People need not worry about north and south and whether they should sleep one way or the other.

The north-south concern typically reflects the crackpot theories of Robert Fludd (1574-1637), the founder of English Rosicrucianism, who believed there were two principles to all things: condensation (the boreal or northern virtue) and rarefaction (the southern or austral virtue).

Fludd had similarly peculiar ideas about magnetism. He believed that humans had north and south poles like the Earth, and magnetism could only take place when humans slept in a boreal position. That was supposed to be enough to remove the harmful effects of the demons that Fludd believed were inhabiting the human body and causing all illnesses.

When you learn more it looks even sillier.