I still do the same thing, 36 hours shifts are good to get the job done (+/- 24 up and 12 sleeping). Fortunately, my job is open to such horary and i can keep it for now. When i try to get "normal" sleeping rates (16h up/8h sleeping, as my girl friend says "normal"), i mess up the whole day, and really looks like a tired guy. Dunno why, but 36h shifts are good to me.