Is Running ‘Too Much’ Worse For You Than Not Running at All?

© Martinmark |

© Martinmark |

Runners run for all kinds of reasons: To be outdoors, to compete, to get that runner’s high, and just to have fun. But when it comes to running for health, is there such a thing as running too much?

According to one study, published this month in the Journal of the American College of Cardiology, that just might be the case.

Using data from the Copenhagen City Heart Study, which initially sampled nearly 20,000 people living in Copenhagen in 1976, the researchers compared death rates among groups of people with different running habits.

They examined nearly 4,000 healthy non-joggers and about 1,000 healthy joggers, who were classified as either light, moderate, or strenuous runners.

They found that running even once per week significantly reduced the risk of death, which isn’t too surprising, given mounting evidence that a sedentary lifestyle is ultimately a deadly one.

Heavy, strenuous running = dangerous?

But they also found that runners in the strenuous category had higher mortality rates than moderate and light runners - just as high as the group who didn’t run at all.

But don’t give up your marathon dreams just yet.

“I believe that the paper is quite strong to show show that all one needs to do is a low amount of running to achieve maximal health,” says Dr. Carl “Chip” Lavie, director of exercise laboratories at the John Ochsner Heart and Vascular Institute in New Orleans.

“But I think that their paper was rather statistically weak to suggest harm or even loss of benefit from higher running,” he added.

Lavie, along with two other researchers, published a commentary along with the research paper, documenting some of its significant limitations.

The vast majority of the non-joggers, for example, regularly participated in some other kind of physical activity and had to be excluded from any analysis on the link between jogging and rates of death. The non-joggers were also, on average, 20 years older and had higher rates of obesity, diabetes, and high blood pressure.

Though the authors controlled for these factors, the editorial notes, it’s impossible to entirely eliminate the bias that they create.

“I am surprised that it was not published in a less competitive journal as opposed to such a competitive one as JACC” because of these weaknesses, says Lavie.

So what can we take away from the paper? Its strongest point is adding more evidence to the conclusion that even a minimal amount of exercise is better than nothing.

Even a little running goes a looooong way

A massive 2011 study, for example, followed 416,000 people in Taiwan for an average of eight years, finding that exercising 15 minutes a day, or 90 minutes a week, was enough to add three years to life expectancy — and that each additional 15 minutes daily reduced risk of death by a further 4 percent.

Another study, published last August, found that running even five to 10 minutes a day, or 50 minutes a week, added significant health benefits.

Where the science is a bit murkier is on heavy running - how much more running helps, and whether it can potentially hurt.

Some studies have shown that high-intensity aerobic exercise may increase the likelihood of heart problems, particularly in people who already have heart disease. But there’s not yet enough evidence to make conclusions.

“If people are exercising , and especially running, for health reasons, they only need to do a little for maximal health benefits,” says Lavie.

“If they want to run more, they are doing so for non-health reasons - fun, competition, ego. If they are running very high amounts, there are risks, but the risks are probably overall small.”

Laura Dattaro is a New York-based science journalist, writer and producer. She’s also written posts for us including “What Running Your First Half Marathon Really Feels Like.”

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