I think the issue of productivity extremely depends on the person.
For me: I like to work 4 14hr days with a 2 hour gym break in the middle. Not 4 days in a row either.
This works for me because the gym really breaks up my work day and I am most efficient when I get "in the zone". Also, when I am in the zone, I hate being interrupted or leaving work. It takes 2-3 hours for me to get into the zone some times though.
I am 24 years old, the lead engineer at my company, amateur personal trainer, and power lifter.
For me: I like to work 4 14hr days with a 2 hour gym break in the middle. Not 4 days in a row either.
This works for me because the gym really breaks up my work day and I am most efficient when I get "in the zone". Also, when I am in the zone, I hate being interrupted or leaving work. It takes 2-3 hours for me to get into the zone some times though.
I am 24 years old, the lead engineer at my company, amateur personal trainer, and power lifter.