RELATED: If You Do This When You Sleep, Talk to Your Doctor, Study Says. While research on the topic is still lacking, some scientists have explored how sleeping in different positions could potentially affect your heart, Healthline reports. One such study conducted in 1997 tested 40 subjects—18 of whom had been diagnosed with heart disease and 22 considered healthy—using an electrocardiogram (ECG) to monitor electrical activity in the heart while they switched between sleeping on their back and sides. Results showed that participants sleeping on their left side saw the most significant changes to their ECG ratings while resting.

A separate study conducted in 2018 also used ECG to monitor the heart data from 9 subjects. Similar to the 1997 study, results also found that participants sleeping on their left sides had significant changes in their heart’s electrical activity. But in this study, an imaging technique known as vectorcardiography also showed that the heart turned and shifted while in that position, which researchers said may explain the recorded changes. In comparison, almost no ECG changes were recorded while participants slept on their right side, Healthline reports. Imaging showed a thin layer of tissue between the lungs known as the mediastinum actually held the heart securely in place while sleeping that way. However, both studies quickly concluded that more research would be needed on how sleep position could affect the heart’s activity overall. And while some patients who have been diagnosed with congestive heart failure have reported trouble breathing or discomfort while sleeping on their left side, there is no conclusive evidence that sleeping on your left side could be putting you at an increased risk of heart disease if you don’t already have a condition.

RELATED: For more up-to-date information, sign up for our daily newsletter. On the other hand, some experts claim that sleeping on your left side is not harmful but can actually help its function. According to W. Christopher Winter, MD, medical director of the Martha Jefferson Hospital Sleep Medicine Center in Charlottesville, Virginia, it has to do with how blood circulates. Since blood reenters the heart through the right atrium on the right side of the body, sleeping on your right side could cause pressure on the major blood vessels that feed the organ. However, “sleeping on your left side with your right side not squished is supposed to potentially increase blood flow back to your heart,” Winter told CNN in a 2016 interview. Of course, advice on sleeping positions is different for those who have already been diagnosed with heart disease. And while all recommendations should come from your physician in these cases, some doctors support the idea that avoiding their left side at night could be beneficial.ae0fcc31ae342fd3a1346ebb1f342fcb “Those who have had heart failure or other heart conditions should sleep on their right side whenever possible. Right-side sleeping lets the heart rest in place with help from the mediastinum, preventing the disruption of your heart’s electrical current,” Tri-City Cardiology in Mesa, Arizona writes, echoing the findings of the previous studies. “This will help ward off breathing issues and discomfort while sleeping.” However, they warn that rolling over onto your back can create another problem, saying that the position “can worsen sleep apnea, and people with sleep apnea are more likely to experience heart disease.” Instead of creating back pain by lying on your stomach, the experts recommend sleeping on your back and elevating your head with pillows, which helps promote easier breathing and reduces the pressure on your heart. RELATED: If You Notice This While Lying on Your Back, Get Your Heart Checked.