggests there may be a biological cost to all that late nights, endless deadlines, and emails at midnight: your brain.
A new study published in Occupational & Environmental Medicine has found that consistently working long hours could physically change your brain – particularly in regions linked to emotional regulation, memory and even problem solving.

Researchers examined MRI scans of 110 participants and analysed their brain volume to compare the impact of overwork on different brain regions. They discovered an interesting trend: those who worked 52 or more hours a week displayed significant changes in their brain versus their counterparts with a healthier work-life balance.
Key Findings
The study monitored different regions of the brain, which played different roles in our cognitive functions.
Participants who worked longer than 52 hours per week had a 19% increase in the volume of their middle frontal gyrus. It plays a role in working memory, attention, and language-related processing. There were also increases in other regions such as the superior frontal gyrus (thought to contribute to higher cognitive functions and to working memory); and the insula (involved in interoception, emotional processing, and decision-making).
The researchers commented: “Notably, the increased brain volumes observed in overworked individuals may reflect neuroadaptive responses to chronic occupational stress, although the exact mechanisms remain speculative.”
Adaptation or a Warning Sign?
Why does work have such an impact on the brain?
Experts point to a mix of chronic stress, poor sleep, and mental fatigue – all of which are common in high-demand, long-hour jobs.
Chronic stress can raise cortisol levels in the body, which over time damages blood vessels and interferes with the brain’s ability to repair itself. Poor sleep, meanwhile, reduces the brain’s capacity to clear toxins, accelerating the buildup of harmful proteins associated with Alzheimer’s disease.
“The observed changes in brain volume may provide a biological basis for the cognitive and emotional challenges often reported in overworked individuals.” The researchers added.
Rather than signs of enhancement, the increased brain volume in these areas could potentially be a stress response. The brain is working harder to keep up, but at some point it may start to slip. Over time, this can lead to blunders in key functions like decision-making, focus, and emotional control.
Just because your brain is adapting does not mean it is thriving.
Overwork Culture in Asia
The study’s findings hit especially close to home. In Asia, long working hours are often worn as a badge of honour. Japan even has a word – karōshi (過労死) – to describe death by overwork. In Singapore, a 2021 survey have found that over 25% of workers clock over 48 hours a week.
In cultures where professional identity is tightly linked to self-worth and stability, conversations about workload often take a back seat to performance. But with more and more evidence of the dangers of overworking, the case for better work-life boundaries is becoming harder to ignore.
Being overworked harms not only the brain. Research from the World Health Organisation and the International Labour Organisation revealed that longer working hours have increased mortality rates in the APAC region by 29%.
How to Protect Your Brain
As individuals, protecting brain health in high-pressure work environments starts with creating boundaries, and keeping them. That could mean resisting the habit of checking emails late into the night, or carving out time for rest.

Sleep plays a critical role in the brain’s ability to process, repair and reset. Consistently short-changing sleep in favour of more work hours has long-term consequences. Consider stepping away from your desk for short walks or incorporating regular physical activity to help your brain buffer against the wear and tear of chronic stress.
Organisations have an even greater responsibility to examine how workplace culture, policies and expectations may be fuelling this problem. Beyond encouraging staff to take leave, it helps to build a culture where rest is respected, not penalised. Rethinking what productivity means, offering flexibility where possible, and recognising mental health as a legitimate factor in performance can go a long way in supporting a healthier, more sustainable workplace.
When overwork becomes the norm, the brain adapts – and not without a cost. And in the long run, no system that depends on overstretched workers is truly sustainable.
External References
- Jang W, Kim S, Kim Y, et al. Overwork and changes in brain structure: a pilot study. Occupational and Environmental Medicine. 2025;82:105-111. DOI: 10.1136/oemed-2025-110057
- Instant Offices. (2022). Most overworked APAC countries 2022. Retrieved from https://www.instantoffices.com/blog/featured/most-overworked-apac-countries/
- Holth JK, Fritschi SK, Wang C, Pedersen NP, Cirrito JR, Mahan TE, Finn MB, Manis M, Geerling JC, Fuller PM, Lucey BP, Holtzman DM. The sleep-wake cycle regulates brain interstitial fluid tau in mice and CSF tau in humans. Science. Jan. 24, 2019. DOI: 10.1126/science.aav2546