Does anyone have any info on sleep patterns? More specifically, I'm trying to figure out how long each stage of sleep typically lasts. Really, I'm just looking for some kind of explanation as to why, every night for the last week, I've woken up almost exactly 4 hours after falling asleep. I'd say stress or nightmares or apnea or something if it weren't for the incredible regularity of it. And I'd say environmental, but as my bedtime varies, this phenomenon follows suit. If I go to sleep at 11, I wake up at 3. Last night after the 6OT 'Cuse/UConn game, I went to sleep at 2 am and woke up at 6. So I'm attempting to figure out what's going on in sleepyland 4 hours after I've arrived there, and why I keep getting kicked out. Any ideas?