How do you know if you are getting into Stage 4 sleep?? We all know about that morning "crash" feeling to some degree. I have it too and from what I hear if you don't get the right sleep it can have a lot to do with this horrible feeling. So, how do you know if you getting into stage 4 sleep? Do you have to employ a sleep therapist to figure this out? If you sleep straight through for a certan time period without waking, can this mean you were in stage 4 at some point? (For example, 4-5 hours straight). I am lucky to only wake up 1-3 times per night as compared to many others who wake much more often. any help is appreciated.