Want to live 5 years longer? Stop watching TV! Or, at least, stop sitting while you watch. That’s the upshot of two huge new studies involving more than 800,000 adults over several years.

Researchers found that for every single hour of TV people watched after age 25, the person’s life expectancy was shortened by 20 minutes. That’s twice as much time as you lose by smoking a single cigarette. Which means, if you watch 6 hours of TV on most days, you’ll live about 5 years less than someone who watches no TV. And that’s true whether you exercise regularly, or not.

Researchers discovered that we adults spend an average of 60% of our time sitting. And study participants who sat the most were twice as likely to develop diabetes, 150% more likely to have heart disease and 50% more likely to die prematurely, no matter how active they were otherwise.

What’s the deal here? Researchers say that when we sit for extended periods, our skeletal muscles become incredibly relaxed, which means, we’re using a lot less energy, especially in our leg muscles. But sitting and watching TV is WORSE than plain ol' sitting - because it puts us into a trance-like state. And slows down our metabolism more than sitting while reading, surfing the web, sitting in traffic, or playing solitaire. The only activity that does less for our metabolic rate is sleeping!

So, what can we do? Simple. Watch fewer than 2 hours of TV a day. That’ll put you in the “lower-risk” group. Also, add more movement into the rest of your day. Say, by standing whether you’re on the bus or the assembly line – even during meetings, coffee breaks, and when you’re on the phone.