First of all, the first half of the sentence says "don't die lying down", which means that when you sleep, don't sleep on your back like a dead person. This is our sleeping position. In the eyes of the ancients, it was very unlucky to sleep directly in the sky like this, because it was like a dead man.
In fact, this sentence is not just superstition. From the point of view of modern medicine, if people sleep on their backs like this, it is easy for us to find a comfortable position for our hands, so it is easy to put our hands on our chest and abdomen. If we take this posture, our hearts will be oppressed, and we will easily snore and have nightmares when we sleep.
At the same time, sleeping on your back can easily make our saliva choke into the trachea, and even lead to suffocation during sleep in severe cases, so no matter what angle you are from, it is best not to adopt such a sleeping position.
Then let's talk about the second half of the sentence "Don't sleep north", which means don't sleep with your head facing north. Is this sentence reasonable?
In fact, there is this sentence, which is explained in ancient books in China. We say this because such sleeping habits are closely related to our living habits. Because China is located in the northern hemisphere, the south is warmer, so the south wind is warmer and the north wind is colder, so don't face north when sleeping, that is, avoid the shady side.
In autumn and winter, if our heads are affected by a lot of cold, it is easy to cause some diseases, so our heads do not face north, which is also for our own safety and health.