For about three months every year, for work (wildlife surveys) I wake up around 4 am, sometimes a bit earlier or later, and usually have a short but steep hike to where I'll actually be performing the work. The survey lasts two hours, I then hike back, nap for 30-90 minutes, then do the daytime part of my job (more hiking, visiting areas and figuring out specific spots to survey in the future, cutting trails through brush that I can follow in the dark). If I don't have the nap, I feel noticeably more tired. After 5 days of this, I feel very sleep deprived and out of it. I am always in bed by 9 pm, I'm not a great sleeper but I've figured out how to maximize my chances. The physical aspect of the job isn't actually that demanding, I consider these three months to be the easiest, physically speaking, out of my year. There are plenty of other people who wake up early and work harder than I do, are you all exhausted all the time? I've noticed that when I'm on a similar schedule for hunting (without the nap), I don't feel as tired, or the same kind of sleep-dep tired. If you wake up early and perform physically demanding work, are you feeling sleep deprived and if you do how do you manage it?