knackered

2003, Hugh Dauncey, Geoff Hare (editors), The Tour de France, 1903-2003: A Century of Sporting Structures, Meanings and Values, Frank Cass Publishers, London, 2005, page 225, Then, it all just gets worse and worse, you don't sleep so much, so you don't recover as well from the day's racing, so you go into your reserves, you get more knackered, so you sleep less... It's simply a vicious circle.