The stomach sits below the diaphragm, curving toward the left upper abdomen.
When you lie on your left side:
The junction between your esophagus and stomach (the lower esophageal sphincter) stays above the level of stomach contents
This makes it harder for acid to splash upward
In contrast, lying on the right side:
Positions the stomach higher than the esophagus
Creates a slope that encourages acid to flow back up
🔬 A 2005 study published in The American Journal of Gastroenterology found:
Participants experienced significantly less acid exposure during sleep when lying on the left side vs. the right.
💡 For many patients, this simple switch reduces nighttime heartburn — without medication.
2. Supports Natural Stomach Anatomy
The shape of the stomach follows a J-curve, with the top (fundus) on the left.
Sleeping on the left side:
