Too much running will kill you is the gist of the Wall Street Journal piece several folks have pointed out to me this week. Ironic it is getting passed around on the week I start my training for the 2013 Boston Marathon.
The WSJ story is built around an upcoming editorial from the British journal Heart in which James O’Keefe looks at a two recent studies and draws the conclusion that while moderate (less than 25 miles a week running, slower than 8 minute pace) endurance athletics benefits longevity, activity higher than that diminishes longevity (will kill you sooner) by putting too much wear and tear on your heart. You can read the whole article here. It’s written heavily weighted toward O’Keefe’s opinion – it mentions critics of the interpretation but allows O’Keefe to dismiss them without actually presenting any of the basis for the criticism.
Alex Hutchinson, who writes the Sweat Science column for Runner’s World, has penned a response to the Journal story pointing out flaws in the theory. One is that the study that found overall runners live 19% longer than non-runners, but that of those runners, those who run more than 25 miles per week do not get this benefit, quantified the association of running and mortality after adjusting for things like “body mass index, current smoking, heavy alcohol drinking, hypertension, hypercholesterolemia,” etc. As Hutchinson points out:
What this means is that they used statistical methods to effectively “equalize” everyone’s weight, blood pressure, cholesterol, and so on. But this is absurd when you think about it. Why do we think running is good for health? In part because it plays a role in reducing weight, blood pressure, cholesterol, and so on (for more details on how this distorts the results, including evidence from other studies on how these statistical tricks hide real health benefits from much higher amounts of running, see my earlier blog entry). They’re effectively saying, “If we ignore the known health benefits of greater amounts of aerobic exercise, then greater amounts of aerobic exercise don’t have any health benefits.”
Another thing in the WSJ story that gave me pause was a quote by Dr. Kenneth Cooper, cited later in the article, suggesting, “If you are running more than 15 miles a week, you are doing it for some reason other than health.” (Then the Journal let him slip in the idea that he had a suspicion, but no evidence, that running also causes cancer. I have a suspicion that every time I drink a good quality India Pale Ale, a magical space unicorn prevents an asteroid from hitting the earth. On that basis, I will continue to consume India Pale Ales for the sake of all mankind.)
I can tell you from personal experience that running 15 miles a week may have helped my general aerobic fitness, but it had almost no weight control benefit. When I moved into the 30 mile a week range, my aerobic fitness jumped tremendously, and even more importantly, my weight dropped by about 20 pounds.
The fact that there are clearly identified health risks tied to obesity (including coronary heart disease, diabetes, and yes, cancer), suggests that an activity which could control weight, such as running more than 15 miles a week, can very certainly be done with a primary goal of health, even if other benefits (camaraderie, the fun of competition, etc.) are also derived. It further suggests in a very practical way why the flaw borne of equalizing for things like weight before analyzing longevity data (that Hutchinson points out above) is a serious one.
I run for a lot of reasons, but at the core of them is a desire to keep weight off, stay aerobically fit and control stress. I’m 42 and I’ve got four children ten and under, and I want to spend as many vigorous years with them as I can. That’s the goal.
Why then do I run marathons? Because the audacious challenge of the marathon distance, and the desire to race it with some competence, requires a programmatic and lifestyle discipline that experience tells me I would not otherwise apply to my personal fitness. In other words, time-specific, challenging and fun goals help me stay motivated to meet broader more general goals like staying fit for a lifetime.
All that said, if definitive data someday proves the risks of distance running outweigh the benefits, I’ll heed it. And I suppose for that reason I’ll continue to read these articles and try and consider them with an open mind when they get passed around.
But for now, the training goes on. I’ve 15 miler on the calendar for tomorrow if anybody wants to join me.