Exhaustion leads to serious problems and, in the airline industry, that often leads to disasters (https://en.wikipedia.org/wiki/Colgan_Air_Flight_3407). Hence the legislation for limiting the number of hours a pilot can fly in a month. There's a lot of science behind that decision - for good reason. It's a mature approach to managing the human resource (pilots) that seems to be absent in other industries. I really wish there were more studies regarding the level of concentration needed to solve software problems and how long that level of concentration can be maintained (weeks? months?) before exhaustion sets in - swiftly followed by burnout.