Why do I feel dizzy when I just get out of bed?

Why do I feel dizzy when I just get out of bed?

When a person who was lying down suddenly stands up, there may be a lowered supply of blood to the brain for a short time, until the heart can get to beating harder.

The body needs a whole lot of automatic controls to allow us to do so many different things. It's amazing that they work so well that we do not feel dizzy more often than we do.