When I was reading about Feng Shui, I learnt that to have the foot of the bed directly in line with the door is bad - it makes you easier to carry out in a direct line when stiff.
There is some substance in the notion that to sleep in alignment with magnetic poles is beneficial. We all have our own magnetic field around us and it seems reasonable to align it with that of the Earth.
Unfortunately many modern homes don't provide enough bedroom space to comply.