How is sleeping lying down more healthy?

Sleeping on left side is more healthy.

Blood enters our heart from the right side. Therefore, if you sleep on your right side, the veins of the right blood flow are obstructed by the pressure of the body weight.
Many people sleep on their right side and get heartburn. The main reason for this is that if we sleep on our right side after eating fried food, the acid level of our esophagus increases, so it is easier for the acids to be released in this condition.

Pregnant women are advised to sleep on their left side so as not to put pressure on the uterus with their liver.

And those who suffer from spine or back pain are told to sleep straight on their backs in which our spine stays in a normal position.

Taking a high pillow in this condition creates pressure on the neck. But it is better to take a little thin pillow because the acids of the esophagus cannot come up in it.

But the worst position is sleeping on stomach. Sleeping like this puts pressure on our whole body starting from the chest. And if we sleep like this, there is no breathing by turning the head to the right or left, for which there is a lot of pressure on the neck bones.

So we understand that the pillow or sleeping position is different for everyone. But everyone will request not to sleep on stomach. If your chest is burning, sleep on your left side and put a pillow down so that your neck is parallel. If your back hurts, sleep on your back with a thin pillow.

Sources:
https://www.healthline.com/health/sleeping-without-a-pillow

https://www.medicalnewstoday.com/articles/sleeping-without-a-pillow