Meaning, you can somewhat opt out of the damage sedentary labor does to the body by exercising and using your body. It is much more difficult to avoid manual labor from damaging the body.
Sure, which is why many white collar workers look down on tradesmen (in the US at least), and tradesmen look down on white collar workers as "bullshit email jobs".
Huh? It's not clear to me what you're trying to say here.