Years ago, when I managed a printing/publishing company, we had a major printing job that took three days straight, round the clock. The printing staff worked 12 hour shifts but I did a thirty six hour startup shift, went home to generally pass out for 8 hours and went back for another two 12 hour shifts. Almost all of it was hands on, not just supervision. That was in the 80's and I am not sure I have recovered yet.