posted on Jul, 7 2009 @ 11:36 PM
Age. Boy was that an eye opener the first time I was completely dragging after pulling an all nighter.
It could also be stress or depression, both of which sap your energy and physiologically cause you to sleep more.
It could also be a change in activity level or schedule. When I first started working in the corporate world, I couldn't believe how tired I was at
the end of the day. After all, all I did was sit in front of a computer programming websites. Yet, the mind gets fatigued, too.
If you have a new schedule, the times where you're most active could be effecting the times where you used to be more alert.
Plus, if you don't have anything to do later at night, because friends have school or work that you'd usually hang out with or whatever, the
external motivations for alertness would be gone and your body might just be screaming, "Finally!"
So lots and lots of reasons