Is Marathon Running Bad For Your Heart?

Whenever I get an enquiry from someone looking for a personal trainer in London to help them train for a marathon, I refer them to a personal trainer who specialises in long distance running. It’s definitely not my thing. I’m happy to run 10K, but I’ve never had the slightest desire to run any further than that. Never will! If you’re looking for a personal trainer to train with you for a 5K or 10K, I’m happy to do that, but marathons, no.

marathon running in London

Article in The Independent, 29th November 2012

The headline read “Marathon running is bad for you, and it’s best to keep exercise to a maximum of 50 minutes a day, say doctors”.

This was from an editorial in the journal Heart, written by Dr James O’Keefe, head of preventive cardiology at St Luke’s Mid America Heart Institute. He based his findings on 2 large studies on runners’ life expectancy.

One study followed 52,600 people for up to 3 decades, including runners (not all of them marathon runners) and non-runners. The runners as a group had 19% lower risk of mortality than the non-running group. But those who ran marathons regularly had the same risk factors as sedentary people. His advice: exercise for no more than 1 hour a day.

For those who run marathons regularly, he said “You end up stretching the heart and tearing muscle fibres. Up to 30% of those who finish marathons have elevated troponin levels, which is a marker for heart damage. That’s the marker we look for to see if someone’s having a heart attack – it’s irrefutable evidence of heart damage.”

He went on to say: “If you really want to do a marathon or full distance triathlon, it may be best to do just one or a few and then proceed to safer and healthier exercise patterns. Running too far and for too many years may speed one’s progress towards the finishing line of life.”

Readers’ responses to this article in The Independent

This article provoked a huge response. Most were pro-marathons, for a variety of reasons. It’s for charity, said some. If your body is built for it, you’ll suffer no ill-effects, as long as you train sensibly in the months before the event, said another. The advice is OK if you want a mediocre life, said another pro-marathon comment, but what about elite athletes and sports people, are you going to say it’s bad for them, give it up? Others pointed to the sense of satisfaction and achievement.

The anti-multiple marathon comments included “endurance  athletes look so unhealthy”, and another said it’s worth knowing the risks in advance and weighing it up against the reasons why you’re doing a marathon.

I’ve yet to find the details of the studies Dr O’Keefe is relying on, but it would be interesting to see if the participants in the studies went through a heart-screening at the start of the study period, to see if any had pre-existing heart problems. Otherwise it could be the case that the marathon runners who had heart attacks, may have had pre-existing genetic heart problems which the marathon running exacerbated, rather than the marathon running being the sole cause of the heart attacks.

A better study would be one which only included participants with no pre-existing heart problems, so that the variable being tested (multiple marathon running) could be tested without other variables (pre-existing heart condition) confusing the results, and leading to less reliable conclusions.

Article in the New York Times (23rd May 2012)

The headline in this article was: “Is marathon running bad for you?”.

Journalist Gretchen Reynolds looked at a study published in the American Journal of Sports Medicine, which examined deaths of marathon runners (during the race or within 24 hours following the race) of every known marathon in the USA between 2000-2009.

The study found that 28 people died in total, mainly from heart attacks, some from hyponatremia, which is where excessive water consumption and excessive sweating disturbs electrolyte levels to a dangerous degree. This death rate was approximately one in 100,000 marathon runners. The conclusion: “the science suggests that overall distance running are extremely unlikely to kill you”

Dr Julius Cuong Pham, associate professor of Emergency Medicine, Johns Hopkins University School of Medicine, added that marathon running probably prevented many heart attacks among people who might otherwise have led sedentary unhealthy lifestyles.

Study in the New England Journal of Medicine (published 12th January 2012)

This was an even larger study, of 10.9 million runners (marathons and half-marathons) between 2000-2010, and looked at both fatal and non-fatal cardiac arrests. The study found 59 cardiac arrests (of which 51 were men) of which 42 were fatal. This equates to just 1 death per 259,000 runners, around half the cardiac death rate of the general population.

Dr Thompson, chief of cardiology at Hartford Hospital in Connecticut, one of the authors of the study, concluded that overall, running lowers your risk of coronary heart disease, but doesn’t inoculate you against heart disease, as other factors like genetics, viruses, and other lifestyle factors play a part.

Comparing marathons to half marathons, he said that heart attack risk was significantly higher among the marathon runners, and the highest risk group of all was male marathon runners.

A healthy heart is tougher than you think

In an interview with Medpage Today, Dr Stephen Gielen of the University of Leipzig, and spokesman for the European Society of Cardiology, said this:

“In evolution, we were selected out as hunter-gatherers where we would run and hunt miles from home to find enough food for the day. It is astonishing the enormous exercise that the human heart can endure.”

He went on to advise, however, that anyone over 40 should get a heart-screening before taking up marathon running.

Canadian Cardiovascular Congress, Montreal, 2010

Dr Eric Larose of the Quebec Foundation for Health Research,  presented a study of 20 ‘low risk group’ marathon runners, whose hearts were examined before and after a marathon. He concluded:

“There is no permanent damage to the heart, but there is some temporary reversible damage that occurs during the run”

So after reading all these studies, if you still want a personal trainer to help you prepare for a marathon, I’ll happily put you in touch with some marathon experts in London.  Meanwhile, please leave a comment below. Have you run a marathon or even several? Are you thinking of running a marathon? Share your views!