It obviously depends on the person and their approach. Nobody is confused why elite athletes can run faster/longer but there is a lot of debate about "work-life balance". Being a "workaholic" is similar to being an elite athlete if done right, and for most people it requires lots of ramp up time to being able to work longer hours as well as proper "conditioning" such as diet/exercise consideration, as well as a genetic predisposition and explicit effort toward maintaining psych.