Monday, February 9, 2015

Will Running Kill a Regular Guy?

Don't know if you've heard, but I'm destined to die young.

If you follow even a little bit of health news, you undoubtedly saw the news last week that strenuous running is no better for you than sitting on the couch.

The Source of All the Confusion
It all comes from a study published in the Journal of the American College of Cardiology. The big takeaway from the study is that there's a U-curve. At one end, a sedentary lifestyle raises your risk of death, and then it declines commensurate with the amount and intensity of running. And then then it starts going back up as you get more hardcore. According to the study authors, if you run 7 miles per hour for 4 hours or more a week, your risk of death is pretty much the same as if you were to stay on the couch. The sweet spot, at the bottom of the U, is 1 to 2.4 hours a week of "jogging," which the authors define as no more than 5 miles per hour.

Bet Seal would make a great Regular Guy!
Now, before we start pulling this thing apart, let me be clear about one point: There is no question that moderate activity is better than no activity. If the study had simply gone that far, it'd have the Fitness for the Regular Guy Seal of Approval. Or if all those newspaper and website articles had done anything more than repeat the study's conclusions, we'd be having a totally different conversation -- or maybe no conversation at all.

But that's not what happened.

So let's have a real conversation. That's what FftRG is all about, right?

Where Does This Study Go Wrong?
The basic problem with this study is that it relies upon too small a sample size, and cannot distinguish between correlation and causality.

Don't you hate those tiny samples?
Let's start with sample size. As both Forbes and Runners World point out, 128 of 413 sedentary subjects died over the course of the study, compared with 2 of 36 high-intensity runners. Adjusting for age (the average sedentary person was 61, the average high-intensity runner 37), those numbers give you more or less the same risk of death -- or so the study says. But how can we draw any conclusions from 2 deaths? Way too small a sample size. For all we know, it would've been 2 deaths out of 400 strenuous runners.

Now let's look at the lack of causality. There's simply no way to know how these people died. Over the course of 128 deaths, you're probably going to get a pretty good cross section, so if someone got hit by a bus, it's not going to affect the overall conclusion much. If 1 of 2 strenuous runners got hit by a bus, it throws everything out of whack. The study's authors cannot demonstrate anything that shows that running had anything to do with the deaths -- and they admit this.

Sorry, But I Find It Irresponsible
First off, these latest findings are simply an update of a 2012 study, and the same problems with that one still exist now. To me, this is the biggest indictment of the study's authors, the JACC and all of the health writers and bloggers who took this latest round of findings at face value. The original study was flawed, so the smart thing to do, rather than go back to the drawing board and come up with better data, is to try to re-define it to fit the conclusion you're hoping to reach. Right?

Not for nothing, but isn't this the same basic failure of logic that has people deciding not to vaccinate their kids? Poorly done science looks legitimate, the media creates a firestorm, and people do things that are clearly less healthy.

And let's be honest: 60 minutes of weekly exercise at low-to-moderate intensity isn't getting it done.

Yes, any activity is better than no activity. But the idea that this is the sweet spot is, frankly, absurd. The average Regular Guy, running at 5 miles per hour for one hour, is probably going to burn 500 to 600 calories a week. That's somewhere between 71 and 86 calories per day, on average. Congrats! You've just worked off the half-and-half you dumped in your coffee this morning.

And that doesn't even take into account that runners who go for 40 miles or more a week, on average, have lower risks of angina and coronary heart disease. And there other health benefits from running, such as lower incidences of breast cancer, Alzheimer's and even cataracts.

Are you really going to let the deaths of 2 people tell you otherwise?

So How Much Should You Run?
As Runners World acknowledges, there is certainly a threshold at which you stop getting increased benefits from running. But that point is undoubtedly well beyond the level of just about any Regular Guy. 7 miles per hour is 8:34 per mile -- which would make you a sub-3:45 marathoner. An average of 4 hours a week at that pace adds up to 1460 miles in a year. To put that into perspective, I ran a little under 900 miles last year, and my marathon was 4:16.

As far as I'm concerned, 1460 yearly miles at an 8:34 pace is still of great benefit. I'd love to be able to get to that point some day. So I don't know about you, but this Regular Guy is going to keep running as far, as fast and as frequently as my life will allow.

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