QINGDAO, March 25 (Xinhua) -- Sun Yang had no smile, no bright-color swim trunk, and there was no cause for celebration.

Wearing a dark blue swim trunk, Sun stormed to victory in 3:43.73, a world best result this season in the 400m freestyle and lifted the first title at these Chinese National Championships, held from March 24 - March 31.

The Chinese Olympic champion stood in mourning for his friend Kenneth To after the victory and urged every competitive swimmer to live a healthy lifestyle.

Kenneth To, who holds 16 records for Hong Kong, China, lost his life at 26 due to a heart problem after he collapsed following a training session in the United States on March 18, 2019.

"I was in a shock when I heard that my friend Kenneth had passed away. I couldn't stop my tears. His dream was to swim his best at the Olympic Games. I just wanted to continue his dream," Sun said as he choked up.

Kenneth was a winning relay member with Sun two years ago at the quadrennial Chinese National Games in Tianjin, and also became a close friend with Sun when he trained in Hong Kong.

"We just had dinner together last December after we competed in the FINA Short Course World Championships in Hangzhou. I respect him and miss him," Sun said.

"Professional athletes are indeed in high-risk occupations, especially competitive swimmers. We are under great pressure in terms of physical and mental challenges," said Sun, 27, who will swim 200, 400, 800 and 1500m freestyle during the eight-day national championships in Qingdao.

"I felt sorry that Japanese swimmer Hagino Kosuke stopped training and competition recently. We are both rivals and good friends. I just wish that everyone can live well and healthy. That is the most important thing in life," he said.

"I trained very hard this winter but I am not in good shape right now. I just want to challenge myself and take this meet as the rehearsal for the Gwangju World Championships in July. I want to get used to the world-level competition pace as early as possible," said Sun.