April 8, 2026
Studies show that sitting and other sedentary behaviors are bad for our overall health, including the health of our brain. But what we do when we sit can make a difference when it comes to brain health, according to a new report.
The study, in the American Journal of Preventive Medicine, found that not all sitting is the same. Adults who sat while remaining mentally passive, exemplified by the “couch potato” parked in front of the TV, faced a higher risk of dementia years down the road. Those who engaged in mentally stimulating behaviors while sitting, on the other hand, such as reading, working on the computer or playing a challenging game or puzzle, had a lower risk of dementia later in life.
“While all sitting involves minimal energy expenditure, it may be differentiated by the level of brain activity,” said the study’s lead author, Mats Hallgren, of the Karolinska Institute in Sweden. “How we use our brains while we are sitting appears to be a crucial determinant of future cognitive functioning and may predict dementia onset.”
For the study, Dr. Hallgren and his colleagues analyzed medical and behavioral data from 20,811 men and women who were part of several large health databases in Sweden. They ranged in age from 35 to 64 and lived in some 3,600 towns and villages across Sweden.
At the start of the study, participants completed surveys about their typical physical activities, including how much they sat throughout the day. The surveys also contained detailed information about how they spent their sedentary time.
Researchers tracked participants for about 19 years. During that time, 569 developed Alzheimer’s disease or another form of dementia.
Analyses revealed that mentally passive sedentary behaviors were associated with a higher risk of developing dementia, while staying mentally engaged while sitting or reclining was tied to a lower dementia risk. Substituting one hour per day of passive sedentary behavior with the same amount of mentally active sedentary behavior was associated with a 7 percent reduction in dementia risk. Each additional hour per day of mentally active behavior was associated with a 4 percent lower risk for developing dementia.
The study showed only an association between passive sitting and dementia risk and cannot prove cause and effect. But the study was large and given that most adults spend nine to 10 hours a day sitting, the findings could have broad implications. Previous research has shown that extended, uninterrupted sitting is a risk factor for cardiovascular disease, type 2 diabetes, and depression, all of which are tied an increased risk of Alzheimer’s disease.
“Our study adds the observation that not all sedentary behaviors are equivalent,” Dr. Hallgren concluded. “Some may increase the risk of dementia, while others may be protective. It is important to remain physically active as we age, but also mentally active, especially when we are sitting.”
Next time you hit the couch or armchair, think twice before flicking on the latest reality show. Consider watching an educational program on public television, reading a book or magazine, playing a word game on your computer tablet, or listening to classical music. All may be better for your brain in the long term.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Andre O. Werneck, PhD; Michael J. Wheeler, PhD; David W. Dunstan, PhD; et al: “Mentally Active Versus Passive Sedentary Behavior and Risk of Dementia: 19-Year Cohort Study.” American Journal of Preventive Medicine, March 26, 2026
