That’s a possibility. In a recently published study of this issue, researchers at the University of California, San Francisco investigated how excessive TV screen time might affect the brain by following more than 3,000 young adults for 25 years. Every 5 years the investigators asked the study participants how much television they watched and periodically questioned them about their exercise habits. When the participants joined the study, all were between the ages of 18 and 30. At the end of the 25 years, when most were in their 40s or 50s, they took three tests designed to evaluate information processing, verbal memory and executive function, the skills that help us plan, organize and solve problems. Results showed that those who watched 3 hours or more of television daily and performed little exercise were twice as likely to score poorly on the tests as those who watched less TV and were more physically active.
While that’s not a good outcome, the study didn’t determine whether the poor results were due to inactivity or too much time watching television. And because the researchers hadn’t been able to test the participants’ cognitive function when they were young, we don’t know for sure what influence their baseline scores might have on the test results.
The study also doesn’t tell us what kind of programs the individual study subjects were watching. While some TV programs can be mind numbing, others can be cognitively stimulating – you actually can learn something from them.
We know from earlier research that exercise is good for the brain and may even protect older people from Alzheimer’s, so it is possible that inactivity was the culprit here. Another study from the University of Texas at Austin, published in 2015, found that people most likely to binge-watch were lonely and depressed, and were attempting to distract themselves from negative feelings. While the cognitive gap between those in the study who watched a lot of television and didn’t get much exercise and those who watched less and exercised more was significant, it wasn’t wide enough to affect daily life. However, the researchers expressed concern about further and more rapid cognitive declines with age among those who did poorly on the tests.
Whatever the effects of television on the brain may be, we already know that being physically active is better for your overall health – and your brain – than spending hours sitting in front of the TV (or anywhere else).
Andrew Weil, M.D.
Tina D. Hoang et al, “Effect of Early Adult Patterns of Physical Activity and Television Viewing on Midlife Cognitive Function.” JAMA Psychiatry, December 02, 2015. doi:10.1001/jamapsychiatry.2015.2468