Netflix Binging In Your 20s Could Have One Major Health Consequence

TV is literally rotting your brain.

Sitting on your couch marathoning the entire first season of "Narcos" might seem like a harmless enough way to spend a weekend. But according to new research, your runaway TV addiction could have some major negative health consequences down the road.

A new long-term study shows a worrisome link between leading a sedentary, screen-heavy lifestyle in young adulthood and experiencing cognitive decline 25 years later. This is likely due, in large part, to the fact that watching television is a sedentary activity, and physical inactivity is a known contributor to cognitive decline.

For the longitudinal study, which was published Dec. 2 in the journal JAMA Psychiatry, researchers asked 3,247 white and African-American young adults between the ages of 18 and 30 to answer questions about their television viewing and exercise habits (measured based on time and intensity of physical activity) during a series of regular check-ins over the course of the 25-year period of study.

At the end of that timeframe, the researchers evaluated the participants' cognitive function through tests of processing speed, executive function and verbal memory.

Roughly 10 percent of the participants reported watching three or more hours of TV each day for at least two-thirds of the check-ins. And this group was significantly more likely to perform poorly on the tests of cognitive function. The 16 percent of participants with low physical activity ratings were also more likely to perform poorly on some of the tests.

Unsurprisingly, those at the greatest risk of cognitive deterioration were both heavy TV viewers and had low levels of physical activity. They were more than twice as likely to perform poorly on the tests. These participants exhibited slower processing speed and worse executive function, but their verbal memory remained intact, the study's authors noted.

“TV watching may also be less cognitively engaging than other activities or could also be related to other behavioral patterns such as less social activity or poor diet.”

"It may be that TV watching is a sedentary behavior that increases cardiovascular risk factors," Dr. Tina Hoang, a research associate at Veterans Health Research Institute in San Francisco and one of the study's authors, told The Huffington Post. "TV watching may also be less cognitively engaging than other activities, or could also be related to other behavioral patterns such as less social activity or poor diet."

Research has drawn a clear connection between physical inactivity and cognitive decline. Weight gain in older adults (often the result of a sedentary lifestyle) is associated with shrinkage in brain areas associated with memory. Still, there may be something specific about television: A recent study also linked binge-watching television to loneliness and depression.

That study's author, University of Texas psychologist Yoo Si Hung, told HuffPost, "Even though some people argue that binge-watching is a harmless addiction, findings ... suggest that binge-watching should no longer be viewed this way."

The good news is that you don't necessarily have to give up the latest season of "Transparent." Getting exercise -- even just walking for 30 minutes a day -- or breaking up your TV viewing into shorter chunks could make a difference.

"Physical activity is a great way to start taking care of brain health, even for younger adults," Hoang said. The neurological benefits of exercise include improved learning and memory, lower levels of stress, anxiety and depression, and enhanced brain function.