Bad Combination for Later Life Brain Health: TV + Sitting

By Lorra Garrick | Last updated 08/26

The TV has long been known as the “idiot box.” Now there’s research that shows it really can negatively affect brain health later in life.

A study published in Alzheimer’s and Dementia: Journal of the Alzheimer’s Association found that people who reported watching TV “very often” during midlife later had smaller volumes in several brain regions involved in memory.

They also had smaller frontal and occipital lobes and more white matter damage.

These brain changes have been associated with aging, stroke risk, cognitive problems and dementia.

The researchers say the issue may not simply be how long someone sits, but what they are doing while sitting.

Perhaps you’ve heard of the “sitting disease,” also dubbed “the new smoking,” because excessive sitting has been linked to chronic illness.

Now research is looking at what people actually do with all that chair time.

TV Watching and Brain Health

The study followed about 1,700 adults who were 53 years old on average.

They were participants in the long-running Atherosclerosis Risk in Communities Study, which began in the late 1980s.

Participants reported how often they watched the tube during their free time.

Their choices ranged from “never/seldom” to “very often.” They also reported how much of their workday they typically spent sitting.

More than two decades later, researchers used MRI scans to examine their brains.

People who said they watched TV very often showed several structural differences compared with those who rarely watched it.

Frequent TV viewers had smaller volumes in brain regions associated with early Alzheimer’s disease.

They also had more white matter hyperintensities. These are signs of small blood vessel disease in the brain and have been associated with cognitive decline and dementia.

Their frontal and occipital lobes were also smaller. The frontal lobes are involved in planning, decision making and other executive skills. The occipital lobes are important for processing visual information.

The researchers continued to see these differences after accounting for factors including exercise, diabetes, body mass index, smoking and alcohol use.

This suggests that excessive TV time is an independent risk factor for structural changes in the brain that may lead to cognitive decline.

Why Sitting in Front of the TV May Be Different

One interesting part of the study was that sitting itself didn’t appear to explain the findings.

In fact, people who spent much of their workday sitting tended to have larger frontal and occipital lobes and fewer white matter hyperintensities than people who spent their sitting time and watching TV.

That could mean that all sedentary activities aren’t equal when it comes to brain health.

A person sitting at a desk may be concentrating, solving problems, reading or interacting with other people.

Watching TV, on the other hand, can involve relatively little mental effort.

The researchers suggest that this difference in mental stimulation could help explain the results.

TV Effects Appeared Stronger in Men

The researchers also noticed a difference between men and women.

When they separated the MRI results by sex, most of the brain changes associated with TV viewing and sitting at work were found in men.

That doesn’t prove that men are more vulnerable to the effects of the “idiot box,” but it does raise questions that future research will need to answer.

Limitations of the Study

First off, it didn’t distinguish among types of TV shows, e.g., soap operas, sitcoms, medical dramas, action movies, news and educational documentaries.

The study also didn’t look at the variable of spending significant periods of TV time while walking on a treadmill or using other cardio equipment.

In addition, viewing was based on participants’ own reports rather than direct measurements.

Plus, researchers didn’t have brain scans from the beginning of the study, making it harder to determine exactly how brain structure changed over time.