Co-authors of the largest study to date of fatalities in U.S. amateur triathlon races say it underscores the need for middle-aged male participants, in particular, to undergo thorough evaluation for cardiovascular health.
Of the 109 deaths reviewed in the Minneapolis Heart Institute Foundation study, which analyzed data from races between 1985 and 2015, 85 percent were men. The average age of the entire group was 47, and in a closer look at recent deaths (2006-15), the average age was 50, or 12 years older than the average age of all participants during that time.
The majority -- 76 deaths, or 70 percent of the total -- occurred during or upon exiting the initial swim leg. The bike leg accounted for another 19 deaths, mostly in crashes. The balance came during the running leg, which is last in the event. About half the total fatalities were in shorter "sprint" triathlons, which attract more newcomers to the sport and more participants overall.
Lead researcher Dr. Kevin Harris told ESPN.com that his team was able to review autopsy reports for 46 of the 109 deaths. In the remainder, autopsies either were not performed or were not available due to state privacy laws. Some medical histories and other data were culled from questionnaires filled out by family members.
Just over half the autopsies revealed evidence of pre-existing cardiovascular disease, which is more apt to affect men earlier in life than women, Harris said. The deceased were on average more than 10 years older than male participants overall, he said, adding, "It speaks to the fact that there may be a subset of triathletes who may benefit from screening.''
For the years 2006-15, when triathlons made huge gains in popularity in the United States, the incidence of death was 1.5 per 100,000 in events sanctioned by USA Triathlon (the sport's national governing body), Harris said.
A breakdown of participation by gender was not available for the entire 30-year span of the deaths in the study, but the statistics are notably lopsided, Harris said.
"You do wonder if men take more chances, '' he said.
Harris emphasized that in many cases, it's impossible to reconstruct whether a sudden cardiac arrest preceded drowning, or whether a swimmer's distress in the water led to a cardiac event.
"A pathologist looking at a human heart after a person died can only draw so many conclusions,'' Harris said.
"What can an athlete do? Certain of them should screen. Listen to your body. Be realistic about open water [swimming] and train adequately.''
Dr. Larry Creswell, a cardiothoracic surgeon and associate professor at the University of Mississippi, said there is no "one size fits all" cardiac evaluation for new or older triathletes. Rather, he said, each participant should consult with a physician to discuss risk factors and appropriate screening.
USA Triathlon did not fund the study, but cooperated with Harris by contacting some surviving family members. Harris found others through public records. There is no central clearinghouse of information on such deaths, and USAT keeps records only for events it sanctions.
Creswell, a triathlete himself, has served in several unpaid roles on USAT committees and educational programs and chaired a more limited review of fatalities for the federation in 2012. He also was retained by the organization as a defense expert in a wrongful death lawsuit. However, Creswell said his work with Harris was independent of the federation, and he has no plans to formally present the research to USAT.
The researchers also reviewed media accounts of 12 triathlon participants who were resuscitated after cardiac arrest -- five of them pulled from the swim course. Such cases should be a priority for future study, Harris said.
"The next big area is how to improve resuscitation efforts and what allows for a successful resuscitation,'' he said.
Creswell agreed, saying: "We can learn from the near misses.''
Event organizers must focus on having safety personnel trained to spot swimmers in distress, rescue them to a place where CPR can be performed as quickly as possible, and get them advanced medical treatment such as defibrillation "within minutes,'' to give them a chance, he said.
"More than anything else, you should answer how you're going to do those three things,'' he said.
Harris and Creswell presented a summary of their findings Saturday at an American College of Cardiology conference in Chicago. A more detailed scholarly article is being prepared for publication later this year, said Harris, who led a previous study on a much smaller sample of triathlon fatalities.
A 2013 Outside the Lines investigation identified 52 deaths in U.S. triathlons from 2007 to 2013, 44 in the swim leg. The toll peaked in 2012 when 14 people died, all but one in the swim leg, according to a database maintained by OTL. Most of the deaths in the time span OTL examined occurred in events sanctioned by USA Triathlon. Some survivors called for better enforcement of safety standards, the execution of which is left up to individual race directors, and more attentive administrative follow-up after fatalities.
Since the OTL story was published, at least two wrongful death suits that named the federation and/or race organizers as defendants have been settled out of court. USAT has instituted water temperature guidelines, and many race organizers have eliminated so-called "mass" starts in favor of more controlled conditions to reduce the stress level and physical contact experienced by participants.
USAT spokeswoman Lindsay Wyskowski said the governing body consults regularly with race directors on safety issues.
"Safety is paramount to what we do here, and these are ongoing conversations,'' she wrote in an email.