Amy McCullough, a high school swimmer and former lifeguard from Crystal Lake, Ill., died in the swimming leg of last month’s New York City Nautica Triathlon.

According to a story in the New York Times, McCullough was a fit individual who trained vigorously but ultimately died competing in one of sport’s toughest fitness challenges.

A study published in the Journal of the American Medical Association in 2010 found that contestants are twice as likely to die in a triathlon than in a marathon. According to one of the authors, Dr. Kevin Harris of the Minneapolis Heart Institute, 1.4 per every 100,000 triathlon contestants die, while only 0.8 die in marathons.

“We were aware of deaths in unsanctioned races but decided to leave [them] out to make it a more simple study,” Harris said.

During the study, 13 of the 14 deaths were in the swimming leg.

“I believe some of the deaths that are happening in the water are happening to people who are not ready for the stress of a triathlon,” Harris said. He referred to the chaos of swimming in a crowd of kicking, thrashing fellow swimmers, which can cause a panic attack.

Jason Dement of Fleet Feet S

ports Chicago, 1620 N. Wells St., raced in the 2011 Life Time Chicago Olympic Triathlon and finished the race with a time of two hours, 24 minutes and 56 seconds. He said athletes in the triathlon are the ones who decide how much pressure they can handle. He also advised athletes who are not conditioned or good swimmers to stay away from the triathlon. If t

hey do compete, any resulting injury is “human error,” Dement said.

Dement is also an unofficial trainer at Fleet Feet and trains his friends. According to him, training for the event is usually a 12-week process for experienced runners and bikers, so amateurs should expect longer training.

Both Harris and Dement agreed that simulating the actual swimming portion of the event is the best way to train.

“Being ready does not just mean swimming laps in a pool,” Harris said. “Whatever you can do to replicate the conditions in advance is ideal.”

During the study, Harris and his colleagues were able to perform nine autopsies, and seven revealed cardiac disease. Harris acknowledged  autopsies do not always give the exact reason for death but advised athletes to be careful of competing with a cardiac condition.

The American Heart Association lists warning signs of heart failure: shortness of breath, persistent coughing and/or wheezing, buildup of excess fluid in body tissue, fatigue, lack of appetite, nausea, confusion, impaired thinking and increased heart rate. Harris said those who experience any of these symptoms should see a doctor before competing in a triathlon.

Even though many fatalities occur to middle-age people, Harris believes it is possible for a young athlete to die in a triathlon. The risk increases  when the athlete has an artery in a wrong place or congenital heart condition.

“Young athletes tend to be a little bit healthier than some of the other athletes,” Harris said. But that does not mean they cannot drown, he added.

Heart conditions are not the only cause of deaths in the swimming leg of the race. People who are not adept at swimming in a lake can drown. Harris said, some of the athletes he studied signaled for help, but often assistance is delayed. The rescue is time consuming because the lifeguard must bring the athlete to dry land in most cases.

“With any type of resuscitation, time is one of the most important factors,” Harris said.