Laurent Vidal, who competed in the last two Olympic triathlons, died overnight at age 31.
Vidal suffered a heart attack, according to European reports.
The Frenchman previously suffered a heart attack while training last year and retired from the sport. Vidal finished 36th at the Beijing 2008 Olympics and fifth at the London 2012 Olympics.
“Laurent was an unforgettable presence, touching the lives of anyone who met him with his positive outlook and incredible energy,” International Triathlon Union president Marisol Casado said in a press release. “He was constantly coming up with new ideas to take our sport to the new level, pushing the envelope in everything he did.”
Vidal coached and was engaged to New Zealand triathlete Andrea Hewitt, who finished second to American Gwen Jorgensen in the 2015 ITU World Series season standings.