Stamina for Work

I've been thinking about stamina today because in the world of writing and grading, one needs a certain ability to keep at it for long periods of time.

Imagine grading a stack of 50 five-page essays, for example (and some faculty I know teach twice my load and have 100 five-page essays) that you want to return to students by the end of the week. Imagine working on a 40,000 word manuscript that's due in a month. Imagine your own work project that you're currently tackling that requires a long mental commitment for a long period of time. 

What helps grow stamina? I'm not an expert, but here are some tricks I've learned from myself and from professional friends for an 8-hour work day. Here's what I've learned:

• Every hour, take a 15 minute break to do something else that doesn't involve the same kind of mental work. 
• Every three hours, walk away from the project for 30 minutes to relax completely (bath, walk, reading, television, lunch with friends, etc). 
• Have delicious snacks to munch that don't involve sugar, or you will crash later. 
• Only drink two cups of coffee, or you will crash later. Drink water after that. 
• Put a reward system in place during your most mentally fatigued time. Perhaps if you complete an hour of work, you can reward yourself with some kind of prize. In other words, motivate yourself somehow and prepare your environment for a mental boost with prizes or treats like new music and novel snacks.
• At your half-way point of the day, stop and do jumping jacks or dance. Anything to move for a few minutes. Sedentary work, I'm learning, isn't good for energy levels. 
• After you've put in your work hours, totally walk away and disengage from it. Don't go back to the computer at all. 
• Eat a great dinner and get 8 hours of sleep, begin the next day with prayer and exercise, and then start the whole process over again. 

What would you add to the list?