why do my dreams get more lucid the more I sleep?

[Gummage]

I had a real long night sat night and I slept for a full 11 hours today (Sunday) which is very unusual for me as I usually just am done with  8 or 9 hours sleep but I was feeling extra lazy. What I found interesting when I woke up was my dreams were more conscious/lucid than normal during my sleep and I think they seemed to happen at the later part of my sleeping and not the start or middle of my 11 hours. Does anyone know why this might be? is it common for people to have more lucid dreams the longer they sleep? if so then why?

I figured this could be useful if it happens again as I could use the low levels of consciousness to ask for "increased clarity" if I can and then if it works the consciousness can be heightened enough for a full blown OBE! what you guys think? but I mainly just wondered why this happens.

[Xanth]

It has something to do with your Sleep Cycles, specifically the REM portion of those cycles becoming shorter and shorter as the night progresses.

[Szaxx]

It's this exact thing that helps many learning the art to achieve success.
Your body has recharged so to speak and your concious self is handed back earlier. This can be used to your advantage. 80% of those learning the art have success at this time.