at a submarine watchfloor (the 'shore side' of submarine communications) we had a wild schedule: 5am to 5pm for two days, then 5pm to 5am for the next two days. Four days off after that, but then the cycle continues. I can't count the number of times I woke up several hundred yards from where I last was conscious - freeways, intersections, etc. Most of my coworkers had this issue as well. we finally convinced the command to go to a more normal policy, but this took decades.