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Comment by kingkongreveng_ | Hacker News Reader

"He started by buying the Runner's World subscription list, which yielded about 55,000 runners to study."

People are taking this garbage seriously? Some guy surveys a bunch of hardcore yuppie runners (the kind who subscribe to runner's world) and finds the ones who continue to run a lot more haven't had heart attacks. Ya don't say. Where are the folks who usually reflexively scream about correlation/causation?

The gold standard for research into this kind of thing is the controlled intervention. You can't simply survey runners. You have to pick people and make them run. I don't think especially encouraging results have come out of this.

Everything else I've ever read says exercise is dwarfed by diet when it comes to health, and the health benefits are pretty minimal to fitness beyond a pretty low threshold. Pro athletes are not long lived.

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Almost every interesting and serious study regarding lifestyles is ethically and practically unable to be instantiated as a controlled experiment over the long term. Like many things, from studies of the economy, to social structures, to the climate. You can try to do a multivariate analysis, but ultimately you're not going to have much to go on. You have to take everything with a grain of salt, but it doesn't mean there isn't some valuable data in there. In addition, long term results are probably more interesting and important than short-term results; so much so that I would argue longitudinal studies are probably more useful than controlled studies, so long as one is careful and rigorous and vigorous with multivariate analysis after the fact.

There are many controlled intervention studies into diet and exercise. It is done. They provide the only results worth any consideration. More often than not regression analyses and "risk-adjustment" models are invalidated.

Controlled intervention over the long term, though?

>"Everything else I've ever read says exercise is dwarfed by diet when it comes to health, and the health benefits are pretty minimal to fitness beyond a pretty low threshold" <citation needed>

We've already been over this ground more than once:

According to one 32,000 person study in the American Journal of Clinical Nutrition (1999), "fit persons with any combination of smoking, elevated blood pressure, or elevated cholesterol level had lower adjusted death rates than low-fit persons with none of these characteristics". The same study found that aerobic fitness had a far more important impact on longevity than obesity did. This was cited in Fantastic Voyage, Kurzweil and Grossman, Chapter 22.

Another 100,000+ person study found that men who ran two or more marathons per year were 41 percent less likely to suffer from high blood pressure, 32 percent less likely to have high cholesterol, and 87 percent less likely to be diabetic than non-marathoners. Those who ran only one marathon every two to five years also had significantly lower risk for these conditions than non-marathoners. http://www.medicalnewstoday.com/articles/140104.php

Here's a different piece on how regular hour-long runs stimulate neurogenesis and memory improvements in middle aged humans: http://www.dana.org/news/brainwork/detail.aspx?id=7374

Distance running is one of the most beneficial things you can do for yourself. Racing marathons is also fine, with sufficient training.

The first study you link to does not appear to address the correlation/causation issue whatsoever. Specifically: "The study acknowledges that people who regularly run marathons, like many of the study's participants, may be genetically predisposed to running long distances."

The second link describing neurogenesis stimulation is more interesting due to the fact that they are tracking actual changes in the participants over the course of the study.

For the record, I do not doubt for a moment that exercise has numerous positive benefits, both physically and mentally.

http://eurheartj.oxfordjournals.org/cgi/content/full/29/15/1...

"The more marathons run, the higher the likelihood of heart disease. The number of marathons run was an independent and significant predictor of the likelihood of myocardial damage.

The runners had about the same prevalence of non-zero coronary calcium compared to age matched controls randomly assigned from a survey population."

The "quotation" you've written appears nowhere in that article you've linked to. Trying to pass that off as an excerpt from the the article is not the most ethical way to make your case.

What the article did say in the heading titled Conclusions was this:

"Regular marathon running has a beneficial effect on the cardiovascular risk factor profile but the extent of calcified coronary plaque is underestimated from that risk factor profile"

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