Watching TV Linked to Dementia, but Computer Use Is Good

Before they plop on the couch to engage in some "leisure-time sedentary behaviors," adults over 60 may want to pay attention to a recent study linking increased dementia risk to watching TV. In short, per the Washington Post, "those whose time sitting was primarily spent watching television had a 24% increased risk for dementia." But wait, that's not the only takeaway. The peer-reviewed study, published in the Proceedings of the National Academy of Sciences, also found that computer use was associated with a 15% reduced risk of dementia. The simple explanation is that nothing beats television when it comes to cognitively passive activities; by contrast, using a computer requires at least some level of cognitive engagement, not unlike the antiquated activity known as reading.

Researchers tapped the UK's Biobank to build the study cohort of some 146,651 individuals, whom they tracked for about 12 years, controlling for numerous lifestyle and demographic variables along the way, according to MD Edge. High use of TV—at least 4 hours per day—correlated to the highest risk of dementia, while as little as 30 minutes of computer use yielded reduced risk. "What we do while we’re sitting matters," study lead David Raichlen noted, per Science Daily. "This knowledge is critical when it comes to designing targeted public health interventions aimed at reducing the risk of neurodegenerative disease from sedentary activities."

In a slight twist compared to previous studies, researchers found that participants’ level of physical activity did not affect their odds of developing dementia if in fact they also watched a lot of TV. As for why computer use is beneficial, one notable neurologist—Dr. Andrew E. Budson, who was not associated with the study—explained to MD Edge that even light cognitive activity on the computer engages important parts of the cerebral cortex. While Dr. Budson emphasized that physical activity is always preferable to sedentary behavior, he added, "This is one of the first times I've been convinced that even when the computer activity isn’t completely new and novel, it may be beneficial." (More dementia stories.)