As someone who has worked hard for years (at some point I had three con-concurrent jobs), I’m not sure working hard is the variable that causes burnout :thinking_face:
I will say tho, it gave me persistent back problems and RSI for two years :). But that again is not just “working hard”. It was bad posture, lack of stretching, breaks and exercise, I think.
Edit: Perhaps it’s the nature of the work or working hard unhealthily (physical and mental?) or the person’s characteristics.