TV binge-watching might be bad for your brain.

Young adults who spend a lot of time as couch potatoes tend to lose some brain power in middle-age, according to new research.

The study, published this week in JAMA Psychiatry, discovered the link between too much screen time and cognitive decline down the road.

Over a span of 25 years, researchers from the University of California, San Francisco tracked the television viewing and exercise habits of 3,247 adults who were between 18 and 30 when the study started. At the end, the scientists tested the participants' brains' processing speed, executive function and verbal memory.

The results were mind-boggling.

Those who averaged at least three hours of TV a day were far more likely to test poorly. And those binge-watchers who also reported getting very little exercise were more than twice as likely to score low on the cognitive tests.

It's unclear what exactly is behind the connection between excessive TV watching and brain drain — whether it's spacing out in front of the TV that's the problem or all that sitting around. Stay tuned for more research on that.

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