I'd put my physical rural lifestyle up there as a net positive, though. It's like cross-training. At least through 52 years.... knock on wood. Was in a customer's shop the other day and they had a calibrated scale. At pushing 6'-4", fully clothed, wallet & keys and phone etc, 203 lbs. So, under 200, which ain't bad at all.
Where I know for certain you are correct is in the muscle groups that get out of balance if you are just "working", like the abs. My back is strong like ox. My abs, not so much.
But to your point, carrying full sheets of OSB up a ladder onto a roof is dangerous. Period. But it's a heck of a workout! And tree work?! Shudder. Those guys are nuts. It's dangerous enough cutting trees down, I do that all the time........ from the GROUND!
At the end of the day I'm just frugal and enjoy working outside with my body. Dunno how much it'd cost to pay others to do this.... $1500? Screw THAT. I can fix it for ~$150. The rest goes in the boat fund.
And tree work?! Shudder. Those guys are nuts. It's dangerous enough cutting trees down, I do that all the time........ from the GROUND! 
