But on Monday, the day after we ran the Kalundborg Winter Marathon, I found myself unable to think straight. Patients and colleagues alike would ask me questions or give me information and I would stare at them as if they were a teacher from Charlie Brown. Normally I would attribute behaviour like this to low blood sugar or lack of sleep. But I am certain neither of these were the case. And my boss said I looked ill and that she was concened about me. Despite being a physician, I find myself unable to explain these untoward effects other than attributing it all to "exhaustion".
Here I am looking kind of dead after the race:
To determine whether or not a marathon is "healthy", one should probably consider the immediate, secondary and long-term effects it has on the body.
1. Short-term health effects:
It is hard to find many short-term health benefits. There is of course that rush of adrenaline and another benefit for most people is burning calories. Negative effects on health include muskuloskeletal injuries, hyponatremia (from drinking too much water), heat stroke, kidney failure (seen rarely in ultras) and the extremely rare but feared sudden cardiac death. In looking at studies of people who die from heart problems in a marathon, these are exclusively people with underlying heart conditions, whether they know it or not. There is also damage and death of cardiac muscle cells during a marathon, shown in multiple studies by a rise in troponin in the blood after a marathon, as one sees with a heart attack. I'll get back to the meaning of that long-term in a bit.
A great study in the British Medical Journal (BMJ. 2007 Dec 22;335(7633):1275-7.) looked at large marathons in cities all around the world and found that one is more likely to die of an accident in the city outside of the race than to die during the race. I think that helps put the issue of marathon safety in perspective. And one of the best things about marathons may be that they result in so many road closures, that numerous traffic-related deaths are prevented.
I have also never come across serious problems pregnant women have had while running marathons. But you can bet your life savings that when the first pregnant woman does make the news for a marathon-related health problem, pregnant women all over the world will decide not to run at all when pregnant.
2. Secondary effects:
Not only does one feel tired, but there is quite a bit of evidence that one's immunesystem functions abnormally for up to 72 hours after a race.
2. Long-term health effects of a marathon:
First of all, it is extremely hard to do good research on the long-term health effects of a marathon, when marathon runners tend to be healthier people in the first place.
But, I did come across one interesting study in a literature search:
It appears that prevalence of hypertension, hypercholesterolemia, and diabetes decreases with the frequency of marathon participation independent of annual running distance (Med Sci Sports Exerc. 2009 Mar;41(3):523-9).
As far the long-term effects on the heart, no concensus has been reached. All studies are small and they have found conflicting results (read this article in the New York Times for more info http://well.blogs.nytimes.com/2009/09/30/phys-ed-how-do-marathons-affect-your-heart/).
Anyone else have thoughts on the subject?
Here are so more pictures from Kalundborg Winter Marathon and a video clip of the marathon from Danish tv:
First the link to the video:
And some pics from Tor Rønnow (minus the naked ladies, thanks, Tor!):
Running Song of the Day: All through the night by Cindi Lauper