If you wear high heels regularly, it may not come as a surprise to learn that they’re not great for your feet.

Researchers had the chance to study a four-year flight attendant training program in Korea, which required women to wear heels to class. They found that although new heel wearers’ lower-leg muscles gained strength at first, the women ultimately faced a higher risk of ankle instability, weakness, and balance problems.

The Cleveland Clinic recommends that women switch to shoes with a lower profile, saving their high heels for special occasions, and that women also avoid pointy-toed shoes and choose a pair with more room in the toes instead.

If you’re trying to repair your feet and legs after years of wearing heels, try heel lifts (stand barefoot and repeatedly rise onto the balls of your feet) and heel drops (stand on the edge of a stair and slowly lower and raise your heels back to starting position).