The way you put your bed and your bedroom has a big influence on how good you sleep and thus on how much energy you have for the day.
The master bedroom should be in the south west or if not possible north west in the house. The best way to sleep is with your head to the south. Never sleep with your head to the north.
Childeren and students can have there bed east west sleeping head to the east. Sleeping with your head eastwards is said to be good for knowledge.
Place your bed in such a way that there is more space left in the bedroom to the north and to the east. For example putting your bed in the south west corner.
Make sure that you open the windows of your bedroom everyday for a while. Vastu says that by opening your windows fresh energy can enter the bedroom.
Sleeping is essential in our lifes, the more sound sleep we have the better we can perform. Energy flows over the earth from the north pole to the south.
Your body is magnetic. Your cells are magnetic. Meaning there are plus and minus poles in all your cells but also for your whole body.
Vastu says your head is the positive pole of your body. Just like with magnets they can click and hold each other or they "fight" eachother and push each other away. That is why you should never sleep facing north.
More information about magnetic fields can be found on Defenition of Polarity.