For the first time in its 33-year history, a participant in the world renowned "Escape from Alcatraz" died during the event.

That Ross Ehlinger, 46, died Sunday during the swim portion of the event held in the frigid San Francisco Bay amid 6-foot (1.8-meter) swells and a powerful outgoing tide raised questions about what effect the tough conditions had on his death. This year's event was held on Sunday rather than in June to accommodate the America's Cup sailing race.

The answer appears to be that the father of three from Austin, Texas, may have had an underlying health problem exposed in an especially grueling triathlon.

The San Francisco medical examiner is still investigating the cause of death.

But race organizers and a heart surgeon that participated in the race speculated that the attorney succumbed to an underlying health problem rather than being a victim of the conditions or drowning. Ehlinger was wearing a wetsuit.

"I bet the man had a health problem," said Dr. Lawrence Creswell, a University of Mississippi researcher who has participated in several "Escape" triathlons. "I would bet that there's a heart problem and not a drowning problem."

Creswell chaired a committee appointed by triathlon's governing body to research why 43 participants died in events between 2003 and 2011. That study found that 30 of the 45 triathlon deaths that occurred during that period happened during the swimming portion. All 30 were thought to be the result of "sudden cardiac death."

Still, Creswell said conditions were rough and the water was cold Sunday. Last year, the water was 60 degrees Fahrenheit (15.5 degrees Celsius). But in 2011, the water temperature was 52 degrees F (11 degrees C). The San Francisco Bay is notoriously finicky and conditions change often and quickly regardless of the time of year.

"It was a very challenging swim," Creswell said.

Still, Creswell said the temperature of the water probably didn't have an effect in a body of water that is nearly always hovering in the 50s F (10 to 15 C).

"No one has died in the race in 33 years," he said.

Race organizer Bill Burke said they plucked about 150 swimmers who were off course or struggling from the water and "repositioned" all but about 10 participants back in the water to complete the race.

"We pick them up and relocate them on the course," he said. He said organizers had 130 "assets" on the water, including several kayakers and dozens of jet skiers watching over the swimmers.

Burke said that it's common to "reposition" 60 or 70 swimmers each year and that usually only about four or five quit the race completely. He attributed the higher numbers of those quitting to the cold and windy 53 degree F (11.5 degree C) temperatures on shore.

"It was miserable," he said of the end of the 1.5-mile (2.4-kilometer) swim when the roughly 1,700 participants were emerging from the water.

Burke said that growing popularity of triathlons generally, and a few iconic races in particular, are attracting an increasing number of athletes who may have an underlying medical condition or who are simply not in shape.

"Escape from Alcatraz is the most iconic triathlon there is," said Burke, whose company also manages New York's Ironman U.S. Championship and other popular events.

"I have always wanted to come to San Francisco to race in this infamous triathlon," said Javier Gomez, the triathlon's winner. "The course was tough with cold water, strong currents and a great field of competitors."