80.5 hours in 4 days is a ridiculous amount, considering there are only 24 hours in a day and you need to spend some of that time sleeping. According to this, you only got an average of 3-4 hours per night, and that's if you spent every spare moment from work sleeping!

The body and mind need adequate rest to recover and recharge. Without that you will be doing a sub-optimal job at best. What kind of work are you in that requires such insane hours? Can you ask to work less?