system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is physically exerting yourself to the point of exhaustion at the gym good for you but various jobs involving manual labor seem to cause permanent damage in the long term?
gpt
Exercise is a controlled form of stress on the musculoskeletal and cardiovascular systems when done correctly. This, plus appropriate recovery time and nutrition, allows the body to strengthen itself over time via natural repair/adaptation mechanisms. Manual labor is not necessarily so controlled, and demands on the body may exceed its ability to adapt when repeated without appropriate recovery time -- which is not atypical for many of these jobs. Add workplace injuries into the mix and you can do quite a bit of damage over a career, whereas a reasonable exercise regimen under controlled circumstances should have a net positive result for strength, endurance, etc.