Sudden death in runners

Sudden death in athletes refers to a sudden cardiac arrest occurring during exercise or within the hour following it, in an apparently healthy person. In running, it is most often linked to an undiagnosed underlying cardiovascular cause.

It is generally caused by a severe cardiac arrhythmia, most often ventricular fibrillation, which prevents the heart from pumping blood effectively. Without immediate treatment (chest compressions and defibrillation), loss of consciousness occurs within a few seconds. Even though running remains an extremely beneficial activity for health, it is important for runners to know the risk factors, the warning signs and the means of prevention.

Sudden death in athletes results from a sudden failure of the heart’s electrical system. A severe cardiac arrhythmia, most often ventricular fibrillation, disorganises the electrical activity of the ventricles: the heart then stops pumping blood effectively to the rest of the body, leading within a few seconds to loss of consciousness and then to cardiorespiratory arrest in the absence of immediate treatment.

Sport-related sudden death remains exceptional: studies estimate its incidence at around 1 case per 50,000 to 100,000 athletes per year. In runners, it most often occurs during competitions, during intense efforts, in athletes with an unknown heart condition. Despite this very low risk, the media coverage of certain cases makes this a particularly worrying subject for athletes.

The causes vary according to the athlete’s age.

In runners under 35

The causes are often related to congenital heart abnormalities: hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia, coronary artery anomalies, or inherited cardiac electrical disorders. These diseases can remain silent for many years.

In runners over 35

The most common cause is coronary artery disease: intense exercise can cause an atheromatous plaque in a heart artery to rupture and trigger a heart attack or a fatal arrhythmia. The classic risk factors are smoking, hypertension, high cholesterol, diabetes and a family history of cardiovascular disease.

Aggravating factors during exercise

Certain situations increase cardiovascular stress while running: very intense effort or competition, significant dehydration, extreme heat, a recent viral infection, severe fatigue, use of stimulants. Returning to sport too quickly after an illness can also increase cardiac risk.

Certain symptoms should prompt you to see a doctor before continuing training: chest pain during exercise, unusual breathlessness, feeling faint or dizzy during sport, marked palpitations, or loss of consciousness, even brief. Feeling unwell during a running session should always be taken seriously.

Have a medical check-up

A regular medical examination is recommended for athletes, particularly before resuming a sporting activity, after the age of 35, or if there is a family history of heart disease (clinical examination, electrocardiogram, exercise test if necessary).

Adapt your training

A gradual increase in training load reduces cardiovascular stress: increase distances progressively, respect recovery times, and avoid competitions when tired or ill.

Listen to your body’s signals

Chest pain, feeling faint or palpitations should always lead you to stop exercising and see a doctor.