Running a marathon may not be so bad for the heart
Contrary to popular belief, running a marathon does not increase the risk of a heart attack. Health experts recommend nevertheless a medical checkup before embarking on such a race.
The image of the marathon runner who collapses, suddenly struck by a heart attack, just before or shortly after crossing the finishing line, is a troubling image that implants a seed of doubt in our minds. These tragic accidents, sometimes relayed by television cameras, are confusing. Sports, and in particular running, are, after all, supposed to improve our fitness and lower our risk of succumbing to a heart attack.
A study published in the New England Journal of Medicine (NEJM) deals with this apparent paradox. Apparent because the authors of this study concluded that running a marathon (42, 195 kilometres) or a half-marathon “does not lead to an increased risk of heart attack”. According to them, this risk is, on the contrary, “low and even lower than that incurred by taking part in a triathlon or a jog”.
Mortality rate of 1 in 259,000
Dr. Aaron Baggish, of Massachusetts General Hospital, and his colleagues analysed such cases of heart attack among 10.9 million marathon runners and semi-marathoners between 2000 and 2010. Over the entire period, only 59 of these athletes suffered a cardiac arrest during and one hour after the race. Of those who suffered an attack, 42 have died resulting in a mortality rate of 1 in 259,000. This rate is 1 in 52,630 among those who take part in triathlons. The difference between the number of attacks and the number of deaths is due to the presence of medical personnel who could intervene quickly. So it is more likely to survive a heart attack during a marathon than if someone is at home.
A detailed study of these accidents and those deaths show that the majority of the victims suffered from cardiac deficiencies. In particular, the deaths were caused by hypertrophic cardiomyopathy, a condition characterised by a loss of elasticity of the heart muscle, making the heart less able to pump blood to the body. Since the age of the marathon runners have been increasing, many also suffered from atherosclerosis (deposit of plaques that reduce the blood flow to the heart). However, these problems can worsen when the person makes a violent effort, as during a marathon.
In addition to indispensable pre-deployment training, Dr. Aaron Baggish considers it essential that all candidates for this type of event first undergo a medical examination to detect possible heart failure. The risk of an individual depends on multiple factors such as high blood pressure and cholesterol, habit of smoking or family history of heart disease. In addition, it is important to ask the doctor about the risks and ways to minimise them.
Doctors’ recommendations include “no smoking one hour before and two hours after a sport” and “report to the doctor of any heart palpitation occurring during and just after exercise”. Such rules should however be obeyed by anyone who plans to do intensive aerobic exercise and is not reserved only for the marathon runners.