What too much TV really does to your brain and how much is too much

Next time your favorite streaming service asks if you’re still watching, you might want to think twice before hitting “Yes.”Ever since TVs became fixtures in American homes, doctors — and plenty of worried parents — have warned that too much screen time could take a toll on our bodies, brains and social lives.But exactly how much truth is there to all those warnings? Researchers have spent decades investigating what happens to our brains and bodies when we spend too much time glued to the screen.Here’s what they’ve found — and how much TV may be too much.Long hours in front of the TV during young adulthood may be linked to poorer cognitive function later in life.A 2015 study followed 3,247 people ages 18 to 30 for 25 years to investigate the effects of TV viewing and physical activity on midlife cognition.Rearchers administered three cognitive tests to the participants, assesings processing speed, executive function and verbal memory.The researchers found that watching more than three hours of TV a day and having low levels of physical activity in early adulthood were associated with worse executive function and processing speed in midlife.The one exception? Heavy TV viewers did not perform worse on tests of verbal memory.The findings were among the first to suggest that these behaviors could be important targets for preventing cognitive aging before middle age — but the researchers cautioned that the study could not prove that TV watching or physical inactivity actually caused cognitive decline.In a 2023 study, researchers found that people who watched a moderate amount of TV — two to three hours a day — or a high amount — more than three hours a day — had a higher risk of dementia than those who watched zero to one hour daily.Those who watched the most TV and also had with family history of dementia had a 42% higher dementia risk, compared with a 30% higher risk among those without a family history.But these studies come with an importa...