You can indeed work permanent nights, and I did so at A&E for a year. Basically your body adjusts completely, so you end up sleeping the same amount of time as 'normal' people instead of the increased time you can find yourself sleeping on rotating shifts. It isn't as stressful on your body because you aren't constantly resetting your body clock, but... ...You can easily end up socially secluded internet and timezones not-withstanding. You need to take multivitamins because the body only makes some vitamins in the presence of daylight, and it can be a right git to do simple things like visit banks, keep appointments and other day to day stuff. However, some people do work permanent nights and enjoy it, I'm considering it myself when my current ghosting is up...