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?

Question

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?

In: Biology

Answer 1

If you physically exerted yourself to the point of exhaustion at the gym for 8 hours a day for 20+ years doing only a few exercises, that would cause permanent damage too.