TAIPEI (Taiwan News) — A young swimmer participating in this year’s annual Sun Moon Lake Swimming Carnival passed away on Sunday (Sept. 24) morning due to sudden cardiac arrest.

A 25-year-old man, surnamed Yuan (袁), called for assistance after swimming about 100 meters as he began to experience a heart attack. Medical responders pulled him from the water, and after being loaded onto the rescue vessel, he stopped breathing.

They took him to a nearby first aid station at approximately 9:30 a.m. but despite receiving CPR from first responders, he remained unresponsive. He was then rushed to Puli Christian Hospital, where he was pronounced dead, reported LTN.

Doctors at the hospital tried to revive Yuan for an additional 30 to 40 minutes, but the young man could not be revived.

Medical professionals speculated that the temperature difference between the hot air at 27 degrees Celsius and the cold water may have caused difficulty for some swimmers, reported UDN. Yuan was reportedly a large individual and the rigorous physical activity may have sparked the cardiac arrest.

A forensic examination will determine whether there were any other specific factors that contributed to Yuan’s death, per LTN. With the exception of Yuan, no serious injuries or incidents were reported at this year's Sun Moon Lake swim.