Sitting in economy class on a long flight doesn’t put you at higher risk of blood clots.

But sitting next to the window might.

That’s the finding of a new study on deep-vein thrombosis — clots that form in leg veins and can kill if they travel to the lungs.

The condition has been dubbed “economy class syndrome” based on the theory that the lack of leg room in the back of a plane might be a factor.

But researchers from the American College of Chest Physicians said whether passengers fly coach or roomier first-class doesn’t make a difference.

The real cause is not moving around during a long-haul voyage. Sitting next to the window seems to keep people in their seats because they’re reluctant to disturb their row mates.

The doctors note that most healthy people don’t have to worry about the clots. The risk of developing one on a long flight is only about 1 in 500.

They recommend taking a walk down the aisle every hour or two and flexing and extending the ankles while seated.

(Source: NY Daily News)