Quote from Ariesbsn
I think it depends on a person's circadian rhythm. I have been a "night person" since I was an infant (according to my mother). My brain doesn't engage until noon and I perk up at 2200. I also sleep better during the day. I am diabetic and don't have a problem controlling my blood sugar on nights, as long as I watch what I eat.
Day shift is a completely different story. It doesn't matter if I do 8 hour shifts or 12 hour shifts, if I am on days, I am asleep with 30 minutes of getting home when I work day shift. When I get home from a 12 hour night shift, it usually takes me 3 hours to wind down enough to be able to sleep.
I remember reading all the scare stories. But then I read a wonderful article (wish I'd saved it) that said the hazards don't apply to those who work nights voluntarily.
People who work third shift against their will
have higher stress levels and all sorts of other fallout from fighting their innate circadian rhythms. But for those of us who do it by choice because it does line up with our bio-clocks, there appears to be little or no increase in health problems.
I personally would hate, hate, hate to work days. The few times I have had to do it for orientation purposes darn near finished me off. At least it gave me empathy for what nights feels like to others. I am naturally a night owl. When I'm not working, I sleep from 0400 to 1200. Working nights comes naturally to me.
So, it's not so much the hours as how your bio-clock responds to them. I'm not certain whether you can train yourself to have different circadian rhythms. All I know is that I have always been able to find a job because I can do third shift.