Decoding sleeping positions: The best mattress types for side, back, and stomach sleepers | The Canberra Times

Stomach sleeping is the rarest position and the most physiologically problematic. When you lie face down, gravity targets your torso and hips predominantly. If your mattress has some gentle sinking, your hips will drop below the rest of your body, forcing your lower spine into an overly extended, unnatural arch. Over time, this leads to chronic, debilitating lower back pain.