If you habitually sleep exclusively on your right side, you might want to consider how that position interacts with your digestion, particularly if you are prone to nighttime heartburn or acid reflux.
Anatomically, the stomach sits on the left side of the upper abdomen, and the lower esophageal sphincter (the muscular valve that keeps stomach contents from rising) rests below the level of gastric acid when you lie on your right. Sleeping on your right side can cause that valve to relax or sit lower than the pool of stomach acid, making it much easier for acid to wash back up into the esophagus and trigger reflux symptoms.
Conversely, sleeping on your left side keeps the gastric junction positioned above the level of stomach acid, utilizing gravity to help keep everything where it belongs.
While side-sleeping preferences are hard to break and right-side sleeping isn’t inherently dangerous for healthy individuals, making a conscious effort to transition to your left side—or elevating the head of your bed slightly—can offer noticeable relief if you ever wake up with a burning throat or sour taste.
