So I have this friend, who is in the Navy. He wants me to ask on this forum what people's opinions are on the best method of structuring sleep while on deployment.

The ship keeps an 8 hour rotation system, where you work for 8 hours, and then have 8 hours off, and then 8 hours work, and 8 hours off, and so on and so on. This continues for the length of the deployment (several months sometimes).

During the 8 hours off, you are expected to structure your leisure time, sleep, and exercise as you see fit. Meal times are not flexible however, with meals being served during the normal parts of the day, plus an extra dinner at midnight for people coming off shift work.

What system of sleep - exercise - and work would be the least destructive, also allowing for adequate fitness training to at least maintain body weight exercises like pushups, chinups, squats etc etc (very small space to work with - kind of like prison workouts).

He was thinking something like:

8 hours work
1 hour eat / recreation / relax
5 hours sleep
2 hours eat / exercise then back into;
8 hours work again

(possibly every 2-3 rotations doing nothing but sleeping and eating on the 8 hours off).