Dr Muiris Houston: Ironman deaths highlight dangers of extreme sporting events

The death of two athletes in the same part of a single triathlete event is unusual. Given the difficult weather conditions in Youghal yesterday, could they have contributed to the fatalities during the swim part of the Cork Ironman event?

We know that participating in a triathlon is associated with a higher risk of death. A major US study of more than nine million participants over three decades found that deaths and cardiac arrests struck 1.74 out of every 100,000 competitors.

Researchers found the risk associated with a single triathlon was higher than the annual risk of death for a middle-aged adult in the general population, and also exceeded previous estimates for long-distance running races, including marathons.

The 2017 study, published in the Annals of Internal Medicine, also found that the majority of deaths occurred in the swim portion of the triathlon, which is the first section of the event.

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Ironman tragedy: What exactly happened during the fatal triathlon in Youghal?

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“During this portion of the race, the athletes likely experience an adrenaline surge as they enter the water and are competing in close proximity to other athletes, and in some cases with environmental conditions that are difficult to prepare for,” the lead author told Reuters.

“We don’t understand the exact cause of death in each athlete, and some swim deaths may be related to drowning.”

The postmortems being carried out on the deceased athletes should be able to identify the cause of death.

[ Youghal Ironman: Minister calls for full investigation into deaths of two competitors ]

Sudden arrhythmic death syndrome – due to the acute onset of a chaotic rhythm in the heart – is a possible cause. Heart muscle disease, problems with the heart’s electrical conduction system, or coronary artery disease may emerge as underlying conditions.

A potentially more specific link to their deaths occurring in the swim part of a triathlon is a condition called swimming induced pulmonary oedema. Originally thought to be associated with heavy immersion in cold water, the most recent research suggests it can also occur in warm tropical waters and swimming pools.

High pressure in the pulmonary vessels causes an abnormal leakage of fluid into the air sacs of the lungs, leading to difficulty breathing and what is sometimes described as “drowning from the inside”.

Do triathletes have to be medically examined and declared fit to take part in the gruelling events?

A medical “fitness certificate” is mandatory to participate in athletic events in Italy. The medical examination must include an electrocardiogram. But in many other jurisdictions a simple medical certificate, without specific assessment, is all that is required to enter a triathlon.

Are there particular warning signs potential triathletes should look out for in terms of medical fitness?

Chest tightness or heaviness, shortness of breath, palpitations and lightheadedness, should be fully assessed by your GP before participating in an Ironman event.