“Overworking isn’t just ineffective, it’s altering our brains.”
Growing up in the 90s, there was this famous commercial that aired on repeat, it was part of a campaign by the Partnership for a Drug-Free America. If you’re an ‘80s or ‘90s baby, you probably have the tagline stuck in your head.
This is drugs… this is your brain on drugs… any questions? The scene opens with a pan of hot oil. A voice says, “This is drugs.” Then an egg is cracked into the oil, sizzles violently, and the voice declares: “This is your brain on drugs.”
The metaphor was clear and haunting: doing drugs would fry your brain and leave it forever altered. It became one of the most memorable ads in television history.
Now, decades later, we might need a new version: this is your brain on overwork.
For years, we’ve discussed overwork in terms of its effects on our bodies: stress, fatigue, brain fog, and burnout. However, science is now taking us even deeper. A new pilot study out of South Korea is the first to provide neuroimaging evidence showing that chronic overwork is not just a psychological phenomenon, but it has structural consequences in the brain.
Conducted by researchers at Yonsei University and Chung-Ang University, the study compared MRI scans of 110 healthcare workers. Some worked more than 52 hours a week (considered the legal upper limit in Korea); others worked more typical hours. The findings? Overwork can be linked to significant changes in the volume of brain regions responsible for executive functioning and emotional regulation.
In other words, our jobs may literally be rewiring our brains and not for the better.
How Overworking Affects the Brain
The researchers discovered that the brains of overworked individuals looked noticeably different. Certain parts of the brain, especially those that help us plan, make decisions, stay focused, and manage our emotions, were physically larger in people who worked long hours.
This might sound like a good thing at first, but it isn’t necessarily. These changes don’t suggest that the brain is getting stronger. Instead, it suggests that the brain is working harder than it should, as it attempts to compensate for stress, sleep deprivation, and the cognitive and emotional strain of overexertion. It’s like a muscle that’s being overused; it grows, but that growth can signal strain, not strength.
Similar to other muscles in the body, after regular strain, the brain needs to rest. However, people who overwork regularly, rarely get that rest.
Why Bigger Isn’t Always Better
Increases in grey matter volume in the brain are often seen in learning or skill-building contexts. But they’re also observed in people with anxiety and mild depression. In this study, the volume increases may be a result of the brain compensating for ongoing stress, emotional suppression, and inadequate recovery time. The larger areas of the brain are the brain’s way of saying, “I’m under pressure.”
And here’s the twist: other studies have linked these same brain regions to impaired performance when overstimulated. So, more volume doesn’t mean better functioning, just harder, more effortful processing because the brain is working overtime as well.
It’s not resilience. It’s survival.
This dovetails with the well-known economic principle: the law of diminishing returns. It tells us that after a certain point, putting in more effort leads to less output, not more. When applied to work hours, research has shown that productivity sharply declines after 50 hours per week, and after 55, it essentially falls off a cliff. And now we have the brain research to back up why this is- our brains are literally and physically strained, no wonder we become less effective, more irritable, and more prone to mistakes.
Additional hours don’t lead to more effectiveness; they lead to mental depletion.
The Burnout Loop, in Brain Form
You have felt it, I have felt it, the world has felt it, and now the science is catching up with more evidence to prove that working more doesn’t mean achieving more.
What this study reveals is eerily aligned with what many of us have known but struggle to accept: the reality that the longer we push through exhaustion and overwork, the more disconnected we become from our cognition, our bodies, and emotions.
This is the burnout loop at the neurological level. Chronic overwork leads to emotional dysregulation, mental fatigue, and impaired executive function, which makes us less able to prioritize, less able to rest, and more likely to keep pushing through. That is because, to a large degree, we have to ignore the headaches, the exhaustion, the depletion, the loneliness, to keep overworking.
A closed circuit of exhaustion.
This isn’t just about individual well-being. It’s about our collective capacity to lead, create, and care.
What this Means for Workplaces and Workers
Now that we have a pilot study that says overwork may be a biomarker of brain strain. Leaders and organizations need to stop ignoring the science. For employers, this study highlights a crucial truth that organizations and leaders still struggle to accept: long hours are not only ineffective but also harmful to workers, teams and work cultures.
Leadership needs to shift the success metric from face time to functional time, and from endurance to impact.
For individuals, it serves as yet another wake-up call. If the risks of burnout, anxiety, depression, loneliness, and cardiovascular disease weren’t enough to spark a moment of pause, now you have MRI data to tell you that overworking isn't working.
Rest is not a luxury. It’s the only way to sustainable effectiveness.
Re-Imagining Success: From the Inside Out
We live in a culture that still treats burnout as a personal failure and overwork as a virtue. However, this study reinforces what we have long known: our biology is pushing back. The brain is adapting to survive an unsustainable way of working. And that adaptation comes at the cost not only of our health but also of clarity, creativity, and connection.
Success reimagined isn’t about pushing through until we break. It’s about creating a rhythm of work and rest that honours the miracle of our bodies and nurtures human sustainability.
This isn’t just a call to slow down. It’s a call to protect what makes us who we are: human beings, not machines.
If you’re interested in reading the research, I have put the link below in the citation:
Sources: Jang, W. et al. (2025). Overwork and changes in brain structure: a pilot study. Occupational and Environmental Medicine. https://doi.org/10.1136/oemed-2025-110057
And as always, take care of yourself and those around you.
Until next time.
Nabeela
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