It's after midnight, well past your normal bedtime, and you're about to start watching your third straight episode of that police drama or classic comedy while sitting on the couch with a blanket.
Sounds like a cozy way to wind down the night. Just try not to do it for too long and too often, said Andrea LaCroix, distinguished professor and division chief of epidemiology at the University of California, San Diego.
"Is binge-watching bad? I'd like to say 'No, it's not bad,'" LaCroix said. "If you care about the cardiovascular effects on your long sitting, no matter what reason you're sitting for, it's just important to figure out the habit, or create the habit, of moving every now and then."
A January article in the European Journal of Preventive Cardiology that reviewed three previous studies related to TV viewing found a similar conclusion: Longer periods of viewing may increase the risk of developing a blood clot.
Researching the health impact of binge-watching is so new that a 2020 article in the International Journal of Environmental Research and Public Health that reviewed 28 earlier studies found no consensus definition of the term, other than "watching multiple episodes of a TV show in one sitting."
The key word might be "sitting," or doing too much of it. Blood clots can form when something slows or changes the flow of the blood.
After about an hour of sitting, blood and fluid start to pool in the legs, said Bethany Barone Gibbs, an associate professor at the University of Pittsburgh who researches sedentary behavior and physical activity. Pooling leads to reduced flow and circulation, so blood pressure starts to rise to compensate to return blood back to the heart.
LaCroix was an author of a 2019 study in the American Heart Association journal Circulation that found both high amounts of sedentary time and longer durations of such time were associated with increased risk of cardiovascular disease in older women.
Another 2019 study in the Journal of the American Heart Association found that people who watch little or no TV and are highly active live about two and a half years longer free of coronary heart disease, stroke and heart failure than those who often watched TV and weren't active.
But viewing habits aren't likely to change anytime soon given the proliferation of streaming services and allure of all-you-can-view menus of multiple TV seasons. Streaming giant Netflix said in 2016 that members prefer to finish an entire season in one week instead of watching one episode a week.
More people turned to streaming when stay-at-home guidelines were issued at the outset of the COVID-19 pandemic two years ago. According to a survey by Nielsen, the audience measurement company, the average cumulative amount of time people in the U.S. spent streaming each week during the second quarter of 2020 was 142.5 billion minutes, up from 81.7 billion minutes during the same period in 2019.
The solution, Gibbs said, is getting up and taking a break.
"You don't have to get rid of your TV. You just have to break up your television watching," Gibbs said. "Stand up and do the dishes, put a load of laundry away or pack your lunch. Do something!"
Researchers are studying the ideal amount of time to stay seated before taking a break. Gibbs suggested walking for a few minutes once an hour and setting reminders through a smartwatch or fitness tracker.
She also recommended setting a time to turn the screen off to preserve a good night's sleep and turning off the option on your streaming service to automatically play the next episode.
LaCroix recommended standing for intervals while watching TV or other typically stationary activities like talking on the phone. Drinking water or a cup of tea while watching also might help because eventually you will need to break up the binging with a trip to the bathroom.
"A lot of times, you get up and start doing something and you don't want to sit down right away," LaCroix said. "The hardest part is just changing posture."
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