Many studies have found sitting for extended periods is unhealthy, increasing the risk for dozens of chronic conditions, from cancer and diabetes to cardiovascular disease. But is sitting cross-legged particularly harmful?

Naresh C. Rao, a doctor of osteopathic medicine and U.S. Olympic water polo team physician for the 2016 Summer Games, tells the Wall Street Journal the answer to that question is complicated.

Some studies have suggested sitting cross-legged can lead to varicose veins. But Rao, who is clinical instructor at NYU Langone Medical Center in New York City, says the condition is more closely linked to genetics, age, and obesity.

He also notes there is an association between prolonged sitting and an increase in blood pressure among people who already suffer from hypertension. “But sitting cross-legged doesn’t lead to developing hypertension,” he tells the WSJ.

But crossing your legs can put pressure on your pelvis and lead to knee pain.Rao explains that the top knee puts pressure on the lower knee, while the pelvis is rotated and strained.

The most common cause of knee pain, Rao says, is keeping your knees in a misaligned position for a long period of time. “So I wouldn’t say you’re going to end up with knee pain, but if you already have knee pain, that twisted and bent position will make it worse,” he explains.