3. Heart Health
Gravity can also help your heart work more efficiently. Residing on the left side of your chest, the heart more easily drains lymph when you lie that way. Your aorta, the biggest artery in the entire body, also arches to the left as it leaves the heart and heads down toward the abdomen. Left-sided sleeping means that blood leaving the heart is assisted by gravity and requires less pumping action by the heart itself.
When you sleep on the left, pressure on the inferior vena cava (which brings blood back toward the heart) is also relieved as your intestines hang away from it. Overall, blood circulation can be improved with this position, simply by relieving a little pressure.