During my masters, my classmates and I were consistently pulling 100+ hour work weeks for 4 months at a time (especially towards the end of the semester when projects were due). Even though we enjoyed the material and pace of learning, it was not sustainable. To cope, I sacrificed my gym time, stopped cooking and ate 16" subs that would last me through the night. As you can imagine, this combination led to a bad lifestyle plagued with weight gain and added stress.
I may sound insane, but it was an incredible experience. When I look back, I no longer remember the pain of those sleepless nights and instead I'm amazed by how much I learned in such a small period of time.
Currently I'm on a leave of absence to pursue my ideas, and I've found it difficult adjusting to the lack of structure in my daily routine (no classes, no assignments or projects due). I would like to maintain the intensity of my masters, while maintaining a healthy lifestyle. Based on the structure below, I believe an 84 hour work week is the sweet spot.
8 hours for sleep
A good sleep has many benefits such as better focus and improved health. Though studies have shown we are more creative when miserable.
12 hours for work
Set goals and commit. The objective is not to work aimlessly. Spend time to thoroughly think about the goals.
Focus and eliminate distractions. I recently worked from an all purpose room that was not equipped with wifi and my productivity went through the roof. Of course some tasks require you to be plugged in.
1 hour for gym
Exercise is a must to maintain sanity, and live a long life. All the success in the world will not make a difference if we aren't healthy to enjoy it.
2 hours are lost
We still need to shower, eat, run errands, and commute to places.
It is important to maintain relationships with family and close friends. Especially your parents who've been with you before you even knew how to crawl. Most of the times a thoughtful phone call is all it takes.
I don't have a wife or kids, but if I did they deserve more than just half an hour a day.
Unwind a little before heading to bed. Read a book, catch up on HN or watch the last period of a hockey game.
To be successful I believe one must pay their dues. According to the book Outliers, written by Malcolm Gladwell, it takes 10,000 hours of practice to become an expert in a domain. At 84 hour work weeks that would require 2.28 years as opposed to 4.79 years for those who abide by a 40 hour work week. Don't even get me started on those who live by the 4 hour work week.
If you suffer from burn out it never hurts to take a break. After a few days you'll be anxious to return and crush an 84 hour work week.