Friend of mine, for some reason sleeps alot, up maybe 30 to 40min. then back to sleep, drinks a lot of caffeine, but still don't work.?

Hibernation: First you have to realize that many of us are built to have a mild hibernation in the winter. In other words, we slow down, eat more, our sleep is a bit less deep but our awake periods are less alert. The problem is that modern life is not compatible with that. The best solution is to use light and dark strategically to strengthen our circadian (night and day) biorhythms.