QINGDAO, China, April 15 -- Triple Olympic champion Sun Yang insisted that he would try his best to compete at 2020 Olympic Games, but the 25-year-old freestyle specialist did hesitate about quitting the pool after last year's Rio Olympics.

"Day after day, no matter summer or winter, you have to get up so early and swim in the pool repeatedly. Everybody might go nuts sometime," said Sun who just went under the anti-doping test after claiming his first national title of the men's 100m freestyle at the Chinese Swimming Championships on Friday.

He had bagged home four gold medals since the opening of the competition on Monday, winning the 200m and 400m freestyle both in the world's fastest results of the year so far. And the 1,500m victory seems at his fingertips as he is the world record holder and two-time world champion of the event.

Competing in all of the five individual freestyle events means Sun has to spend more time for preparation and recovery every day.

"I left the Aquatic Center at 10p.m. yesterday. All the lights were turned off and all the gates were shut. We had to find a back door to go out," said Sun.

Sun could be regarded as the most successful Chinese swimmer as the three-time Olympian took the gold medals of the 400m and 1,500m freestyle at 2012 London Games and clinched the title of the 200m freestyle four years later in Rio.

But the honors never come easy. While preparing for Rio Olympics, Sun's metatarsal bones of his left foot fractured twice and he hardly trained for start and turn in the last six months ahead of opening of the Games.

"I talked about my future with my father after Rio Olympics. The career is so tough and I was thinking maybe I could only hang on for one or two more years," said Sun. "It's hard for an athlete to keep fighting for a long time and only the strong-minded ones could stand the trial."

"As a swimmer, I'm not young. But I still want to make more achievements within my reach," said Sun. "I'm touched when I see so many fans come to watch my races and I hope that they could be happy."

The period of four years might be a snap in one's life, but is quite a strenuous journey for an athlete preparing for an Olympic Games.

Sun's father Sun Hongquan told reporter on Thursday that Sun Yang even cried more than once after torturous training ahead of Rio Olympics. "Sometimes he did want to quit, because he had reached the limits of his strength."

But when Sun wants to make more efforts for Chinese swimming, he believes he could keep fighting in the pool until his fourth Olympic Games.

"I hope I could attract more people to be involved in swimming and to love the sport through my performance," said Sun.