Citing busy schedules, both China's Education Ministry and its general sports administration declined AP's requests for interviews.
Wang Fangchuan, a sports professor at Fudan University in Shanghai, sees the disregard of health as the "mark of a society in pursuit of academic achievements."
"We are walking on one leg," Wang said.
The pressure for academic excellence begins early in Chinese grade schools, which do not have a tradition of competing in sports against neighboring schools. The national goal of earning Olympic gold medals further separates sports from ordinary schools, because promising young athletes and resources are siphoned off to special sports schools nationwide.
"We have this strange phenomenon. Outside, we are showing off muscles, but at home we are panting," popular blogger Li Chengpeng wrote last summer, when China's Olympic athletes in London raked in 38 gold medals — second only to the United States.
"Outside, the red flags are flying. At home, the red lights are going up," Li wrote.
In Wuhan, 24-year-old police officer Yu Meng said he gave up on college and went to the police academy instead after his passion for soccer cost him academically in high school.
"On the playing fields are those with lackluster academic scores. Those with excellent scores are all in classrooms," Yu said. "Under the current education system, you cannot have both, and most prefer studies to exercising."
Xiao, the Tsinghua student, constantly did schoolwork while a high school senior in northern China's Shanxi province, rising at 7 a.m. and going to bed after midnight every day, to better prepare herself for college entrance exams.
"The school no longer required us to run in the senior year," she said, adding that her weekly physical activity consisted only of a bit of badminton with friends.
The long hours of studying paid off. School officials awarded her family 20,000 yuan ($3,200) and an LCD television when she scored high enough in the exams to get into the prestigious university.
Sports educators at Tsinghua say they feel obligated to make up for missed opportunities in high school by planting the habit of exercise.
"We have elite education here," said Ma Xindong, the university's head of physical education. "If you live longer, you can contribute more to the society."
Tsinghua goes beyond the standard requirement of a 1,000-meter run and makes its male students run 3,000 meters for its fitness tests.
Sophomore Xu Sicheng, who had never run such a long distance before coming to Tsinghua, said he and his classmates were "shocked" to learn of the school's grueling requirement.
"We thought it was a mission impossible!"