early risers

Why is it that my kids are such early risers? No matter what time they go to bed they are up at the crack of dawn. And they can't just come out and watch t.v. no that would be to easy. They are up, loud, running around, playing with their toys. I tell them quiet time is until 7:00. They dont listen. And they have their energy all day. Never slow down. I wish I had all their energy.