There are lots of "normal" jobs that destroy your body from the day to day abuse. I have seen mechanics with knees and backs destroyed due to the nature of their work. Carpet installers who are hunched over day in and day out for hours every day cant stand up straight also with knee and back issues. Hell even us desktop warriors have our own sort of physical aliments. Bad eyes, carpal tunnel, obesity. Draw the line however you want but there is nothing that is without risk.