Ironman 70.3 competitor dies of heart attack on Sunshine Coast

A 39-year-old man has died of a heart attack while competing in an ironman event on the Sunshine Coast this morning.

The incident happened during the swim leg of the Ironman 70.3 Sunshine Coast Triathlon at Mooloolaba about 7am.

A spectator on the beach who noticed the man in trouble swam out to try and help but the swimmer was unresponsive when he reached him, the Courier Mail reports.

Paramedics performed CPR on the man but he was pronounced dead at the scene.

Ironman Asia Pacific CEO Geoff Meyer said it is believed the man suffered a heart attack during the event.

"He was treated at the scene by water safety officers and qualified medical staff."

"The medical team worked on the gentleman for over half an hour. He was pulled out of the water."

"It was a tragic circumstance for all involved, with efforts now concentrated on supporting the family in this difficult time, as well as event personnel who were involved."