Since nobody has meantioned a "breathing technique" yet, when my mind starts turning to mush and everything starts looking like 1s and 0s - I practice the Ibuki (similar to Chinese Qiqong) breathing techniques of Goju-ryu Karatedo. This mainly means Sanchin training but I've found the breathing and movements of Tai Chi and other "soft" styles of kung-fu and even Yoga to help in regaining alot of energy as well.