A closer look
Gravity is the ultimate, free antacid if you know how to use it. Because of the asymmetrical shape of the human stomach, which naturally curves to the left side of your abdomen, sleeping on your left side keeps gastric juices pooled below the lower esophageal sphincter. If you roll over to your right side, that highly acidic liquid sits directly against the valve, significantly increasing the likelihood of it leaking into your esophagus and causing heartburn. Positioning is everything when your internal organs are poorly designed.
