LAS VEGAS (FOX5) — The Clark County coroner said a 13-year-old who died during football practice in June died from a heart condition.

Chino Yelum Cajetan Nsofor, 13, died from cardiac dysrhythmia, or an irregular heartbeat, following physical exertion, the coroner said.

He also was reported to have “rhinovirus/enterovirus, cardiomegaly, and genetic variant of uncertain significance.”

According to a coroner report, Nsofor participated in 10 minutes of warm-up exercises before telling the coach, “Coach, I can’t do it,” on June 28 at Legacy High School.

He then sat down in the shade to rest and told his sister he could not breathe. He then collapsed, and 911 was called.

While rhinovirus was detected at the time of his death, COVID-19 was not. The report noted Nsofor’s cousin had died at age 16 while playing basketball in Atlanta two years prior.

His death was ruled natural.

“Our thoughts and prayers are with Chino’s family and friends at this difficult time,” the county wrote in a statement Monday.

“It is never easy to lose a valuable life, especially at a young age and we will truly remember this student as part of the CCSD family,” CCSD said in a statement at the time.