This habit, deeply rooted in many professional cultures, is gradually undermining personal wellbeing – it feeds chronic stress and weakens mental and physical health, to the point of disrupting the very functioning of the brain.
These are the findings of researchers from Chung-Ang and Yonsei Universities in South Korea. Analysing the effects of overwork on the human brain, they conducted a study involving 110 professionals, mostly from the healthcare sector.
The participants were divided into two groups: the first comprised 32 people working 52 hours or more a week; the second, 78 people with standard working hours. Brain imaging revealed clear differences in grey matter volumes, particularly in areas associated with executive function and emotional regulation.
The results are striking: the scientists found a significant increase in grey matter in certain brain regions as a possible physical effect of burnout. The middle frontal gyrus, which plays a role in attention, memory and advanced cognitive functions, showed a 19% increase in volume in the most overworked workers.
Other areas were also affected, such as the superior frontal gyrus, involved in planning and decision-making, and the insula, essential for self-awareness, emotional management and interpreting social context.
The experts state in a press release that “the observed changes in brain volume may provide a biological basis for the cognitive and emotional challenges often reported in overworked individuals”.
What exactly does this mean? For now, the answer remains unclear. “While the results should be interpreted cautiously due to the exploratory nature of this pilot study, they represent a meaningful first step in understanding the relationship between overwork and brain health,” the researchers say.
For the time being, it is impossible to determine whether these changes are directly caused by overwork, whether they pre-exist it, or whether they are reversible.
Although the study sample remains small – consisting exclusively of South Korean healthcare workers – the results form part of a worrying trend. In 2021, a joint study by the World Health Organization and the International Labour Organization attributed over 745,000 deaths a year to overwork.
The link between long working hours and cognitive decline is now well documented, and at a time when trials of the four-day week are multiplying, these conclusions serve as a wake-up call.
“The results underscore the importance of addressing overwork as an occupational health concern, and highlight the need for workplace policies that mitigate excessive working hours,” the researchers caution.
Concrete measures – legislation, public policy, time limits – therefore need to be considered to protect workers in the long term.