This is where it gets fascinating. The stomach is naturally positioned on the left side of the body. When you sleep on your left side, the junction between the stomach and the esophagus remains above the level of the gastric fluids. Consequently, it is much more difficult for acids to travel back up.
Conversely, sleeping on your right side can facilitate this unwanted movement. It is not an absolute rule—every body is different—but several gastroenterology studies confirm this tendency. If you have always preferred sleeping on your right side, perhaps it is time to try the other!
Other habits that truly make a difference
Sleep position is one factor, but it is not the only one. Here is what doctors most often recommend:
Eat dinner earlier. Ideally, allow two to three hours between your last meal and the time you go to bed. Having a full stomach while lying down is a combination best avoided.