Why do I sleep so much?

[Ippo]

Hi, I noticed something strange in my sleep. If I use an alarm to wake me up after, say, 8 hours, I'm perfectly fine. I need some time to become fully functional, but during the day I feel ok. But, if I don't put an alarm clock, I sleep 10 hours AT LEAST, and once even 11 and a half. When I wake up after sleeping so much I feel much more tired than before, I've got headaches, and I'm generally nervous. How can that be? I mean, if 8 hours seems to be the perfect time for me, why can't I just wake up by myself and keep sleeping?

[nautilus]

How tired you are when you wake up depends a lot on which phase of sleep you wake up from. The average sleep cycle lasts between 90 and 110 minutes, so basically it's a bit variable. Maybe your body is adapted to fitting several sleep cycles into 8 hours such that you wake up out of a phase of sleep that doesn't make you feel groggy. At the same time, you don't always wake up after each sleep cycle (although I think I've heard of people learning to do just that). I do know that if you set your alarm and wake up at the same time every day (yes, even on weekends ), your body will eventually get used to it and you'll even wake up a bit before it goes off. If you get to that point, you'll probably be pretty alert during the day

[Zephyrus]

i have heard that having 7-8 hours of sleep is perfect, too much or too little is bad for you. Im not sure where the studies or the reasons why this are

[Ippo]

Yeah I've always been a night owl... In fact I started monitoring my sleeping time this week, trying to 1) wake up earlier (or at least at a human time) 2) stabilize my waking time. I'll let you know if that makes any difference. Unrelated question which I should probably open another topic for: is there any good book about sleep? I'm talking about something medical, not just essays by some writer, I'd like something a neurologist would consider good.