HA! And just for emphasis, HA!!!
Lack of sleep was my biggest issue when I was in the Navy (in submarines).
I went for four months once without getting more than 3 hours of sleep in a row. Once, I got less than 12 hours of sleep in a whole week.
On a submarine, you have three watch rotations who stand rotating shifts. A typical rotation goes as follows:
0000-0600: SLEEP
0600-1200: Watch (e.g. in the Control Room, Engineroom, etc.)
1300-1700: All-hands drills
1800-2400: Admin duties
0000-0600: Watch
0600-1200: Mandatory training
1300-1700: All-hands drills
1800-2400: Watch
0000-0600: SLEEP
0600-1200: Training
1200-1800: Watch (drills in the middle)
1800-2400: Admin duties
This is the best possible case for a 3-section watch rotation, and you only get two nights of sleep every three days. Also, during your time off-watch, you have to work on your qualifications, including standing under-instruction watches.
Now stir up the mix. We went to extended “Section Tracking Party” (a modified Battle Stations) when doing super-secret spy shit for months on end. Each off-going EOOW (Engineering Officer of the Watch) stood a full watch in the control room after their watch back in engineering. We were therefore standing watch for 12 hours on, 6 hours off. During that 6 hours, we assisted with track reconstruction. This only left about 2-3 hours every 18 for any possibility of sleep.
We also went to actual Battle Stations numerous times, when everyone on the ship was up. We stood Battle Stations for 12-14 hours at times. When the Battle Stations was secured, if you had the watch, you stood it, even if it meant you would be up all night.
You can damn well bet it affected my health. :mad:
But I’m not bitter or anything. 
P.S. They mentioned during the show how much the sailors were making, if you added up all the hours they actually worked. I recall once figuring out (on watch) that, even though I was an officer, I was making much less than minimum wage. :dubious: