Why we sleep for long hours sometimes?

i think tiredness is main reason...for long hours of sleeping...

Also when we get to get a opportunity to have a stress free sleep we tend to sleep more.

We sleep sometimes for longer hours because we need more sleep to cover less sleep last night or tiredness or the room environment provokes more sleep. Some times, when you get up early but again fall asleep, the total duration of sleep will be more.

usually its abt 6-7 hours...when exams are around the corner it becomes more like 2-3 hours or even less...during vacations i sit up entire nights in front of my pc,be it internet or watching movies.

I think we sleep for more hours sometimes due to stress and stain.... The body when needs rest would make us sleep for some hours to become active again!!!!

More often, longer sleep only means that we are covering up for less sleep in the previous days, usually people who get up very early during the weekdays will sleep late on the weekly off days! This is quite normal for working people! but if you start sleeping for longer periods very often and still feel tired and exhausted, then there is cause for concern. It usually means onset of some illness or even most commonly when you are mentally depressed!

It is symptoms of some health problems or people who are aneamic.Other than that strain is another reason..If it happens frequently visiting doctor is good