I try to shoot for the token 8 hours each night, however, I have found that lately I have been sleeping from about 6 or 7 hours then waking up. At this point I feel pretty refreshed, however, I am able to go back to sleep a little while after this. For example, this morning, I woke up at 6:45 and laid back down, re awaking upon 8:30. At this point, I am completely tired , and have to drag myself out of bed. My question is, is it better to sleep the straight 7 and get up, or sleep the 7 then go back to sleep for the sake of additional hours. Although I want to get as much sleep as possible, I sometimes wonder if it hurts the rythm to go back to sleep after awaking refreshed.