cardiovascular interval training can have a profound effect on your ability to quickly release tension and recover from mental exhaustion. What is more, physical flushing and mental clarity are very much intertwined. There was more than one occasion that I got up from the board four or five hours into a hugely tense chess game, walked outside the playing hall, and sprinted fifty yards or up six flights of stairs. Then I’d walk back, wash my face, and be completely renewed.
