Interesting article. They recommend better screening of participants.
In Triathlons, Swimming Poses Greatest Risk of Death
By John Gever, Senior Editor, MedPage Today
Published: April 06, 2010
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner Earn CME/CE credit
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Most triathlon participants who drop dead during the competition do so in the water, researchers said.
Investigation of 14 sudden deaths among triathletes from 2006 to 2008 showed that all but one occurred during the swimming portion, reported Kevin M. Harris, MD, of the Minneapolis Heart Institute of Abbott Northwestern Hospital in Minneapolis, and colleagues.
No deaths occurred during running events. One participant died after a bicycle crash.
All the swimming deaths were officially attributed to drowning, "but seven of nine athletes with autopsy had cardiovascular abnormalities identified," the investigators wrote in a research letter appearing in the April 7 Journal of the American Medical Association.Action Points
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Explain to interested patients that triathlons typically involve strenuous exertion that may contribute to sudden cardiac death in patients not in top physical shape.
Explain that a cardiovascular stress test and other evaluations may be warranted for individuals seeking to train for or participate in triathlons for the first time.
Harris and colleagues recommended that triathlon organizers set minimum achievement standards for participants, "including swimming proficiency."
The apparent cardiovascular risk should motivate individual competitors to be evaluated before racing, but mass screening of participants is probably impractical, the researchers also noted.
The JAMA letter updates data reported by Harris at the 2009 American College of Cardiology annual meeting.
He and colleagues reviewed data on some 959,000 participants in events sanctioned by USA Triathlon, the major standard-setting organization for such events, from January 2006 through September 2008. The data were collected by this group and the U.S. Registry of Sudden Deaths in Athletes.
The 14 deaths translated to a rate of 1.5 per 100,000 participants, the researchers reported.
A total of 2,971 events were included in the analysis. Distances were relatively short in 45% of events, medium in 40%, and long in 15%.
For the swimming portions, these categories were defined as less than 750 meters for short events, from 750 to 1,500 meters for medium distances, and more than 1,500 meters for long triathlons.
Six of the swimming deaths happened in short events, four in medium-distance swims, and three in long races. Two of the latter were so-called Ironman triathlons in which the swims are 3,860 meters (2.4 miles).
Death rates per 100,000 participations in these swim distance categories were:
Short: 1.4 (95% CI 1.1 to 3.1)
Medium: 1.0 (95% CI 0.4 to 2.8)
Long: 2.8 (95% CI 1.0 to 7.5)
In eight of the fatal swimming incidents, the participants were noted to have called for help; five were found motionless in the water after other swimmers had moved on.
Although 41% of participants were female, only two of the 13 swimming deaths involved women.
Besides gender, another contributing factor was the number of competitors in a given race, according to Harris and colleagues.
The mean number of participants in triathlons in which an athlete died was 1,319 (95% CI 1,084 to 1,584), compared with 318 in races without deaths (95% CI 302 to 334), they reported.
"Because triathlons begin with chaotic, highly dense mass starts, involving up to 2,000 largely novice competitors entering the water simultaneously, there is opportunity for bodily contact and exposure to cold turbulent water," Harris and colleagues wrote.
They also noted that triathlon swimmers in distress may not attract attention as quickly as a troubled bicyclist or runner.
One large study found a death rate of 0.8 per 100,000 among marathon runners, half that in the current triathlon study.
In the seven dead swimmers with autopsy findings showing cardiovascular abnormalities, six had mild left ventricular hypertrophy. Their maximum cardiac wall thickness was 15 to 17 mm and the mean heart weight was 403 grams (SD 77). One of these individuals had a clinical history of Wolff-Parkinson-White syndrome.
The seventh athlete was found to have a congenital coronary arterial anomaly.
Harris and colleagues noted that their data may not have included every athlete who died during a triathlon, as such deaths are not subject to mandatory reporting. The study was also limited to events sanctioned by USA Triathlon, leaving out an unknown number of other competitions. Finally, some athletes likely participated in multiple events included in the study.
The Hearst Foundation supported the study.
No potential conflicts of interest were reported.
Primary source: Journal of the American Medical Association
Source reference:
Harris K, et al "Sudden death during the triathlon," JAMA 2010; 303: 1255-57.
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Related Article(s):
ACC: Triathletes More Likely to Die Suddenly Than Marathoners
