Middle-Aged Male Runners at Higher Risk for Sudden Cardiac Death During Marathons

Middle-Aged Male Runners at Higher Risk for Sudden Cardiac Death During Marathons

The risk for sudden cardiac arrest during marathons is small. However, a new study indicates that the last three miles are the most dangerous, especially for males (average age of 49)Most people who survived (17/20) were treated quickly with defibrillators. The take home message: (1) Get checked by your physician before participating in a marathon. (2) Ensure that automated external defibrillators (AEDs) are readily available, especially toward the end of the race, and potential rescuers are trained in their use. [SCA Foundation commentary]

Marathons are notorious for causing cardiac problems since they put such great physical strain on the body. 

Now scientists have pinpointed who is most at risk for sudden cardiac arrest and when during the race they are most likely to fall ill.

A study presented at a American Academy of Family Physicians meeting found that men are significantly more at risk of cardiac arrest, particularly those aged 49.

And the last three miles of the race are by far the most dangerous.

The researchers, from the Crozer-Keystone Health System, a healthcare provider in Philadelphia, sent surveys to 400 marathon directors.

The marathons included in the study spanned from 1976 to 2009 and included 1.7 million runners.

While the risk of sudden cardiac arrest and death was found to be small, there was a still a ‘real risk’, said lead researcher Keven DuPrey. 

He added that because of this, every runner should have a health check-up before taking part in a marathon.

Men were particularly at risk: 93 per cent of the events occurred in male runners whose average age was 49.

The research also revealed interesting findings about when heart problems tend to strike during a race. 

Of the 30 sudden cardiac arrests reported, three-quarters occurred after the 15th mile. And more than half of the events took place between mile 23 and the finish line.

Twenty victims survived – 17 of whom had received treatment from a defibrillator. Many of these people were found to have underlying heart rhythm problems. 

The figures led to the study authors suggesting that a defibrillator – life-saving machine that gives the heart an electric shock in some cases of cardiac arrest – be placed at the end of every race.

The researchers said more defibrillators should be placed along the last few miles of the marathon route, as this is when a cardiac arrest is most likely to occur.

‘There is no set protocol on where and how many should be placed in a marathon,’ Dr DuPrey told the website MedPage Today.

‘Every marathon medical director has the discretion to place them at various medical stations along the race course. But from our study, we found that most of the cardiac events happen in the last four miles. So that is where the focus should be,’ he said.

He noted that the overall risk of sudden cardiac arrest during a marathon is low, but with no intervention, the risk of death is greater than 95 per cent. 

For every minute that passes without defibrillation, survival drops by up to 10 per cent.

The risk of sudden cardiac arrest was one in 57,000, while the risk of sudden cardiac death was one in 171,000.

Coronary artery disease was the cause of death in the majority of men. Dr DuPrey suggested that an ‘underlying electrolyte abnormality’ may also have  predisposed these runners to having a cardiac arrest. 

Electrolytes are substances found in the blood, such as sodium, potassium, chloride and bicarbonate. They affect the amount of water in the body, the acidity of the blood (pH), muscle function, and other important processes. They are lost thorough sweating and must be replaced by drinking fluids.

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