On the Trello blog:
Can you be as effective in 35 hours as you are in 80? Startup veteran and developer Jess Martin thinks so. He has worked tirelessly to optimize his productivity in order to work better, not longer….
During his task driven days where he is heads down in code for hours, he makes a point of going to lunch with a friend “so that I’m actually having some human conversation.” Breaking up a heavily technical day with some socializing helps him to feel refreshed and keep going.