I go running when I have to. When the ice cream truck is doing sixty.
– Wendy Liebman
We spend a fair amount of time on this blog looking at the illogicality of bad science. Let’s practice again today, shall we?
I have here a great little article about running:
According to a study of 1,098 runners, those who ran twice or three times a week at a speed of 7mph were more likely to die prematurely within the 12 years of the study, compared to those who run at 5mph, and they were also more likely to die than those who didn’t do any exercise at all…
…The study showed a significant lower mortality rate among slow joggers that were young and healthy.
My main concern to this point in the article is that they should have clarified this was only an observational study. They looked at mortality rates and compared them to people’s reported activity levels. They did not actually conduct a study. Also, it would have been more accurate had the writer clarified that what they found through reviewing old data was an association. No one has even begun the hard process of proving any kind of causation. This study is just a first step, and a very basic first step at that.
If this was proper science, what would the next step be? We would base a theory off of our association and then go about trying to test it. To test it, we’d have to eliminate confounding factors and find a way to prove that of all the things that make this person
very different from this person:
the one thing that makes the runner more likely to die early (or live longer; whatever our theory is) is the running.
Just to remind us: that did not happen in the “study” we’re reading about.
Here’s what “experts” got from this “study.”
“When performed for decades, this activity level could pose health risks, especially to the cardiovascular system. If your goal is to decrease risk of death and improve life expectancy, jogging a few times a week at a moderate pace is a good strategy. Anything more is not just unnecessary, it may be harmful,” he (Peter Schnohr, a researcher for the Copenhagen City Heart Study at Frederiksberg Hospital) said.
Quick class: what’s wrong with this conclusion? I mean other than the ridiculously inane statement: “if your goal is to decrease risk of death and improve life expectancy.”
(No, Peter, actually I was hoping to decrease my risk of death by lowering my life expectancy. This is America. We can have whatever we dream!)
There are numerous things wrong with this statement, and hopefully you were able to see them. The biggest one is simply this: this observation of an association cannot be used to draw such conclusions. You might be surprised to find me saying this, knowing as you do how I feel about excessive exercise. But I, like Batman, combat crime wherever I see it, and this article is good practice in learning not to be fooled by slipshod “science” when it is used in an entirely unscientific way to support conclusions it simply cannot bear. Peter would be perfectly justified in restating what he said as a possible hypothesis that bears further testing. He is completely unjustified in telling you to modify your behavior long-term based on an unproven assumption rife with confounding factors.
Maybe running too hard is bad for you. I think it is, frankly, and not because of associations. I won’t go into all that now. The point is, though, that this woman doesn’t know how to think:
Maureen Talbot, Senior Cardiac Nurse at the British Heart Foundation, said: “This study shows that you don’t have to run marathons to keep your heart healthy.
“Light and moderate jogging was found to be more beneficial than being inactive or undertaking strenuous jogging, possibly adding years to your life.
No, Maureen. That’s not at all what “this study shows.” There’s only one thing this study shows: researchers have found a preliminary association between the time and effort spent exercising and the lifespans of people who tend to do that, such that it might be worth further testing to explore the unproven hypothesis that being moderately active is better than both inactivity and excessive activity, and that even inactivity is better than excessive activity.
But what other possible conclusion could we come to?! Maureen might cry. We all do this all the time. We see something, and we draw a conclusion. We like to remember the times we were right; but how many times were we wrong? We love our ad hoc fallacies and our over-generalizations.
Maureen already believes that being inactive is “unhealthy.” Thus what she sees and how she reacts is colored by prejudice. You can see this not only in her improper conclusion about what the study “shows,” but–far more clearly–in her emphasis. Rather than fixate on the excessive runners–who were actually the main focus of the study–and implore them to give up hurting their bodies, she instead fixates on the inactive group and ignores the excessive runners completely.
Digging a bit deeper, we find another article on the subject:
Researchers registered 28 deaths among joggers and 128 among sedentary non-joggers. In general, the joggers were younger, had lower blood pressure and body mass index, and had a lower prevalence of smoking and diabetes.
You simply cannot take two groups of people, one of which is younger, more active, thinner, less likely to smoke, non-diabetic, and has lower blood pressure; while the other is made up of an older population of fatter smokers who are a more likely diabetic and less active, and then say it is definitely the activity levels that makes the difference. Older people aren’t as active as younger people, and guess what: older people die more often younger people!
What revelations modern science reveals.
What if people are laying on the couch because they’re sick, not becoming sick because they’re laying on the couch, Maureen? What if they don’t feel like running because they’re always tired, the way diabetics often are? What if the excessive runners aren’t dying more because they’re running too much? What if they’re running too much because they’re dying?
Let’s just give an example of another possible explanation for these outcomes. My hypothesis is no more valid than that of the researchers; but it is no less so, either. That’s the point. We don’t know what’s going on here.
Here we go, then:
When someone overeats glucose, that excessive glucose has to go somewhere so it doesn’t kill the eater with high blood sugar. The two most common genetic responses are to either get fat (the glucose goes shunted off safely into fat cells, and particularly those in the stomach) or to stay thin and be impelled to activity (the glucose gets shoved off safely into the muscles to get burned). All of the proceeding are facts.
What if we apply these facts to what we see and assume that one group is one end of the genetic spectrum, impelled by physiology and metabolism to sit down, while the other group is the other end, impelled in the same way to move around? The people in the middle would represent those who either are not eating excessive amounts of glucose, or who are genetically able to tolerate larger amounts of glucose than most people.
I don’t know. I’m just saying there’s more than one way to look at this data, and there’s no way anyone should be drawing such wide conclusions from it.
Try it yourself! Go find a report from any “health” section of any website and I bet you can find this kind of lazy conclusion jumping. Learn how to recognize it and you’ll go a long way towards taking control of your own health. Practice makes perfect.
Plato says he’s hungry
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