Perhaps coincidentally, but I can rarely sleep more then 6 hours in a night. It seems that I've always been that way. My eyes just open after about 6 hours, and I feel the need to get out of bed. The only way I've ever been able to get more is when I'm hungover or ill.

I don't ever feel like I need to sleep more, but the anxiety I get from all the sleep studies telling me I do need to sleep more, sure does keep me up at night!