Back when I was Shipping for a company, I loaded a truck (then drove it) and unloaded about 4.75 tons per day. No forklift...just a dolly...ugh. Each box (~45 lbs / 20.5 kg) had to be lifted and loaded into the truck (and then unloaded) one-by-one. I also averaged 15,000 steps per day. Wow, did I get fit!
I always sucked at using the shrinkwrap machine. Like comical level sucked.
That job would have eventually destroyed my body from wear.
Once I was doing accounting at the same company, I realized my body would not be destroyed by wear, but the combination of sitting and stress meant I would eventually stroke out and leave a well-preserved corpse.
Cheers,
Ian