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Marathon running appears to ‘damage the heart’

Posted Nov 01 2010 12:51pm

While aerobic exercise such as walking, running and cycling appears not to be great for weight loss, I am enthusiastic about it for likely benefits for both body and brain. But there are limits. While exercise may be broadly healthy, more is not necessarily better. For example, practically every amateur runner I have ever met who has run a marathon (26.2 miles/42 km) has admitted to one or more ‘overuse injuries’ associated with the training for the event or running of it. One of my best friends ran his one and only marathon while still a competitive triathlete and was laid low in a persistent infection for several weeks after the run (prolonged exercise can suppress the immune system).

I am not against marathon running, but I don’t have much enthusiasm for it either. I’ve always believed the training required as well as the event itself is simply too arduous for most mere mortals. This is one reason why I’ve never run one myself, despite being a keen runner on and off until my early 30s. The thing that eventually convinced me to stop distance running was, by the way, needing to spend increasing amounts of time on the osteopaths couch having misalignments of my body seemingly induced by running manipulated out of me. This, despite wearing the ‘right’ shoes and having a pretty fluid running style.

The idea that long distance running may not be such a good idea came back to me today when I read about a study today which was presented recently at the Canadian Cardiovascular Congress.

In this study, led by Dr Eric Larose at the University of Laval, Quebec City, Canada, 20 amateur runners had their heart function assessed 6-8 weeks before running a marathon, as well as two days and then three months later. The function of the heart was assessed with MRI scanning. The participants also had their fitness assessed (VO2 max).

Two days after the marathon, there was evidence of damage to the heart muscle in the form of inflammation, swelling and ‘decreased perfusion’ (reduced blood supply) to parts of the left ventricle (the heart’s main chamber responsible for pumping blood to the body’s tissues). From the report I read, it seems that at least some of these changes were observed in at least some runners 3 months after the run too.

Perhaps not surprisingly, the fitter runners were less likely to show the signs of damage to the heart described here.

Apparently, Dr Larose was interested to know how it can be that someone who is apparently healthy enough to run a marathon can suddenly drop dead. Dr Larose’s take on this is that we should not assume there is no risk to the heart in marathon runners. He is quoted as saying “To sweep this under the rug and say, they’re marathoners, they’re good, is no okay.”

Let’s not over-interpret this: In real terms, the risk of dying from running a marathon is very small. However, what this study appears to show is that running a marathon puts significant stress and strain on the heart that can damage it, and that damage appears to last (for some people, at least) for quite a while after the event.

Part of my enthusiasm for running came as a result of reading the book ‘The Complete Book of Running’ by American amateur runner Jim Fixx. I was given the book by my parents for Christmas in 1981. I still have this book on the bookshelf in my office at home.

Jim Fixx was credited with helping to start the running boom in the 1980s. In 1984 Jim Fixx died of a heart attack, while out running. He was previously overweight and a smoker. These things may well have played a part in his demise. However, this latest evidence suggests that the distance running might have been a factor too.

I’d encourage practically anyone to take regular aerobic exercise. I don’t remember once suggesting that someone should aim their sights on a marathon. Of course there is a challenge with completing this epic distance, but the reality is being fit and healthy takes much less time and effort, and maybe better and safer for the body too.

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