The survey shows that half of the students have high blood pressure and the number of overweight students is double that of five years ago, according to the survey jointly conducted by the Ministry of Education, Ministry of Health and State Sports Administration.

It also indicates a physical decline of Chinese students in vital capacity, speed and strength while their height and weight continue on an upward curve.

The Beijing Municipal Commission of Education says elementary and secondary students in Beijing have on average more than eight classes a day, double the amount of class hours allowed by state regulations.

"More than 60 percent of head teachers of elementary and secondary schools in Beijing admit that the students are overloaded with school work and many schools cannot let students have physical education every day," said Du Songpeng, deputy director of the commission.

Some schools cancel some sport events which they think are too dangerous in order to avoid accidents, which makes it difficult to improve the physical condition of the students, Du said.

The commission has ordered schools to set aside sufficient time for student exercise, which will be listed as one of the criteria when evaluating schools' performance, he said.