The attention shifted from the athletes on the sand to a man pulled unresponsive from the ocean during Sunday's "Never Quit Never" event.
According to Jacksonville Beach police, lifeguards and firefighters responded to a report of a swimmer in distress at the beach at the foot of Beach Boulevard at 11:40 a.m.
Witnesses say 43-year-old Sydney Graham was brought to shore by participants in the Trident Challenge -- a 500-meter ocean swim, a crawl through the sand, pull ups and paddleboarding.
Ocean rescue personnel who were contracted by Never Quit Never had jet ski's in the water, lifeguards on surfboards and buoys out at sea directing swimmers where to go.
Paramedics performed CPR on the sand for several minutes, then transported him to Baptist Beaches Medical Center, where he died at 12:40 p.m.
"A few years ago an older guy just died. I've seen a younger person just drop during a triathlon in Fernandina a couple years ago," said former Triathlete Dave Hotchkiss.
An autopsy will reveal whether Graham suffered from a medical emergency in the water before he went under Sunday.
First Place Sports' Doug Alred told Channel 4 too often people aren't prepared to take part in longer races like Never Quit.
"It's something you never want to see but it does happen unfortunately. We had all the people in place to try to prevent something like this. We helped Ocean Rescue in their response in the quickest and most efficient manner possible," said Lt. Richard Ghiotto, a Jacksonville Beach lifeguard.
Graham is from Houston. His family was on the beach as efforts were made to revive him.
"I work with him, and he wanted to do this event with us. We are in shock right now and we want the family to identify who he is, if they wish to," said a friend of Graham.
"I think those occurrences would happen if they were walking in grocery store. Because often times it's aneurysm or heart attack ," said Hotchkiss
Before swimmers entered the water in the Trident challenge, they were urged to look out for other swimmers who may be in distress.
"I think all of our lifeguards did the best that we could in this situation, and we all are hoping that this man really pulls through," Ghiotto.