Long working hours might not just be bad for you, they could also be altering the structure of your brain, a new study suggests.
The research, published Tuesday, found “significant changes” in the brains of people who were overworking, which is a combination of physical and emotional overexertion, as well as a lack of rest.
The research was conducted by two scientists at South Korea’s Chung-Ang University and Yonsei University, who followed 110 healthcare workers classified into “overworked” and “non-overworked” groups.
In South Korea, where 52 hours of work per week is the legal upper limit, overworking has become a public health concern.
The overworked group, clocking 52 hours or more each week, consisted of 32 people who were on average younger, in employment for less time and more highly educated in comparison to those working standard hours.
By comparing data from a different study and MRI scans, the researchers were able to use a neuroimaging technique to analyse the workers’ brain volume.
The technique allowed them to identify and compare differences in levels of gray matter in different regions of the brain, while the application of atlas-based analysis meant they could identify and label structures in brain scans.
“People who worked 52 or more hours a week displayed significant changes in brain regions associated with executive function and emotional regulation, unlike participants who worked standard hours,” researchers said in a press release.
Areas of the brain that showed an increase in volume include the middle frontal gyrus, which plays a major role in cognitive functions, attention, memory and language-related processes, as well as the insula, which is involved in emotional processing, self-awareness and understanding social context.
Researchers believe their findings suggest a “potential relationship” between having an increased workload and changes in these parts of the brain, providing a biological basis for the cognitive and emotional challenges reported by people who are overworked.
Joon Yul Choi, coauthor of the study and an assistant professor at Yonsei University’s Department of Biomedical Engineering, told CNN that these changes might be “at least in part, reversible” if environmental stressors are reversed. Still, returning to your brain’s baseline state could take much longer.
‘Important new evidence’
Previous research has also found evidence of the negative health impacts of long working hours. In 2021, joint research from the International Labour Organization (ILO) and the World Health Organization (WHO) estimated that overworking led to more than 745,000 deaths in a year. Long hours have also been found to raise the risk of diabetes in women and contribute to a decline in cognitive ability.
While these behavioral and psychological consequences of overwork are well-known, the underlying neurological mechanisms and changes in anatomy are less understood, the study explained.
Frank Pega, who led the WHO-ILO 2021 study, told CNN that these latest findings constitute “important new evidence” that could help better understand how long working hours “radically” impact the physical health of workers.
Pega, a WHO technical officer who was not involved in this latest study, said the research supports WHO-ILO’s findings that “long working hours contribute the largest burden of disease of all occupational risk factors identified so far.”
However, the study’s small sample size and focus only on healthcare workers in South Korea makes it hard to generalize its results. “More studies in different populations are needed,” said Pega.
“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,” said the researchers.
As for anyone stuck working long hours? Now you might have a scientific basis to cut down on your time at work.
“Governments, employers, and workers can all take actions to protect workers’ health from long working hours,” advised Pega, citing laws, regulations and policies that can ensure healthy work hours.
“The results underscore the importance of addressing overwork as an occupational health concern,” said the study’s authors.
Jonny Gifford, principal research fellow at the Institute for Employment Studies in Brighton, England, who was not involved in the study, told CNN that the research “confirms some physiological reasons that working long hours affects our wellbeing.”
“The use of brain scanning equipment to give neurological explanations gives powerful new evidence linking overwork with structural changes in parts of the brain involved in executive function and emotional regulation,” he said.
“It’s a small study of 110 healthcare workers in Korea, but because it is based on robust neurological measures and concerns fundamental mechanisms (overwork and fatigue) that can affect anyone, the central findings are widely relevant,” Gifford added.
The study was published in the journal of Occupational and Environmental Medicine.
CNN’s Jack Guy contributed to this report.
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