I Slept and...Awoke

One day I awoke from a great nights rest and started thinking-wondering why in the world when most people go to sleep we do not die. How do we go to sleep and wake-night and morning?
I mentioned this to my sister. She looked at me with her brow raised and said," Uh...ok...um...interesting. Only you would think of that."
I thought this was a great miracle that God had created. He thought of every great detail for us live.
What do you think?
Have you ever thought why we do not die when we sleep?