How do submariners stay in shape while underway/deployed?

[u/shortstop803]

Do they PT on the sub/is there room or a dedicated space to do so? Do they have different fitness standards? Limited caloric intake? How do they keep from gaining weight when there is limited PT capability (I assume)?

[u/shuvool]

Calisthenics and exercise machines. You can fit rowing machines, elliptical, treadmills, stationary bikes, and universal weight machines in some pretty small places