Q. Is it better for digestion to sleep on the left side and better for the heart to sleep on the right?

A. There is some evidence that sleeping position may be related to heart function, though it may be more a matter of an existing heart problem’s resulting in avoidance of sleeping on the left. As for digestion, at least one study found that gastroesophageal reflux can be somewhat increased when sleeping on the right side.

In a 2003 study published in The Journal of the American College of Cardiology, subjects with congestive heart failure had a “highly significant tendency to avoid sleeping on the left side,” while subjects without the condition did not. The study’s authors also found that avoidance of sleeping on the left was related to the degree of heart enlargement and dysfunction.

The findings were in keeping with the concept that a left-hand position “may exert deleterious effects” on heart pressure, cardiac output or the functioning of cardiac nerves and thus “may be a protective strategy,” researchers said, adding that the position choice might arise from discomfort from perceiving a stronger heartbeat.

A study of digestive reflux published in 1994 in The Journal of Clinical Gastroenterology found that the total amount of reflux time was significantly greater when sleeping on the right, though the number of episodes was not significantly greater.