Accidental Pseudo-WILD?

I had a really weird thing happen two nights ago. After getting a combined 6 hours of sleep the previous two nights, I was exhausted and ended up going to bed sometime between 12:30 and 12:45. I read my bio textbook for a bit, turned out the light, and lay down, thinking half about dreams and half about everything I had to do the next day. I wasn't aware of any sort of transition, but it seemed I was suddenly aware that I was dreaming, although I was still laying in the same position in bed. A nostril RC confirmed my suspicion. After I got out of bed everything seemed unclear and black, and I almost lost it before I bent over and cemented myself into the dream. It got more vivid as it went on.

When I woke up, the clock showed 1:30am, so the whole thing had to have happened in somewhere around 45 minutes. I didn't think REM came that quickly. What exactly happened here?

I think if you have a lack of sleep the previous nights, your brain causes something called "REM-rebound". I think it's when there's just an increase in REM time.

Someone more knowledgable on this could shed some more light.

Yeah, that's exactly what happens. When people change their sleeping habits at all, your body will adjust. When sleeping polyphasically you enter REM within five minutes of laying down, wake up 20 minutes later, and you feel refreshed. You needed your REM cycles so your body immediately transitioned to REM.

Also, that's why naps are good for some people to obtain lucid dreams as well.

I think I read somewhere that the whole "REM coming only after hours of sleep" thing isn't true, and that you can still dream right when you go to sleep, but hey what do I know? Sean's "REM-rebound" thing sounds more reasonable. Although once I fell asleep in class and could have sworn that my teacher turned into a monkey until I jerked and noticed that I was actually asleep. slightly emberassing :P but if I can't dream unelss I'm in REM and I can only be in REM after hours of sleep then what other explinations are there?

Almost all of my WILDs have been like that, I think it's pretty common.