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‘Physical stress’ at work linked to signs of brain aging and memory loss

Scientists have linked on-the-job stress to brain aging and memory loss for the first time, according to new research from Colorado State University. 

Their findings pertain to a very specific kind of stress. Through surveys about people’s most recent jobs, memory tests and scans of their brains they found brain changes and recall problems in people who found their jobs physically stressful. 

But, interestingly, the people who reported ‘physical stress’ at work did not necessarily have labor-intensive jobs.  

Yet mental stress at work was not associated with loss of volume in the hippocampus – a part of the brain critical to memory – or difficulty completing memory-based tasks. 

The researchers aren’t yet sure exactly why the perception of physical stress might lead to faster brain-aging, but their work could shed light on ‘the darker side of physical activity,’ lead study author Dr Aga Burzynska told 

Stress is well known to be destructive to the mind, but most research on its effects pertains to chronic stress, such as worry over finances, health issues, abusive relationships, or racism – not a person’s occupation. 

Brain scans revealed that people who said they felt ‘physically stressed’ at work had less volume in their hippocampus (highlighted), a region of the brain crucial to memory 

Scientists at Colorado State University (CSU) compared the size of a part of the brain largely responsible for memory, called the hippocampus, in older people with various occupations. 

The brain scans that they took showed that those whose most recent jobs had been physically stressful had smaller hippocampuses than those who reported mental stress at work. 

And those same physically stressed people struggled more with tasks that required them to recall information. 

Although the study subjects were cognitively healthy at the time of the research, the changes to the brains and recall abilities could be concerning signs that they will face faster declines earlier on compared to others.

The CSU researchers asked 99 people between ages 60 and 79 about their most recent jobs. 

Participants were quizzed on what their occupation was, their titles in those professions, how many years of education they’d had, their household incomes , the types of tasks they were required to do and they sorts of stress that they experienced on the job. 

That data was compared to MRI scans of participants’ brains and their performance on memory tasks. 

During the screening process for the study, none of the participants showed obvious signs of cognitive issues, had suffered any mental or neurological illnesses and had never (to their knowledge) had strokes.  

So in terms of brain structure, it could be expected that their brains would be somewhat similar. 

But both the scans and the memory tasks showed a marked difference in the minds of those who felt that their jobs were physically stressful. 

To be clear: these were not physical laborers. In fact, when asked to categorize the type of work they did, only one of the study participants would be considered a physical laborer. 

Most of the study subjects, who were recruited from a university town were well-educated, had relatively high incomes and were primarily ‘officials’ or managers. 

Lead study author Dr Aga Burzynska (pictured) says her findings don't implicate problems from physical activity - which is linked better brain health - but raise questions about how the perception of physical effort at a job might alter its effects on our brains

Lead study author Dr Aga Burzynska (pictured) says her findings don’t implicate problems from physical activity – which is linked better brain health – but raise questions about how the perception of physical effort at a job might alter its effects on our brains 

So the physical demands of their work were more likely to be lifting things, walking or standing, or even the physical taxation of sitting at a desk all day. 

‘If people perceive their work that their work requires excessive reaching or effort -even if they have not a physical job worse,’ it may lead them to describe their job as physically stressful, explained Dr Burzynska. 

The results of her study, published in Frontiers in Human Neuroscience, run counterintuitive to the generally accepted benefits of exercise for brain health. 

In fact, they run counter to Dr Burzynska’s own work. Her previous research followed in the footsteps of other research and verified that aerobic exercise is good for the brain. 

The new study is ‘the first evidence that leisure health behavior, such as phys activity, and what we experience at work have competing associations with our [brain health],’ she says. 

‘We overlook the effects – if aerobic exercise helps your brain, we think that then every [kind of] physical work will help brain. 

‘Well, perhaps not. That activity may not be aerobic,’ or might for other reasons not offer the same benefits as exercise in leisure time. 

Her new study even accounted for that and, once again, exercise in downtime was not linked to memory trouble or accelerated brain aging, as measured by shrinkage in the hippocampus. 

‘If you perceive that you have physical demand, it may be that that’s not good for the brain,’ said Dr Burzynska. 

‘Or maybe you perceive physical effort as unwelcome, if not objectively hard – that may reflect lifestyle or health views that we just didn’t capture. 

‘We have to dig deeper into what it means. Knowing how long we are staying in the workforce’ – about 40 years – ‘I think it’s very important to understand this.’ 


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