In the 1500 metre freestyle, where he was the two-time defending champion, Sun withdrew from the competition, later citing heart problems during a warm-up. "I feel very sorry that I couldn't be present for the 1500m", Sun told reporters. "I didn't feel good in my heart. Today I felt really uncomfortable at the pool during my warm-up and I had to give up the idea of competing. I feel really sorry about that."
