This is a big reason why unions were created in the first place. Create safer working conditions, and make it possible for people who wear their bodies out can retire.
But what if I want to retire with a healthy body not a crippled one?
Then you choose not to perform manual labor. In an ideal situation, the market will pay people a premium for choosing to sacrifice their bodies, assuming everyone is competing on a level playing field and you don't have a huge supply of undereducated workers from another country who have no other options.