Whenever I nap, I awake with my heart beating fast. It has been that way for as long as I can remember. Your body does go through things as you are waking up, but there also could be any number of things like a bad dream or something like over exercising or weight training even
There are a number of things that can do this. If you don't mind I have a few questions.
1. When you wake up, are you NOTICING things? Sorry, what I mean, is when you wake up, are you paying MORE attention to things than people usually would?
2. How much caffeine do you drink/eat every day?
3. Do you eat a lot of chocolate?
4. Do you have allergies?
5. Do you live somewhere that loud noises randomly go off?