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Mild Cognitive Impairment

Watching (Too Much) TV Is Bad for Adults, Too

Even moderate TV time is linked to cognitive decline.

Key points

  • Studies show that moderate TV watching can lead to greater cognitive decline over 10-20 years. Exercise also does not mitigate these effects.
  • According to research, TV watching does not increase the risk of dementia.
  • Strategies to slow mental aging include being social and engaging in stimulating hobbies.
Glenn Carstens-Peters/Unsplash
Source: Glenn Carstens-Peters/Unsplash

Parents worry about whether letting their children watch TV (or play video games or stay glued to social media) will hurt their grades and mental development.

The clearest danger is that TV time could substitute for physical exercise, in-person socializing or reading, or other hobbies that help children develop.

Now new research suggests that adults may lose cognitive functioning if they maintain a TV habit.

One new study was based on surveys of 10,700 adults in the United States between the ages of 45 and 64. In the late 1980s and again in the early 1990s, they reported on whether they rarely, sometimes, or often watched television. Nearly 6,500 gave similar answers at both survey points, suggesting that their TV habits were stable.

In the late 1990s and then between 2011 and 2013 that group took tests of their working memory, and speed at language tasks.

The researchers concluded that those who said they sometimes or often watched TV over the years had a 7 percent greater decline in their performance on the tests, compared to people who rarely watched TV. However, the TV watchers didn’t seem to have a higher risk of dementia. Also, how much exercise they got didn’t seem to affect the results.

To see how TV watching affected the brain, a second study gave just over 1,600 participants brain scans. People usually have better cognitive skills if they have more gray matter, a darker tissue. This study had a scary finding: If you reported watching TV even moderately, a decade later you had less gray matter than people who rarely watched TV.

In a third study, researchers looked at data for about 600 people who had an average age of 30 when the study began and 50 at follow-up. Over two decades they reported every five years about how many hours of TV they watched each day in the previous year. For most of the participants, their watching habits didn’t change much.

When they underwent brain scans in midlife, those who reported watching more TV over the 20 years had less gray matter. For every extra hour of watching, they lost about as much gray matter as people normally do during midlife.

Another way of looking at this information: TV doubled their expected cognitive decline. Again, being physically active didn’t make a difference.

How can you actually use this? There is some good news here. If you’re worried about dementia, it appears from this research that watching TV won’t increase your risk, at least not enough to emerge in these large studies. It also suggests that being physically active isn’t the only way to keep your gray matter. Although this research didn’t pin down which sedentary activities were linked to more gray matter, other studies show that you have many options.

Is all TV bad? Some TV shows are complex and will keep you mentally stimulated. If you have fun or revealing conversations with your friends and family about TV shows, that’s a big plus: Social connection is as good for you as exercise. Relaxing is important, too.

But if you can cut back on TV in favor of interesting or social hobbies, you might stay a bit sharper into your later years. Reading, writing, doing crossword puzzles, playing board or card games, engaging in group discussions, and playing music all count. In one study, mentally intact people in their 70s and 80s who said they did those activities frequently lowered their chance of impairment by half. I turn to cooking and crafts for fun stimulation.

Lily Rum/Unsplash
Source: Lily Rum/Unsplash

How to protect yourself from mental aging

Exercise is still a good bet to avoid the illnesses of later life, including cognitive decline and dementia. It may be helpful even for people who already have memory problems.

A diet with plenty of fish, whole grains, and vegetables will help.

Heavy drinking boosts your dementia risk.

Getting the right amount of sleep is important.

Stay connected to others.

Stimulate your mind. A tricky game of cards will keep you alert! It’s not too late, by the way, according to research with Scottish elders. What you do in your 70s can help you in your 80s.

A version of this story appears on Your Care Everywhere.

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