Could it because we are lack of iron? I heard that lack of iron can cause people feel fatigue.
By the way, today I found something called Sleep Tracker on the web. It is a watch that (it is said) can track your sleep order and will wake you up at the right time - when you are at the almost-awake stage so that you wake up refreshed and energetic. Has anybody tried it or heard of it? Do you think it works?
It is painful to have this sleep disorder. Early risers, I admire you.