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| Is running a marathon healthy? |
New studies are always coming
out—some of which support my incessant ranting; others of which contradict or
refute it. Today, as I was sifting through some of the latest news via my
“news” app on Google, I came across an article written by Shots columnist Nancy Shute who suggests “marathon training
actually reduces a person’s cardiovascular risk” (1).
For those unaware, a ways back I wrote an article about the negative effects of chronic marathon
running on cardiovascular health (2).
While I could simply try to neatly and slyly murder and burry this latest
article somewhere deep in the woods, far from curious eyes, I have no desire to
have my life’s story scripted and televised for the next episode of “Murder She
Wrote: Academic Article Edition.” Instead, I plan to take an honest look at the
evidence so as to see if I might have to, in even the slightest of ways, adjust
my position on “chronic cardio.”
So What’s
the Evidence?
Firstly,
let’s take a look at the subjects of the study. The researchers examined 45
people who ran in the 2013 Boston Marathon. These subjects had actually not qualified
to run in the race, but they were permitted to run anyway because they were
doing so for a charity.
Now,
I don’t think I should have to explain some of the limitations of this study
that rear their ugly heads from the get-go. 45 test subjects is a very, very,
very, very small cross section of the number of people who ran in the Boston
Marathon. Moreover, these test subjects, as evinced by the fact that they did
not qualify to run the marathon in the first place, are not highly trained
athletes. Many of the studies which I referenced in my past article on the detriments
of chronic cardio consisted of experiments and meta-analyses conducted on, and
in reference to, well-trained athletes.
Why
does this discrepancy matter? It matters because trained athletes are the ones
most prone to overdoing things. People who run marathons on a regular basis are by far more likely to
suffer from atherosclerosis than casual one-timers (3). Those tested in this
study had only, at the most, run up to 3 marathons previous to the 2013 Boston
Marathon. In other words, we’re not dealing with professional athletes here.
I’m not saying these people are unhealthy mind you—after all, “couch potatoes”
don’t necessarily say to themselves, “I think I’m going to run a marathon today.”
Nevertheless, these 45 test subjects aren’t the sort of people who live and
breathe marathons to the extent of diehard runners.
Looking at the Numbers
Prior to and following the test subjects’ 18
weeks of training, researchers measured the participants’ markers for
cardiovascular risk. It was found that half of the participants had preexisting
risk factors going into the study; however, by the end of the study, the risk
factors of many of those at risk prior to training improved. The men who participated
in the study had their risk for coronary heart disease go down by 15% (not bad).
Additionally, average total serum cholesterol levels decreased by 5%. All in
all, things seem rather peachy.
More Evidence to Consider
In
order to further bolster the claim that marathoners do not exhibit a higher
than average risk of suffering cardiovascular related deaths, Shute further cites
a study conducted on marathoners and half-marathoners wherein the authors examined
data collected between 2000 and 2010 (4). Of all the 10.9 million runners examined (that’s
a lot of data points!), only 59 suffered cardiac arrest, with more men
being afflicted than women. In light of the data, the authors concluded that
men are at a higher risk than women for suffering cardiac arrest during a
marathon, that marathon running is “associated with a low overall risk of
cardiac arrest and sudden death,” and that (and this point is interesting to
note) the incidence rate of coronary heart disease among male marathoners
increased between 2000 and 2010.
These
are some rather interesting conclusions, of which the last is the only one that
seems at all negative. Something we should keep in mind is that, of those
competitors who suffered cardiac arrest, the highest incidence was among those
participating in full marathons. Half-marathoners exhibited less than half the
risk for suffering cardiac arrest than their marathoner counterparts. This data
makes a whole lot of sense when we consider the fact that the highest incidence
of cardiac arrest was observed during the first half of the 4th quartile
during full marathons. Half-marathoners obviously finish long before they reach
this point. But I digress…
What to Make
of This Data
I
have to admit, this evidence is hard to argue against, but my inner critic
must, regardless of what has hereto been presented, find a way to poke holes in
the data. My first, and biggest, critique of the evidence we’ve viewed thus far
is this: we’ve only taken a look at the risk of suddenly dying of cardiac
arrest while running a marathon. What about the host of other health
complications which arise as a result of “chronic cardio”?
Other Evidence
A
study conducted on 49 marathoners (42 men & 7 women) who had run 25+
marathons for consecutive years revealed that these runners had higher levels
of calcified coronary plaque than a sedentary control group (5);
therefore putting the marathoners at a higher risk for suffering stroke and dementia
(6).
One thing to pay close attention to regarding this study is the chronic nature
of marathon running involved. In contrast with the evidence Shute cites for her
article—evidence which suggest that one marathon may improve one’s risk factors
for developing cardiac disease—running consecutive marathons (25 or more!) for
several years may increase your risk
for suffering from heart related disease.
Another
study, wherein researchers tested 108 seemingly healthy male marathon runners
who were 50+ in age and had run at least 5 marathons in the previous 3 years leading
up to the study, revealed that the marathoners had higher levels of calcified
coronary plaque than controls (7). This study further
supports the conclusions of the previous one; though, notably, the test
participants in this study had run fewer marathons on average than what the
participants in the previous study had run; therefore meaning that you could very well experience negative effects from marathon running long before you’ve run
25.
Why I Think Chronic Cardio Is Bad
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| Poor soul! If only he'd read my blog.... |
While
there are numerous complicated, biological theories and explanations for why
chronically running marathons in successive fashion may harm, rather than help,
our cardiovascular fitness, I think most of these explanations boil down to one
primary theme: chronic stress. Elevated levels of cortisol and unabated
oxidative damage can have disastrous down-stream consequences for our health
and well-being. One study I looked at revealed that elevated levels of
oxidative stress following a marathon lasted up to 48 hours after the race was
completed (8). Another
study revealed that those who were ill-trained and poorly prepared for running
a marathon, experienced heart damage for up to 3 months after the
marathon was over (9).
Talk about chronic stress!
All
I have to say is: why not just say no to marathons? (at least chronically). The
occasional marathon (I’m thinking along the lines of 1 to 2 over the course of
your entire lifetime) may not be enough to cause any detrimental effects. Just
make sure that you properly train, and are well-prepared before deciding to run
one.
What to Do for Cardio Instead
Regular
moderate exercise (exercise done at 55-75% of your maximum heart rate for about
an hour a day) is associated with numerous health benefits; all of which are achievable
without having to run yourself silly. Research suggests that it can reduce your
risk of suffering from metabolic syndrome, from developing breast cancer, and
from dying of cardiac disease (10 & 11). It may
further reduce your risk of developing dementia, decrease your overall levels
of inflammation, and it might just improve your mood (12,
13,
& 14).
In
Conclusion
Look,
if you want to run a marathon, then feel free do so. Many people gain a
meaningful sense of accomplishment from finishing the 26 mile and 385 yard run.
I personally wouldn’t, but I’m not you, and you’re not me. All I ask is that
you consider your health status, first and foremost, before you set about
running a marathon, or a half-marathon for that matter. Going further, I ask that
you recognize that marathon running does not equate, 1 to 1, with health. My
overall philosophy regarding health and athletics is this: It’s easy to be healthy, but it’s hard to be an athlete. Bear that
thought in mind before you start training for a marathon for the sake of health
rather than for the sake of competition.
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| Couldn't have said it better. |
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