Viewing TV for more than 3.5 hours per day is associated with cognitive decline in older age
It’s hard to imagine a world today without television and its immediate descendants like Netflix and Disney+. Considerable research has explored the effects of television on children, whose minds tend to be perceived as more susceptible to negative influence. In many ways, however, they are more resilient, while impaired cognition in the aging adult population is associated with increased all-cause mortality.
To better understand the extent to which television participates in cognitive decline in aging adults, researchers delved into data provided by the English Longitudinal Study of Aging (ELSA), focusing on roughly 3,600 adults aged 50 or above.
Unlike more creative pastimes that stimulate the brain and require active participation, or passive-stimulus pastimes like reading a book, television combines “strong rapidly-changing fragmentary dense sensory stimuli with passivity from the viewer.” This unique combination has been accompanied by conflicting results in previous studies, although links have been drawn with cognitive impairment, reduced memory, and increased risk of Alzheimer’s.
Previous research has used television as a proxy for sedentary behavior, confounding these related but distinct phenomena, and focused on excessive television watching (e.g. 6+ hours/day). To paint a picture that’s both clearer and more in line with television habits of the average aging adult, the authors controlled for sedentariness and used a more modest metric of 3.5 hours per day.
On top of self-reported television habits, ELSA contains data from frequent verbal memory tests, which the authors used as a measure of cognition. The study demonstrates that 3.5 hours of television results in reduced verbal memory, with a dose-response relationship (greater hours of television lead to poorer verbal memory). Furthermore, stronger initial verbal memory was associated with greater decline at follow-up. Finally, the authors found an important threshold effect, such that 3 hours of television was not associated with poorer cognition, but 3.5 hours was.
Studies like this one help us to better understand how television affects our brains as we age, and can help safeguard against negative effects. The fact that the authors were able to define a threshold under which television viewing was found considerably less harmful is an important takeaway for the aging population.
The study, “Television viewing and cognitive decline in older age: findings from the English Longitudinal Study of Ageing“, was authored by Daisy Fancourt and Andrew Steptoe.
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