Two schoolboys have collapsed and died during a mandatory gym class while wearing face masks.

The boys were taking part in a physical education examination at their school in China after concerns were raised over student fitness following the coronavirus lockdown.

7News reports: “Parent Mr Li, whose son attended Dancheng Caiyuan Middle School, said CCTV images of the incident showed his boy doing laps of the athletic track for his PE class when he fell backwards on 24 April.”

Li told the outlet: “It happened within two to three minutes during his physical training class.

“He was wearing a mask while lapping the running track, then he suddenly fell backwards and hit his head on the ground. His teacher and classmates tried to pull and drag him back up.”

A local hospital suspected the boy died from ‘sudden cardiac arrest’. His father said he suspects it was because he was wearing a mask.

Cao Lanxiu, professor at Shaanxi University of Chinese Medicine said it was unlikely the mask caused the boy to suffocate.

“I don’t think mask-wearing has caused this sudden death,” Cao said, although she admitted it was impossible to say without an autopsy which the family opted against.

The other student, from Changsha’s Xiangjun Future Experimental School, is also thought to have died from breathing difficulties. At the time, he was participating in a 1,000-metre running test while wearing a face mask.

Though it’s not yet confirmed whether the masks played a role in either death, several schools in Tianjin and Shanghai have cancelled physical education examinations, the New York Post reported.

Face masks are mandatory in Chinese schools.