Does it have to be exactly 4 hours after you wake up? I woke up at 7 today, ate lunch at 11 and went to bed about half an hour after that. I was in that state where I'm really relaxed and I have those random "dream flashes" but then I got a text and I can't go back. Is there a set period of time after you wake up that your REM is strongest and then it just goes away?