Heavy, Deep or Dead Sleep?
I am wondering which adjective is better to describe sleeping well;
1) heavy sleep
2) deep sleep
3) dead sleep
My dictionay gives me above three expressions, but an internet site uses "heavy sleep" to describe "sleeping excessively of sleeping disorders", and "dead sleep" give me an image of "eternal rest of person who has passed away." Is "deep sleep" better expression?
Moreover, I would appreciate it if you tell me some atonyms of it.
Thank you for reading my question.