No, More Running Probably Isn’t Bad for You

Why didn't the original NYT piece by Reynolds not focus on the statistical flaws of this study? That was the only story here.

I'll answer my own question. Reynolds keeps writing this same story, based on the same weak evidence. She apparently has decided it is true for whatever reason that excessive running is bad--no doubt at some point for every individual this is true, but this study does nothing to establish where that line lies-- it no doubt depends both on the individual and on that person's current level of fitness. If I pushed myself to try to run as fast as I could fifteen years ago I'd fall apart.

Data results are reported almost weekly and change about that often.

Simple solution: follow your own path based on how ypu feel. Do at most, a little out of your comfort zone, always giving yourself, (not a report), the benefit of any doubt.

The purpose of exercise in the modern era is to provide sufficient physical activity to compensate for the fact that most people get little or no daily physical activity. Manual labor and walking in a work environment is confined to select trades. The white collar crowd sit and snack a lot. Simple rule, don't become compulsive about strenuous exercise, fatigue testing your joints tendons and muscles will damage them eventually. In the end luck and your genes will determine how long you will live and what your quality of life will be.

Thanks Justin!!

I care more about quality of life than quantity of life. Who wants to live to 100 years, if that means taking 10 different medications or being homebound by the age of 60? Even if running did shorten my life span, it would provide more active years compared to being sedentary.

This is a wonderful article. Far too many fitness studies produce findings that are based on dubious study designs and flimsy statistics -- or at least, when study authors know this and state their findings with due caution, fitness reporters then come along and misrepresents what the studies show.

NYTimes readers would benefit if Mr. Wolfers were to fact check the reporting on fitness studies in its own pages on Well blogs, for they are guilty of much of the same kinds of hasty conclusion fallacies that Wolfers identifies here: underpowered studies, flimsy measurement techniques for what counts as healthy, failure to account for obvious confounding factors, not controlling for reverse causation, selection bias, etc. Too much of what is passed off as sound science in these pages actually fits the bill. And that needs to change.

the study is probably telling people, there is more to life than running 2 hours a day , 7 days a week... as William Shatner told Trekkies some 30 years ago- "Get a life".

I'm always interested in any clinical study on exercise. Especially on running, which I've been doing for over 45 years. Glad to see that on close inspection this original study indicating harm from "running too much" turns out to be deeply flawed. My running had gotten shorter and slower as I approached 65, but now that I'm retired I've committed to a half marathon- something I haven't done in decades. The increase in mileage is comfortable, even thrilling, and my recent cholesterol numbers and all of that have never been better. My knees and lower back? Not a twinge, thanks to a couple of yoga classes a week.

Finally a sane voice parsing the actual data!

When the Copenhagen "Dose of Jogging" study was first reported on, here and elsewhere, I went looking for the original study. But I had to settle for just the abstract, as I couldn't get at the full study without paying big bucks. (Lesson #1.) A quick reading of the abstract alone sufficed to convince me that the study's conclusions were likely flawed, and the mass-media reportage of it, even more so. (1) The two deaths in the "high-intensity" jogging group was obiously too low a numerator to enable the "death rate" [sic] to have statsitical signficance. (2) The elevated death rate claimed for the medium-intensity jogging group was not reflected in the abstract's numbers. (3) A likely source of introduced bias was revealed in the design summary. The "comparison" group [sic] -- non-runners --was, like the study group -- runners of varying intensities --culled to include only "healthy" individuals. If, in fact, regular physical activity does impart health advantages -- a reasonable hypothesis -- the authors, by exlcuding all unhealthy individuals, even though they did so for both non-runners and runners, likely introduced bias, since they likely "leveled" the two groups more so than would be the case if they simply randomly selected healthy and unhealthy individuals from both groups for the study.

Most folks are simply not scientifically literate enough to discern what's wrong with or right with a study such as this.

A big unknown in all these studies is the reason why people bother to exercise. Jogging 4 or 5 times a week is inconvenient and painful (check out the number of articles in Runner's World on injuries). In my experience, most men who exercise hard and compulsively have been given a scare. Either they have a bad family history of heart disease or diabetes, or their doctor has told them they are at risk for some other reason such as high blood pressure. It could be that the most compulsive exercisers (high intensity group) are not a random sampling of the population, but a group that starts out less healthy. Maybe that helps to explain the U-shaped curve found in other studies, correlating exercise intensity to longevity.

The "more running isn't better" theme is not a new one: here's a study published in 2012:

http://www.escardio.org/about/press/press-releases/pr-12/Pages/regular-j...

Same conclusion.

Look at the first table in the journal article cited : out of 394 non-joggers, 120 died (30%) during the test period, while 7 out of 570 (1.2%) of the slow joggers died. That's the real story: there is a HUGE difference in jogging versus not jogging in terms of all-cause death, even if you jog "slowly".

Thank god, I thought I was the only one who was finding this study to be contrary to common sense. Many speculate that in addition to intellect, our long-distance running capabilities are among our most valuable evolutionary traits. This by itself would contradict this study, indeed, it seems ridiculous to conclude that "strenuous" running is bad. In the past "strenuous" running was probably common, if not necessary to hunting and survival.

Glad to see someone explain why this study has little statistical backing and reinforce common sense and historical context.

I gave up running years ago for squats and walks, mid wight lifting (curling bar or dumbbells), an occasional bicycle ride to the store, backpacking and recreational motorcycle rides to interesting out of the way places. Not short but not a particularly long legged person, swam middle and long distance in college and ran 6 miles/3 x wk til age 35. I think running is good for some people but at my age with shin splints it is probably wise to not promote deep bruising, irritation or inflammation of fascia in the lower extremities. Listen to your body, it knows best.

When i first read about this study i was reminded of an Onion article " Eggs Good For You This week," and that's about how serious i considered the new report.

The flaw is not in the scientific method but in the assumptions, not based on facts of a large, statistically meaningful sample. Furthermore, the author(s) clearly engages in speculation with regard to conclusions, which fail to account for possible causation of mortality by illness or even accidental death. No doubt, the evidence shows false conclusions. I am not saying "falsified", however the adage " Publish or perish" certainly cast a cloud over the motives, underlying a study that, in fact, recommends less exercise rather than a healthy life style.

It's great to see a thoughtful article about how solid certain findings are. Ideally, this kind of analysis would accompany every article that reports medical findings so readers get a sense of how believable a finding is.

That said, it is a thin edge: not to say all science is garbage on the one hand, and yet to acknowledge when a finding is weak, on the other.

There are worse things than death . . .
Such as a massive stroke related to diabetes, high blood pressure or obesity. The claim is silly. There are more fire trucks present when there is significantly more fire damage. This does not mean fire trucks cause fire damage. Worse, the correlation in this claim is very weak to begin with, let alone indicative of a causal relationship. I bring my own bias: In 2011 I was 100 pounds overweight. In 2012 I lost it and ran my first 100K. In 2013 I ran my first non-mountain 100 miler. In 2014 I ran my first mountain 100 miler (over 16,000 feet of elevation gain). On September 11 of 2015 I will be running the Tahoe 200 mile Endurance Run. I'm here to tell you that I'd rather die sooner than go back to being trapped on the couch by my fork.

I am a RN who for decades has read the peer review literature. For the most part it is trash. It is incompetent and corrupt and is best taken with a grain of salt. The authors are frequently wrong but never in doubt.

This is a very dangerous article and Mr. Wolfers is very fortunate that it was published. The danger is that it encourages independent thought rather than blind credibility of published scientific data. As a medical professional, I have been trained to rely on evidence-based data, which emphasises that science is better than random belief, even though the quality of that evidence may be compromised. The notion that published research might need to be scrutinized before being accepted creates the potential for having to interpret medical information from a nuanced perspective. I'm not sure we are ready for this in our culture. If we had to evaluate scientific data for its accuracy, we'd have to questions certain axioms that make our lives so much easier, such as the notions that the drugs our doctors prescribe are safe, and that vaccinations are an unqualified good for society. Are people really ready to challenge the authoriity of the medical and research establishments. Current trends suggest not. It is so much more convenient to believe the falsehoods that make us feel safe rather than embrace the complexity and uncertainty of the world as it really is.

Good article. Three questions:

1. What kind of researchers are so poorly trained that they publish such profoundly unsubstantiated results? How frequently are researchers this poor?

2. What kind of journal is so hard-up for articles that it publishes such rubbish? What proportion of journals have such low standards of quality?

3. What kind of science/health reporter mis-informs readers by writing such nonsense and what sort of editor allows such nonsense to make it past his pen? How does reader determine which articles are well-founded and which are rubbish?

Great article and counterpoint to a flawed study. Do I run? yes. Competitively? Off and on, I have. Have I worried about the possible health implications of hard and/or long endurance activities on my heart, to the point of curtailing them? yes. I like to believe that I keep an open mind, and am willing to change my behavior and forgo and activity that I dearly enjoy.

But I believe all the science is far from conclusive. Also, I suspect that the greatest risk of excessive cardio activity is to the heart, and for a subset of the population. On the other hand, I feel that being in better than average shape, in no small part due to training competitively, likely reaps health benefits.

Only as of 7 months ago I got back into racing after a quite lengthy repreive. After months of hard running and racing, I feel healthier than ever. My bodyweight is lower, my blood pressure is lower, and I feel stronger and fitter. I realize this is anecdotal, and I nonetheless may be damaging my heart.

While I remain open to evidence that suggests I should moderate my training, I am just as open to the idea that intense training may be neutral or even beneficial. As the author here so clearly argues, the ideologies, biases, habits and personal beliefs likely blind people to the science.

Thank you so much for this clarification. Though I paid attention to the original article which did acknowledge the small sample size, I did actually have a sleepless night over whether I should tone down my workouts. I used to run at least 20 miles/week, even in the winter, but gave it up in my forties for ballet, Pilates (including jump-board), and gym cardio. Still, the original article scared me, because I wondered if the study's conclusions could be extrapolated to other activities and thus the hours that I spend moving (and enjoying it) were going to have to be pared down in the name of health. This clarification really helped put my mind at ease by basically talking some sense into me.

Long time BMX rider with multiple knee injuries and torn ligaments in both feet here. I started running two years ago and recently completed my first marathon. I used to be a wreck due to my injuries, getting up in the morning was a task and a half, kneeling down hurt, and asking me to stand for longer than 25 minutes was purely out of the question. That being said, since I started running, my knees have never felt better and my feet are stronger than they ever have been. In fact, if I go longer than a week without a solid 10k or so, my feet and knees begin to hurt again.

Needless to say, more people should run. However, learn the appropriate technique to running so no injuries may come your way.

Or is it publication bias by the journal editors? It’s well known that the latest study, however flawed, always invalidates every previous study in the field and discredits all other researchers, or if the popular press story about it is clicked on more than 1 million times.

former runner here. several marathons. back surgery at 39. replaced hip ('birmingham method!' very cool for younger arthritis patients) at 47. sample of 1 i know...

president harry truman had a great quote regarding exercise; 'the the best exercise for a person over the age of 40 is a long hard walk.' he was very fit in his later years.

he also took a daily nap. ;)

sure i miss the runner's high, but my body just gave out. i watch most older people who run (over 50) and i just say 'ouch.'

gentle movement exercises; walking, swimming, yoga, etc is where it's at for most of us over 50. still, if your body can take it, a good run is a great thing. i do miss it as i said.

regardless of age; keep moving your body and watch what you eat.

The most important benefits of running or jogging are not about how long you live, but rather how well you live. Instead of trying to meet an artificial target created by someone else, do the speed and distance your body tells you is good for you.

Have you heard of Exercise Induced Hypertension? I had not till a friend I play tennis with began to look very pale after a long intense volleys. His resting BP is fine as is his HR but on his friends insistence he went in for a comprehensive cardiac evaluation. This man had been playing tennis most of his life, non smoker, thin , no alcohol, low lipids.
They had to stop the stress test when his BP soared over 220.It took 15 minutes in the treadmill for this to show. The cardiologist said if he had had any arterial weakness he would have stroked on the court or died.

All of us had never heard of this exercise hypertension and wondered if it was partly responsible for sudden deaths during running or other intense sports.
This would not show up on a routine physical because the BP only soars during anaerobic exercise. I'm not a Physician so I may not be accurate in my description of the problem but it was scary to learn that even with everything testing good you could have this very serious high BP with a normal resting BP .

I was hoping the nYT would look into this as when I research it the literature is saying it may be much more common than previously believed and possible responsible for deaths and strokes during exercise.
NY readers get tested, this information could save you as it did our friend.
Unfortunately there isn't a lot of research about exercise induced hypertension , sadly to be safe it means taking drugs and quit intense exercise.

I've seen studies like this before and, though I do believe they have more merit than the author credits them having, I think that ultimately they aren't really relevant to most people.

If you run a whole lot, think 10-15 marathons a year, then you can develop scar tissue in your heart over time which can be lethal.

However, the vast majority of people will not only do just fine off of 20 miles a week, but their health will improve significantly.

So, unless you are planning on doing 10-15 marathons in 2015 the problem is most likely not enough exercise. Not too much.

The Times has lately been endlessly encouraging people who work out to up the intensity of their workouts. I think that will work for some people, it didn't work for me: I injured my knee. I think it's a complicated question, too complicated for a one size fits all solution.

Is tobogganing unsafe for those in their 72nd year? Is playing Frisbee on 6 inch snow bad for such senior? It all depends what is your level of stamina and strength and flexibility. I did face-forward on Krazy Karpet and rolled over near the end. Would it be unsafe for someone who isn't fit, of course. But the real point is if you truly ENJOY it, go ahead -- even if it shortens your life after all it's your life. Won't you be willing to shorten your life for other more rewarding and meaningful ends, think of Martin Luther KIng who was probably unfit but had a more pressing passion driving him. Healthy life is a resource to be used in the service of a life that we enjoy at the deepest levels, not to flaunt and impress somebody including yourself.

I more or less gave up running after I got two puppies who wouldn't keep running because they wanted to stop and sniff something. 13 years later I have one 3-year old Irish Terrier Suzie and she will only run/walk for about 5 feet before she must stop to sniff. And so instead of running 3 days a week when I was a pup myself I now walk/run Suzie 5 days a week and pump iron the other two days. So far with my new routine I have only had a stroke and a painless heart attack, but at age 78 I am still kicking. Keep moving.

Moderation is the key. I was a daily runner for 30 years, logging about 45,000 miles. Little did I know what it would mean as I got older. As a daily runner, I thought I knew my body and would recognize any signs of stress. What I learned, however, is that the body lies. It's true, the mind and body work together to mask the damage being done, being done in very small increments that add up to major problems years later. I finally gave up running. Not that I had a choice. The back spasms were becoming more frequent and severe. Today, I suffer chronic pain, in my hips and along my spine, and many activities are unavailable to me. Running was a big part of my life, and I would run again if I had it to do all over again. But moderation would be my guide. I should have known; after all, I'm a cradle Episcopalean (everything is okay as long as it's done in moderation).

Lack of responsibility in publishing scientific information is certainly rampant in recent years. Media tends to place more weight on quotes of opinions of celebrities than what real scientists have to say about data. The way we have allowed pop culture and the media to demonize the american farmer and anyone who actually invests in industry may come back to haunt us when future generations have difficulty finding employment and use more of their incomes to feed themselves.

Thoughts from my daughter:

"This study seems very hard to interpret considering they are showing associations only. There are many factors that could be related to and "upstream" of running harder that may be independently linked to the mortality rate effect. Just as an example, maybe people who prefer to run harder are more highly stressed individuals who turn to running to blow off steam, and the constant high stress and *not* how much they are running is what is having an effect on lifespan. I don't think studies like this say anything about causation or how people should or should not change their exercise routines.

"Interesting nonetheless, and studies like this are helpful to initiate more mechanistic studies."

At one time, I focused on critiquing the quality of studies, and although legitimate, it could be wasteful. It also put the focus on individual studies. Over time, I realized the value of aggregation and the informal equivalent of meta-analysis, figuratively putting all the studies on the table and evaluating the entirety of data, rather than each part.

Thank for the article - helpful and informative, and shockingly necessary.

Over the last 3 years, its become increasingly chic to criticize and or disseminate negative-propaganda about running -- especially distance-running. A lot of this absurd anti-running / anti-long-distance media-content has originated more from veiled jealousy, laziness and negativity by those non-runners or former-runners who for whatever lead studies or simply don't run. Or if they do or did run, didn't put in enough effort to generate the extraordinary benefits from running: substantial strength-increases for mind, body & spirit.

There's a correlation between increased distance & intensity and increased strength of mind, body & spirit. Once your training-base is established, running 40 miles per week will generate better overall health-results than running 4 miles per week. You'll gain benefits from 4 miles per week, you'll gain even more benefits from 40 miles per week. Any suggestion otherwise is just another fad, like bare-foot running or eating a massive pasta-dinner before a marathon.

Running is the most efficient, universal exercise any person can do to improve their quality of life. Its the one true sport 99.99% of ALL healthy human beings, since the beginning of time, can relate to.

Don't believe the negative-hype: put your running shoes on and run as far and or as fast as you can, and in almost every case you'll be a better person for it!

HAPPY TRAILS!!

what the study really shows is the press mindlessly publishes anything it is handed. "News" sells papers and grabs readers attention. In a better world papers might exercise some judgement and refuse to print ridiculous studies like this, but it might cost them readers.

Really that this study hit the papers is more an indictment of the press than the study authors, who are merely responding to economic incentives "more study needed, so fund us for another round". They can write garbage but nobody forced the press to report it.

The same journal had a rebuttal in its editorial to this study, pointing out many of its critical problems, yet chose to publish the study as is, with those critical problems and faulty conclusions intact. Those problematic conclusions and methods should have been ironed out and the study most appropriately rejected for publication.

This study, revealing complete lack of understanding of statistical significance, is further evidence of declining math skills in the US, even among those with doctorates.

Its about like trying to predict an electoral outcome with a phone survey of 80 people.

Not hard to understand why we have people who think it is a good idea to not vaccinate their kids.

I have a problem with the original paper's definition of intensity, light, moderate and strenuous. A 12 minute per mile pace could be very strenuous for some, where a much faster pace could be light for others. Using something like percent of maximal heart rate would have been a better choice.

I'm stuck on the elliptical most days for the low impact value. I know a few people who have lived to be 100 who didn't exercise and several who were fit but died before 65. Always use good sense when you exercise and pay attention to injuries.

Fitness should really be about being able to do the things you enjoy. I like high intensity intervals, 3 days a week, weights 2x and outside time on other days. A good balanced routine should give you good posture, good sleep and endless endurance.

My brother pointed this article out to me.

I am 61 years old and work out in the gym every day for 90-120 minutes, alternating weights and aerobics. I don't see any reason to change, you really have to go hard to wear yourself out completely.

At last! Real journalism that doesnt accept a study's findings at face value. More please.