I did 80's (over 5 days) for an extended period of time twice and you definitely adjust. Looking back, the quality of work was definitely diminished. It didn't

I did 80's (over 5 days) for an extended period of time twice and you definitely adjust. Looking back, the quality of work was definitely diminished. It didn't impact me too greatly in the first because it was a sales role primarily filling out RFPs. The second time was my startup and I am confident I made plenty of bad decisions due to lack of relaxation/sleep/exercise.