Three interesting paragraphs from Paul Hoffman's new book King's Gambit: A Son, a Father, and the World's Most Dangerous Game
When a player gets violent, his wrath is often directed not at spectators or his opponent but at himself. One contemporary Russian grandmaster has been known to pick up the pointiest chess piece, usually the bishop or a knight with a particularly jagged mane, and stab his own head until it bleeds. Then he rushes out of the tournament hall only to return for the next round as if nothing untoward has happened. At one event, this grandmaster was among the tournament leaders who were playing on an elevated stage. When he lost a key game, he bloodied his face and then, in an extreme masochistic flourish, dove off the three-foot-high stage, belly-flopping onto the hard floor.
Such behavior is exceptional, but even stable personalities have trouble accepting defeat. Garry Kasparov, the thirteenth world champion, frequently storms off like a bull, shoving aside spectators who are in his path. Pascal can be withdrawn and sullen for hours. When I lose, I repeatedly remind myself that chess is only a game. Yet even that reminder doesn't stop me from replaying in my head not only the moves of the game where I went astray, but also all the other things in my life that have gone wrong.
Most of the world's top players have strenuous exercise routines to balance their sedentary chess playing. Bobby Fischer worked out regularly long before it was fashionable, and Kasparov pumped iron, swam, and rowed as part of his chess training. "Your body has to be in top condition," Fischer said. "Your chess deteriorates as your body does. You can't separate mind from body."