One Type of Sitting May Raise Dementia Risk More Than Another, Study Suggests

For years, researchers have believed that prolonged sitting could increase the risk of dementia. However, a new study suggests that the type of activity people engage in while sitting may be more important than the amount of time spent seated.

The study, published in the American Journal of Preventive Medicine, found that replacing mentally passive sedentary behaviors with mentally active ones was associated with a significant reduction in dementia risk.

Mentally active sedentary activities include:

Reading

Office work

Other tasks that keep the brain engaged

In contrast, mentally passive activities include:

Watching television

Low-engagement screen-based activities

A 19-Year Study

Researchers in Sweden analyzed data from more than 20,000 adults aged 35 to 64 over a 19-year period, from 1997 to 2016.

Participants reported their sitting habits, physical activity levels, and other lifestyle behaviors. Dementia diagnoses were later identified through national health and death records.

The findings showed that mentally active sedentary behavior was linked to a significantly lower risk of developing dementia compared with passive sitting activities.

What Researchers Say

Lead researcher Mats Hallgren emphasized that not all forms of sitting are the same.

“While all sitting involves minimal energy expenditure, it may be differentiated by the level of brain activity,” Hallgren said.

He added that how people use their brains while sitting appears to be a crucial factor in future cognitive health and may help predict the onset of dementia.

Public Health Implications

According to the researchers, sedentary behavior is a widespread but modifiable risk factor for many health conditions, including dementia.

The study suggests that:

Reading, writing, and other mentally stimulating activities may help protect brain health.

Passive behaviors, such as prolonged television viewing, may be associated with a higher dementia risk.

Staying both physically and mentally active is important as people age.

Important Caveat

The study was observational, meaning it identified an association between sitting habits and dementia risk but did not prove that passive sitting directly causes dementia.

Still, the findings add to growing evidence that mentally engaging activities—such as reading, learning new skills, solving puzzles, and other cognitive exercises—may support long-term brain health and help reduce the risk of cognitive decline.