Deaths during running: Is exercise safe, Part 2

Running and safety continued - some comparisons, and the key point to the debate

One of the best things about this site is that often it is a source of information for me as much as I hope it is for you! And in response to last week's post about the safety of running, we've had some great comments and more information, which warranted a follow up. Also, I felt I should re-emphasize the purpose of that post, which was really a call to the media to change the view they project of running.

And most importantly, it was a message to runners out there to help them 'filter' out what is basically over-hyped reporting about deaths during running, akin to the "shark attack" phenomenon, where sensational reporting skews our beliefs over the relative safety of an activity (surfing in that case, running in ours). Perception does not necessarily equal reality, in other words, and the post was a call to question very hard what the risk of running is. If you do, you'll find that it's not nearly as high as is sometimes portrayed!

And now we have some points of comparison, thanks to you readers!

Host a marathon every weekend

First off, a study last year from the British Medical Journal took a rather creative (Malcolm Gladwell-esque) look at marathon safety. Canadian researchers compared the risk of dying in a motor vehicle accident with that of sudden cardiac death during marathon participation. Because courses are closed to traffic for larger races, it's possible to ask how many motor accident deaths would have been prevented as a result of the race, and compare this to actual deaths (thanks to Bengt, Tony and Amby for raising this one! As an aside, the author Redelmeier seems to be an expert on driving fatalities - another 2008 study published in JAMA is called "Driving fatalities on US presidential election days")

The diagram below summarizes the main finding:

So basically, the study found that the closure of roads for the major marathons prevented an estimated 46 deaths as a result of motor vehicle accidents. However, 26 sudden cardiac deaths were reported during those races (based on newspaper reports, it must be pointed out, and thus potentially a slight under-estimate). The relative risk - 35% lower when marathons happened.

And a final really important point - the authors have controlled for the accidents simply be relocated to other areas, and so marathon closures do not simply shift the site of the accidents. If you want the paper to check out their solid stats, please just let me know, as usual.

The author's conclusion is shown in italics above, but it was that "Organised marathons are not associated with an increase in sudden deaths from a societal perspective, contrary to anecdotal impressions fostered by news media."

Some numbers

Interesting that they picked up on the "impressions fostered by news media", which is basically the point of these last two posts. Interesting also that in 14 million hours, there were 26 deaths, which amounts to approximately 1 per 540,000 hours, a figure which agrees with that which our friend Amby Burfoot put forward in his comment to our last post. For a similar analysis, check out Amby's report on marathon deaths written last year, which is far more comprehensive than I've had time to do here - it's a big read, but if you're up for more details after this article, check it out.

This figure of 1 per ± 500,000 hours is also about the same as a (very) crude calculation would provide based on the information that about 6 deaths occur every year in the USA, and that about 3 million hours of running go into those deaths (this was all covered in the last post, if you want to read the numbers more).

My point, however, not covered by this study or the latest reports, is that marathon running hours are not limited to the hours of participation. There is substantially more time spent running in training, and by those who run but don't participate. If you factor all these people in, do the numbers change? Without quantifying training times, it may remain an unanswerable question.

These people, and their training, are the most important component of the debate, because they are most likely to be dissuaded from running as a result of the negative portrayal of running. Yet they are clearly, based on a large body of research by the likes of Paffenbarger (again, see the previous post), more protected than the sedentary population, and so should be hearing affirmation, not condemnation or warning for their choice to run. And if running in events that may have a risk of 1 death per 500,000 hours is the goal, then it too should be encouraged.

Comparing running with some other activities

To compare running a little better, have a look at the comments to the previous post, where you'll see some stats about how many deaths are caused by other activities. Smoking, for example, claims over 300,000 each year. Flu, 15,000, and car accidents, 20,000. Of course, the problem here is that these numbers don't indicate the 'exposure', or how many people spend how much time doing the activity. Smoking may simply be high because many people smoke, whereas 6 sudden deaths during running may be because hardly anyone runs.

Risk and exposure

So, for another comparison, I received data from a reader who had put together some stats on deaths per million hours of the activity. That piece can be read here, and the original article is here.

Admittedly, it's a little uncertain where this data were sourced, and in this field of epidemiology, that is crucially important. So with a proviso that the data is not "gospel", here is the summary list:


Deaths per million hours:

Skydiving - 128.71
General Flying - 15.58
Motorcycling - 8.80
Scuba Diving - 1.98
Swimming (presumably competitive) - 1.07
Snowmobiling - 0.88
Motoring - 0.47
Water skiing - 0.28
Bicycling - 0.26
Airline Flying 0.15
Hunting 0.08


Running? Depending on which number you believe, the risk during marathons is between 1.8 and 2 deaths per million hours, so it's around the same as scuba diving.


One problem - that doesn't factor in the health benefits, which I emphasized previously. Regular physical activity reduces the risk of cardiac disease and a host of other health problems, and so the risk is moderated by the benefit.

Most important of all - applying this dizzying collection of numbers to yourself

To end off (before we tackle some more enjoyable topics like coaching and science in the coming days), a word on applying this to you. I know I've thrown figures and numbers at you, and your head is probably spinning, so let's try to simplify this.

The reality, at the risk of sounding callous, is that people do die during running. A big race, with 30,000 runners, seems likely to experience such an event every 3 to 4 years. Put differently, between the six major marathons each year, there would be a sudden cardiac death each year.

People who are predisposed to cardiac death are more likely to die while running than while sitting on their couch. This is undeniable. But equally, people who run, including those who run marathons, derive enormous benefit from it - their health gains as a result of running are sufficient to over-ride habits like smoking in terms of overall risk of mortality (Paffenbarger, et al).

You can investigate whether you might be one of those predisposed, higher-risk people, but the problem, as we've discussed at length before, is that medical testing cannot currently identify all the people at risk. Some, certainly, and so medical screening, particularly if you are concerned, would be advisable.


Even in the absence of such 'confirmation', however, you still have a choice. With the risk at one death per 500,000 hours of running, and with the knowledge that running can improve your health, your choice is to remain sedentary and avoid that 0.8 in 100,000 runner chance, or you can run and benefit from the numerous positive adaptations you'll experience. It is a risk-management matrix, where running and remaining sedentary must be weighed against one another, benefits and risks understood, and a choice made. Your ability to manage the risks, by undergoing tests, by training and by adopting a healthy lifestyle, makes this choice far simpler than leaving it to guess-work.


And finally, for the media, physical activity should be encouraged, not 'demonized' with threats of death caused by activities like running. Sensational sells, but when it deters people from running, it becomes a problem. So some perspective, some affirmation and positive reporting would go a long way to fixing what is a growing problem of inactivity and obesity, subtly being driven by the media reporting. By all means, educate and inform people of how to maximize benefits, but let's not give a voice to those who view exercise as radical from the safety of their couches.

Ross

P.S. As mentioned, a series on coaching and the application of science starts tomorrow. Join us then!

Further reading:

Amby Burfoot, Editor-in-Chief of Runners World has done a comprehensive piece on safety of marathon running. I've tried to make this article (and the one before) more philosophical and directed at the media coverage, whereas his is full of information and 'hard facts'. But this is a great piece, and if you're up for more reading, this is a great read:

Amby Burfoot: SPECIAL REPORT: ARE MARATHONS DANGEROUS?