Are Triathletes At Higher Risk Of Cardiac Events?

Being a multiple-stage competition involving the completion of 3 continuous and sequential endurance disciplines, triathlon usually involves swimming, cycling, and running over various distances. It began in 1970s and has become an increasingly popular endurance activity worldwide. A standard Olympic triathlon involves a 1.5 km (0.9 mile) swim, followed by a 40 km (24.8 mile) bike ride and a 10 km (6.2 mile) run.

Obviously, triathlon puts unusually high demands on the body, especially the heart. Does it mean that triathlon is a dangerous sport?

Recent study by German researchers reported that men who compete in triathlons could put their heart at risk. After examining 55 male triathletes averaged 44 years old, and 30 female triathletes averaged 43 years old, the researchers found that 18 percent of the men had a condition known as myocardial fibrosis, but not the female triathletes. Myocardial fibrosis is scarring of the heart, and it usually affects the pumping chambers and can progress to heart failure. The findings were presented at the Radiological Society of North America annual meeting between Nov 26 and Dec 1, 2017 in Chicago.

The clinical relevance of these scars is currently unclear but they might lead to future heart failure and arrhythmia (irregular heartbeat). The researchers explained that higher exercise-induced systolic blood pressure may result in greater myocardial mass and more exercise might expose the athlete to a higher risk of myocarditis, or inflammation of the heart muscle. These factors, together with repeatedly increased stress of the left ventricular wall due to exercise, could injure the heart muscle. Meanwhile, the presence of testosterone may be one of other factors that explain the difference in myocardial fibrosis risk between male and female triathletes.

Findings presented at meetings should be considered preliminary because it has not been subjected to the scrutiny given to research published in medical journals. Previous studies have, however, found myocardial fibrosis in elite athletes.

Latest American data also indicated that triathletes may be more likely to die suddenly and suffer a fatal trauma or cardiac arrest than previously thought. A study of more than 9 million participants over 3 decades found that deaths and cardiac arrests struck 1.74 out of every 100,000 competitors. The findings were published October 17, 2017 in the ‘Annals of Internal Medicine’.

During the study period from 1985 to 2016, 135 people died suddenly or had a cardiac arrest. This included 107 sudden deaths and 13 race-related cardiac arrests that people survived because of prompt emergency medical attention. The victims were 47 years old on average, and 85 percent were male.

Autopsy data showed that clinically silent cardiovascular disease was present in an unexpected proportion of decedents. The incidence of cardiovascular events was much lower in female triathletes, 3.5-fold less than in men. Death risks also raised with age. Among men 60 and older, 19 participants died or suffered cardiac arrest out of every 100,000 competitors.

Hence, it is advisable for participants of triathlon or other sports to get medical checkup to see if they have any risk before participating. This is particularly important for middle-aged and older men.