Long Working Hours May Reshape the Brain, New Study Warns — Why HR Leaders Should Take Note

As longer workweeks become the norm across industries, the health consequences of overwork are drawing serious attention. Beyond fatigue and burnout, new scientific evidence suggests that consistently working 52 hours or more per week could actually reshape the brain itself — with potential implications for memory, emotion, and decision-making.

📊 Study Highlights Structural Brain Changes

A recent study published in the journal Occupational and Environmental Medicine by researchers from Chung-Ang University and Yonsei University in South Korea analyzed data from 110 healthcare professionals as part of the Gachon Regional Occupational Cohort Study (GROCS).

Participants were divided into two groups — those who worked standard hours and those clocking at least 52 hours weekly, which is the maximum legal limit in South Korea. Using MRI scans and voxel-based morphometry (VBM), researchers observed striking differences in brain structure between the two groups. 

The long-hour workers showed:

• A 19% increase in volume in the left caudal middle frontal gyrus (involved in memory and attention).

• Volume increases in 17 other brain areas, including the superior frontal gyrus and insula, which are responsible for emotional control, self-awareness, and decision-making.

Researchers believe these changes may represent a neuroadaptive response to chronic stress — essentially, the brain physically adjusting to cope with the ongoing strain of overwork.

💬 Experts Warn of Long-Term Cognitive Impact

According to Professor Joon Yul Choi of Yonsei University, these alterations may be reversible if work-related stress is reduced, but recovery could take time.

“Overwork should be recognized as a serious occupational health risk,” said Choi.

Frank Pega from the World Health Organization (WHO), who has previously studied the global burden of overwork, described the findings as “important evidence” linking long working hours to both physical and mental health consequences. However, he noted limitations due to the small, specific sample group and urged for broader research across industries.

Similarly, Jonny Gifford from the Institute for Employment Studies (UK) said the study provides “physiological proof of what many already suspect — that overwork affects the brain.”

🧩 What This Means for HR and Workplace Policy

This study underscores an urgent call to action for HR professionals and business leaders:

• Reevaluate workload expectations and ensure employees aren’t consistently exceeding healthy limits.

• Encourage regular breaks, flexible scheduling, and mental health support programs.

• Promote work-life balance through policies that discourage after-hours work.

• Leverage data from employee engagement and wellness surveys to detect early signs of overwork.

As organizations worldwide face growing productivity pressures, these findings serve as a stark reminder — long working hours don’t just drain employees; they may be changing their brains.

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💡 HR Insight:

Forward-thinking organizations are now shifting focus from “hours worked” to outcomes delivered. Sustainable productivity begins with healthy brains — not exhausted ones.