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Sudden Death During a Triathlon: Are You at Risk?

See your doctor if you experience these symptoms

Sudden Death During a Triathlon: Are You at Risk?

Triathlons push the body to its physical limits with swimming, biking and running events. Some groups of people are more at risk than others for sudden death — any kind of death that happens unexpectedly — while participating in these challenging events, recent research shows.


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The study, led by researchers from the Minneapolis Heart Institute Foundation in Minnesota, found that

  • Deaths and cardiac arrests during a triathlon are not rare events, and the incidence was about 1.7 per 100,000 people.
  • Most deaths and cardiac arrests occurred in men who were middle-age and older, and first-time participants.
  • Men had a significantly higher risk than women.
  • Most sudden deaths in triathletes happened during the swim segment.
  • Underlying heart disease or a heart abnormality was present in an unexpected proportion of the people who died.

Researchers studied data from about 9 million triathlon participants over a 31-year period. They found a total of 135 sudden deaths, resuscitated cardiac arrests, and trauma-related deaths stemming from collisions during an event. Fifteen trauma-related deaths occurred during the bike segment.

Of the 135 deaths, 107 were sudden deaths and 13 were race-related cardiac arrests in persons who survived because of timely cardiopulmonary resuscitation and defibrillation.

How to reduce the risk

The researchers say that improving safety measures at triathlon events would help to reduce the risks of triathlon competition. Some that the study says have been put in place for events sanctioned by the USA Triathlon organization include:

  • Minimum standards for medical presence at races, water quality, on-water rescuers, and prospective notification of local emergency medical services and hospitals.
  • Rules regarding wetsuit use that are designed to prevent hypo- or hyperthermia during the swim segment.
  • Ensuring safe water temperatures for races.
  • Elimination of mass starts at Ironman events with more than 2,000 competitors would allow easier recognition of troubled or lifeless participants during the swim segment.


The fact that some men are at greater risk for sudden death during a triathlon points up the need to consult your doctor if you notice any heart-related symptoms while preparing for a race, says sports cardiologist Dermot Phelan, MD, PhD. Dr. Phelan did not take part in the study.

“If you are going to participate in a triathlon, it’s very important that you pay attention to your symptoms,” he says. “If you are getting chest pains, shortness of breath, palpitations or lightness in the head when you’re participating, you should see a cardiologist who has some experience in dealing with athletes.”

Proper training is important before a triathlon, Dr. Phelan says. He stresses that people, particularly older men, pay attention to heart disease risk factors like cholesterol, blood pressure and blood glucose before signing up for any type of endurance event.

Complete results of the study can be found in Annals of Internal Medicine.

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