Too much TV may put your brain at risk, but not for the reason you think

Brittany A. Roston - May 20, 2021, 7:38pm CDT
Too much TV may put your brain at risk, but not for the reason you think

If you’re a couch potato now, the habit may be putting you at risk of cognitive decline later in life. That’s according to three new studies published by the American Heart Association, which found that moderate to high television consumption in midlife was linked to lower gray matter volumes and worse cognitive decline in older age.

The research defines midlife as ages 45 to 64 years; it likewise classifies TV watching as sedentary behavior, a lifestyle that is generally associated with worsening brain health in one’s elderly years. A person’s cognitive performance, such as one’s ability to think and remember things, naturally decreases with age.

This new body of research evaluated whether being sedentary in midlife may speed up the rate of cognitive decline; it based the evaluation on self-reported data about TV watching habits. The responses were split up into groups: low TV watching, meaning rare or never watches television, as well as medium (sometimes), and high, meaning very often.

Two different studies were conducted on this, one finding that moderate and frequent TV watching was associated with a 6.9-percent increase in cognitive decline risk over the next 15 years. However, frequently watching TV wasn’t linked to an increased risk of developing dementia.

The second study, which included MRI brain scan data, linked moderate and frequent TV watching with reduced deep gray matter volume more than a decade later. The impact was particularly notable in people who consistently reported moderate and frequent TV watching over the years compared to people who rarely watched TV.

The association between TV watching habits and brain health later in life wasn’t just due to the sedentary nature of television, however, with the researchers noting that other sedentary activities that stimulate the mind — such as playing board games — aren’t linked to a greater risk of dementia.

Ryan Dougherty, M.S., Ph.D., the lead author of one of the studies, explained:

In the context of cognitive and brain health, not all sedentary behaviors are equal; non-stimulating sedentary activities such as television viewing are linked to greater risk of developing cognitive impairment, whereas cognitively stimulating sedentary activities (e.g., reading, computer and board games) are associated with maintained cognition and reduced likelihood of dementia. Considering the contextual differences in varying sedentary behaviors is critical when investigating cognitive and brain health.

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