He and Loevberg said Dale Oen had trained in Flagstaff many times and loved visiting the Grand Canyon and scenic Sedona, famed for its red-rocked mountains.
This trip, they said, Dale Oen was training five to six hours a day and didn't travel around because he was so focused on London.
Several of Dale Oen's teammates reached in Flagstaff declined to comment on his death.
In his last tweet Monday, Dale Oen said he was looking forward to going back home: "2 days left of our camp up here in Flagstaff,then it's back to the most beautiful city in Norway.. (hashtag)Bergen."
Dale Oen was born in Bergen, Norway's second largest city, on May 21, 1985. He was the second son of Mona Lillian Dale and Ingolf Oen.
He started swimming at age 4 and said on his website that the sport "came very easy and natural for me." He won silver in the 100 breaststroke at the 2008 Beijing Olympics.
He is the second high-profile athlete to die from cardiac arrest recently, after Italian soccer player Piermario Morosini collapsed on the field during a Serie B game for Livorno last month. That incident came just a month after Bolton midfielder Fabrice Muamba also collapsed during a game but survived.
Dale Oen is the second prominent swimmer to die in less than two years.
American open-water star Fran Crippen died during an October 2010 race in the United Arab Emirates. His autopsy listed the cause of death as drowning combined with heat exhaustion, leading to calls for improved safety measures in that swimming discipline, which involves grueling events that are usually held in oceans and lakes. Dale Oen competed in traditional pool swimming.
Cornel Marculescu, the executive director of FINA, said Tuesday the organization planned to honor Dale Oen.
"We will figure something out, because he was a great champion," said Marculescu, adding that he had not yet spoken with FINA's medical commission. "We have to find out more details about what happened first."
Dale Oen was considered the leading challenger to Japanese star Kosuke Kitajima, who will be going for his third straight sweep of the 100 and 200 breaststroke events in London.
"In shock over the passing of a dear friend and great rival. RIP Alex," Kitajima tweeted.
American breaststroker Brendan Hansen said Dale Oen's death brought back painful memories of Crippen.
"You see a kid in his prime and never think anything like that could happen," Hansen told The Associated Press in a telephone interview. "All of a sudden, they're gone. You can't help but feel sad. It looks so unfair. We're supposed to be these amazing athletes. It's just a shame."
Hansen said he still remembered the look on Dale Oen's face before they raced at the Beijing Olympics.
"The ready room can be stressful and tense, but he was just kind of enjoying it — laughing and smiling," Hansen said. "You could tell he was just like a little kid excited to race. I knew he loved it."
AP Sports Writers Andrew Dampf in Rome, Pat Horne in New York and Paul Newberry in Atlanta and AP writer Amanda Lee Myers in Phoenix and AP photographer Matt York in Flagstaff contributed to this report.
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