What you might not realize is that the position that you sleep in could be preventing you from possessing that youthful glow of your dreams. Although it’s termed “beauty sleep” because your skin goes into repair mode, lying in a certain position for several hours a night could be compromising your complexion. Why? According to Konstantin Vasyukevich, MD, a cosmetic doctor and board-certified facial plastic surgeon in New York City, the horizontal position your body takes during sleep shifts the balance of fluid distribution towards the upper body (which is why facial swelling is usually seen early in the morning). “The long-term effects of this continuous cyclical swelling should not be underestimated,” says Dr. Vasyukevich. “Daily expansion and contraction of the facial tissue put a strain on the ligamentous support of the face. This eventually leads to stretching and sagging associated with an aged appearance.” Sure, most of us wrangle and contort ourselves into all sorts of odd poses at nighttime, but everything boils down to three primary positions. We consulted Dr. Vasyukevich about them to find out which one is best—and which is responsible for creating those premature sleep wrinkles. RELATED: 8 Ways to Revive Tired Skin After a Bad Night’s Sleep