Being exposed to the elements and, I'm assuming in decent shape based off what you said, is pretty different from being indoors sitting all day on a likely less ideal diet.

Also how much you smell depends on how hairy you are too.

I've gone camping and without long showers too due to lack of water out in the wilderness, even going nearly barefoot, but between the dirt dust and nature's VOCs sticking on you, it's hard to smell too bad unless you're sweating like crazy as you do some kind of manual labor. And even then, the sun is a good deodorant.

Same with sailing - I think the salt spray inhibits things.

The other thing I don't wear underwear when out camping. So there's much more air down there too. Not the case if using underwear and sitting in a chair all day.