Triathlon Safety, Death Risk, and Ironman Mortality Statistics — Triathlete

At Ironman Texas this past April, Brazilian triathlete Mara Flávia Souza Araújo, 38, lost her life during the swim. While death in a community built on the pursuit of health and resilience is tragic, the media response to events like these is notably intense. Sensationalist headlines, like a recent story in the New York Post, go so far as to characterize Ironman racing as “dangerous and deadly,” fueling a narrative that suggests those who participate in such grueling endurance events are taking an unnecessary and “crazy” risk with their lives.

And while any sudden passing is world-changing for those left behind, it is important to put these triathlon deaths in context in a conversation about the safety of the sport as a whole. To understand if the “dangerous” label is justified, we must examine the objective data surrounding mortality in triathlon. In doing so, we can better evaluate how our sport compares to other activities, and identify what can be done to further mitigate the risks faced by athletes in the water and on the road.

Understanding mortality data on triathlon deaths

First, it is important to note that participation in any sporting activity carries with it both risks and benefits. Leading with dramatic stories (such as a cardiac arrest during a swim segment) presents extreme, rare outliers as if they are representative of the average participant’s experience. That can lead to the assumption that it’s safer to stay on the shore.

We know that being sedentary is associated with worse long-term outcomes related to all manner of chronic physical and mental health issues. Being active brings not only improvements in cardiovascular health but also overall benefits, including longer disease-free survival. There are also many intangible benefits as well, such as belonging to a community, social advantages, and personal well-being. It is well accepted that participating in endurance sports has a significant net benefit.

With that said, the risks of sudden death when participating in an endurance activity are quantifiable, and while small, they are not zero. The risk of sudden cardiac death across mass endurance events (running, cycling, and triathlon) is between 0.33 and 0.4 deaths per 100,000 participants per year. The range varies quite a bit across event types, though. For example, among marathon runners, the rate is 0.39-1.01 per 100,000 participants. For the half marathon, the rate is 0.27-0.54 per 100,000, and for triathlon it is 1.74 per 100,000.

Irresponsible reporters will look at these numbers and say “triathlon is three times more deadly than running a half marathon!” But that ignores the fact that both running and triathlon carry a statistically negligible absolute risk. In other words, a rate of 1.74 per 100,000 is 0.00174%. That means out of every 100,000 people who do a triathlon, 99,998.26 complete the event safely. To put it another way: Three times a very small number is still a very small number.

Why the triathlon swim is inherently riskier

Tabloid articles frequently imply that athletes drop dead simply because 140.6 miles is “too hard” for the human body. They paint a picture of someone swimming, biking, or running so hard for so long that their bodies literally wear out and give up on them.

In reality, virtually all triathlon-related deaths stem from pre-existing, undiagnosed cardiac anomalies. Around 70% of triathlon fatalities occur during the swim, and 38% of those deaths are first-time triathletes. Medical research shows this is rarely caused by drowning due to inability to swim or extreme fatigue. This is not the type of drowning attributed to the fatigue of swimming or time spent in the water — something you might hear about after a shipwreck, for instance.

Instead, researchers suggest these events are tied to a condition called Swimming-Induced Pulmonary Edema (SIPE), cold-shock response, or sudden arrhythmia triggered by the combination of cold water, high heart rate, and adrenaline. This, coupled with the inherent logistical difficulty of water rescue compared with on-course automatic external defibrillator (AED) deployment, contributes to the vast majority of triathlon deaths.  To put it more simply: If you were to lose consciousness, even temporarily, while on dry ground, you’d have a greater chance of discovery and survival while help arrives; water does not afford that cushion of time.

Dr. Richard Moon is a pulmonary critical care physician at Duke University in Raleigh, NC, and has studied SIPE extensively. He says that SIPE is a very real issue, but likely overstated as a cause of death in triathletes. Still, it is a very real concern. “SIPE is more commonly seen in cold water immersion but does happen in warm water as well,” Moon told me.

Moon says some of the risk factors for developing SIPE include “swimming in colder water temperatures, overloading oral fluids prior to the swim, hypertension, known left ventricular hypertrophy, and swimming in a more vertical body position that tends to send more blood to the chest.”

In the case of Souza Araújo – who by all accounts was not known to have any cardiac risk factors and who was widely reported to have had a significant respiratory ailment leading up to Ironman Texas – Moon was circumspect without having examined Araújo: “Studies have shown that respiratory infections can increase the likelihood of SIPE. Proteins related to infection were more common in Navy subjects who developed pulmonary edema in tests, suggesting that infection can contribute to the development of SIPE.”

Outside of the swim, a small number suffer fatal injuries from trauma from bike collisions. The remainder are presumed to suffer a cardiac event. On autopsy, though, only 44% have obvious cardiac abnormalities that could be said to directly contribute to death. In the remainder, the cause is uncertain.

What sensationalistic articles like the Post’s rarely mention is the extensive safety infrastructure required for sanctioned triathlon events. Triathlon organizations, including Ironman, have strived to decrease the danger of the swim by eliminating mass starts to reduce athlete anxiety (and increase visibility for safety personnel), increasing water safety personnel on the course, and tightening up regulations around water temperature and wetsuit use to prevent hypothermia or overheating. Races are also required to have medical personnel on site – often, the “med tent” is better characterized as a comprehensive field hospital staffed by emergency physicians, nurses, and paramedics trained specifically in trauma response, hyponatremia, and cardiac care.

Fatality rates in triathlon vs. mainstream sports

We have seen how triathlon does indeed have a higher risk of sudden death than other endurance sports, mainly due to the swim leg, but does this make triathlon “dangerous” or the people who participate in it “crazy?” I would say that nothing could be further from the truth. The reality is that when compared to all sports, the risks of triathlon are not excessive at all.

Both basketball and football are associated with significantly more deaths per year in the United States than triathlon, due in part to environmental factors and in part to undiagnosed underlying cardiac issues in participants. There have not been any accusations that participants in either of these more mainstream sports are “‘crazy”’ to my knowledge.

Framing Ironman as a “dangerous, deadly world” where participants are “willing to risk it all,” as the New York Post does, treats long-distance triathlon like an extreme blood sport or illegal street racing. In reality, the vast majority of amateur triathletes – most of whom are middle-aged professionals, parents, and fitness enthusiasts – train systematically for months, under disciplined heart-rate and load-management protocols.

Practical steps for risk mitigation

While completing a triathlon, much less an Ironman, is an extreme physical challenge that carries inherent risks, poorly researched and sensationalistic articles about triathlon deaths tend to substitute statistical context with dramatic shock value. In reality, when athletes undergo proper medical screening, train appropriately, and follow race guidelines, triathlon is a heavily monitored, statistically safe endurance event.

At the end of the day, being aware of the risks of participation is very important. Taking steps to mitigate those risks to yourself is the next best thing you can do. If you are over the age of 40 or have a family history of sudden cardiac death at an early age, get a baseline screen for cholesterol and, if your doctor thinks it is necessary, more advanced cardiac screening.

If you develop any symptoms of concern – chest discomfort, palpitations, shortness of breath, or fatigue during your training at levels of exertion not commensurate with the symptoms you are experiencing – then seek medical evaluation right away.

And heed both the advice of every coach ever, and this emergency room doc of more than 20 years: During the swim portion of any triathlon, start slow and easy. Do not go from zero to max effort in a short time. Take the first 100-200m just to ease into the swim and find your rhythm. Then, as you have warmed up and slowly raised your effort level, go a little harder and at any sign of something wrong, stop and signal for help.

The only way to eliminate all the risks of triathlon is to not participate in it — but this is the same solution to literally everything in life. Sitting on the sidelines in perpetuity seems a drastic decision, so do what you can to minimize the already low risk and live your life to the fullest – one swim, bike, and run at a time.