The Most Common Sleep Position: Side Sleeping
People generally sleep in three positions—side, back, and stomach positions. According to a 2017 study in Nature and Science of Sleep, side sleeping is the most popular, with 54 percent choosing that position,
Side sleeping includes three subtypes: fetal position, log, and yearner, says Duncan.
“In the log position, sleepers generally sleep on their side, with their arms and legs straight, while the fetal position (which is the most common side sleeping position), has the hips and knees bent,” he says. “Unlike the log and fetal positions, the yearner sleeping position consists of sleeping on the side, with the arms and legs outstretched in front.”
Side-sleeping helps ease pressure on the spine and helps to reduce acid reflux symptoms.
Duncan suggests that side-sleeping, with proper support between your knees and under your head, creates neutral hip and neck alignment. Also, sleeping on your left side places the stomach and its gastric juices lower than the esophagus. This helps prevent acid reflux, Duncan said.
However, side sleeping does have some downsides, including potentially harmful impact on the hips and shoulders.