Qing Wenyi, a 17-year-old promising swimming star from Beijing, died in her dormitory in the early morning on Monday.
Qing, representing Beijing Shunyi swimming team, took part in the first National Youth Games in Fujian Province in late October and won gold medals of women's 100m and 200m breaststroke.
After the games, she went back to Beijing and didn't find any abnormality in a routine physical examination conducted on Oct. 28.
Qing resumed training on Nov. 2 in Beijing and went back to her team Sunday afternoon.
She called her mother at 9pm and sent message on Wechat at half past 10.