Exercise Done At Work May Increase Dementia Risk

Regular exercise has long been linked to decreased dementia risk. A 2022 paper found that just 3,800 steps a day may reduce your likelihood of developing dementia by 25%, with increasing benefits up to 9,800 steps, for instance.

And strength training has been shown to help protect the parts of the brain particularly vulnerable to Alzheimer’s, too.

The NHS recommends 150 minutes of moderate-intensity activity, 75 minutes of higher-intensity exercise, or a combination of both every week to help us see the benefits of movement.

But a new paper has found that why we reach those goals might matter a lot more than we thought when it comes to dementia risk.

The paper, published in the journal The Lancet, looked at data from 74 studies, involving 4.2 million participants overall.

These participants were from 30 different countries and were aged between 45 and 93. On average, researchers tracked them for a decade.

After analysing this data, the study authors found that exercising more often was linked to a 24% lower likelihood of developing dementia.

But that only seemed to be the case for leisure-time activity and (maybe) housework.

Those who exercised a lot due to physically demanding jobs appeared to face a 20% higher dementia risk, while active commuting (like cycling to work) seemed associated with a moderately higher risk too.

Researcher Natan Feter, the study’s first author, said: “The findings challenge the long-held assumption that ‘every move counts’ for brain health.”

The authors of this meta-analysis suggested that this higher risk may be linked to factors common in very physical workplaces, rather than the movement itself.

These factors might include stress, uncontrolled noise (hearing loss has been associated with a greater likelihood of developing dementia), air pollution, and hazardous working conditions.

This phenomenon – sometimes called “the activity paradox” – has been seen in other research, too.

Some studies have found that work-related exercise may raise your risk of some health conditions, like heart problems, long-term sickness and related absences, and even an increased risk of death, although leisure-time activity lowers those same risks.

And a 2021 paper found that even the burnout-reducing potential of leisure-time activity might disappear when someone has a very physically demanding job.

Pollution could also be a factor involved in why those engaging in ‘active commuting’ might experience a heightened risk. As the Alzheimer’s Society says: “Exposure to a high level of air pollution increases a person’s risk of developing dementia.”

Professor David Raichlen, who led the research team, said that we should therefore be considerate when issuing advice telling people to “move more” without considering the context of activity.

“When it comes to protecting the brain, the context of physical activity may matter just as much as movement itself,” he said.

“Improving access to safe parks, walking trails and recreational facilities, ensuring people have adequate leisure time for exercise, and reducing harmful workplace exposures may ultimately prove as important as promoting physical activity itself.”