Norwegian swimmer Alexander Dale Oen dies aged 26 © Reuters/Laszlo Balogh Norwegian swimming world champion Alexander Dale Oen has died of a cardiac arrest at the age of 26. Dale Oen had been attending an altitude training camp in Arizona. The swimmer took an emotional men's 100 metres breaststroke gold medal at last year's world championships in Shanghai and was a silver medallist at the 2008 Beijing Olympics. He was one of Norway's leading medal hopes for the London Olympic Games starting on July 27. The Olympic Committee and Norwegian Swimming Federation said in a statement: "He died suddenly, without warning on Monday evening local time while with the swimming team in Flagstaff, USA." Per Rune Eknes, president of the Norwegian Swimming Federation said: "My thoughts go first and foremost to his family in Oygarden. This is the toughest day the sport of swimming in Norway has ever had. Dale Oen won his world title last year in the immediate aftermath of the massacre of 77 people by far right fanatic Anders Behring Breivik in central Oslo and on the island of Utoeya. He had struggled with his emotions after attacks that sent Norway into national mourning, touching the Norwegian flag on his swimming cap every time he entered the pool deck.