How to maximize work productivity with optimized working hours

No.

I thought it came from the monks who worked 8 hours, prayed 8 hours and slept 8 hours

I'm currently implementing the "work for five minutes, make coffee for an hour, then browse the Internet for the next 6 hours and 55 minutes" approach.

How about the "spend thirty minutes on the shitter" approach?

Tl;dr