Ask the Doctor: ‘Can marathon running lead to an increased risk of cardiac arrest?’

“My husband has just started training for his first marathon. He has never been into running but this was one of his goals for 2024. I have been reading that doing a marathon is bad for your heart and can lead to an increased chance of having a cardiac arrest as it puts so much stress on the heart. Is this true and if so, should my husband be getting his heart checked before throwing himself into this challenge?”

Answer from Associate Professor Dermot McCaffrey, Consultant Cardiologist Beacon Hospital

A great question regarding the risks related to your husband’s goal of running a marathon. As this would be his first marathon and he “has never been into running” there is an understandable concern regarding how it may impact his health.

Signing up for a marathon is a challenging goal and should really be considered by someone who has done quite a bit of light running. Your husband should enter a few shorter runs, i.e. some 5 or 10km runs, building up to a 10 mile and then half-marathons before signing up for the full thing! After trying these shorter distances, he will know if he is “in to running” or not. He can then decide if a full marathon is not only a realistic but also a safe goal.

You read that doing a marathon is “bad for your heart and can lead to increased chances of having a cardiac arrest.” This information is correct but is nuanced. Marathon running can increase your risk of cardiac arrest in the short term, especially for middle aged male runners. However, the training and lifestyle changes involved lowers one’s overall likelihood of cardiac arrest and other heart problems.

Nevertheless, because of the increased risk while running 26 miles, competitors often must sign a waiver or obtain medical clearance before being allowed to enter marathon events.

My advice would be that your husband attend his local GP for a general health assessment. His GP will check his family history, ask about smoking and alcohol use, check his blood pressure, his weight and possibly arrange routine bloods.

If any concerns were raised after that visit, his GP might refer him for a full cardiac assessment such as that offered in the Beacon hospital through the Rapid Access Cardiac Clinic or through his local cardiology department; this further evaluation would determine his cardiac risk and arrange further testing if indicated. Such a thorough cardiac review would put both you and your husband’s minds at rest considering the challenge he is taking on.

Assuming he is passed as being “fit and well”, then my final advice would be that he choose a marathon some months away, e.g. the Dublin City Marathon in October. This would allow him sufficient time to build up his exercise tolerance, reduce the risk of musculoskeletal injuries and optimise the chance that he finishes his first marathon both safe and sound and at the time he is hoping to achieve.

Hopefully he will find that he is “into running” and will enjoy the physical and mental health benefits associated with long distance running.

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