Starship pilot who has a workout regimen that would make any space marine blush
See, the thing nobody warns you about on a starship is the gravity, or rather, the lack thereof. Everyone assumes that because we know how to generate artificial gravity means that we do it everywhere. Problem is, the generators are big, expensive, and inefficient. Even on stations, only a small portion of it actually has gravity, and even less on a ship. It's only really a concern if you're transporting living cargo or passengers. Basically everything else you can just strap down so it doesn't float away and you're good. Even then, it's probably only the passenger bays that have gravity. Any ship that doesn't move live goods doesn't bother with grav. Yes, even the navy. Especially the navy.
So, you're stuck in micrograv at best for years at a time, and as a result your body starts to pull itself apart very slowly until you can't actually do anything. There's basically nothing you can do to stop this if you're stuck doing this for a living, but you can at least slow it down with exercise. Lots, and lots, and lots of exercise. Minimum three hours every day, mostly intensive strength training and cardio. Again, that's not building muscle, that's reducing atrophy. Everybody gets off a spaceship skinnier than they were when they got on, there's no getting around it. Hell, I've heard some folks can't even go back planetside after doing this long enough, too much stress on the joints and organs after decades in zero-g.
But sure, tell me how rough basic was.