NAPLES, Fla. – Authorities say a Colorado man died after losing consciousness during a triathlon at a Florida park.

The Naples Daily News reported that James Treadwell, 75, died Sunday following the race at Sugden Regional Park in East Naples.

The Collier County Sheriff's Office said that paramedics and others tended to the man at the shore of a lake. Witnesses say he went underwater near the end of the swimming section, and two other participants had to drag him to shore.

The paramedics began CPR, and he was rushed to a nearby hospital, where he was pronounced dead. It wasn't immediately clear what caused Treadwell to collapse.

The triathlon included a quarter-mile swim, a 15-kilometer bike ride and a 3-mile (5-kilometer) run. The event's website says the swimming portion was the first part of the race.