Evidence Against Excessive Cardio?

scottb81

Interestingly, the probability of any given individual being struck by lightening during their lifetime is 10 times greater than an individuals chance of having a heart attack while running a marathon.

The articles are using valid statistics but describing the results in such a way to greatly exagerate the risk. If someone avoids marathons only because of the risk of a heart problem then to be consistent they ought also to be living in a cave to avoid being electrocuted from the sky.

bumblebums

Interestingly, the probability of any given individual being struck by lightening during their lifetime is 10 times greater than an individuals chance of having a heart attack while running a marathon.

The articles are using valid statistics but describing the results in such a way to greatly exagerate the risk. If someone avoids marathons only because of the risk of a heart problem then to be consistent they ought also to be living in a cave to avoid being electrocuted from the sky.

Over the course of preparing my mega-post on page 4 (do I know how to procrastinate or what?), I read several papers by the research group who wrote the NEJM article. I have to say that unlike James O'Keefe, they are far less partisan in their conclusions. I would be inclined to trust their findings, and I do not think they misrepresent or exaggerate the risks of marathon running in the article. For example, they say the following:

"Thus, event rates among marathon and half-marathon runners are relatively low, as compared with other athletic populations, including collegiate athletes (1 death per 43,770 participants per year), triathlon participants (1 death per 52,630 participants),24 and previously healthy middle-aged joggers (1 death per 7620 participants). These data suggest that the risk associated with long-distance running events is equivalent to or lower than the risk associated with other vigorous physical activity."

The group also produced the study on runners vs. long-distance walkers that was covered in a recent NYT article linked earlier in this thread. They are definitely not a partisan anti-running fringe research group. And you are right that the effect size is fairly small, but it is significant. Nor does the direction of the effect contradict common sense. Are we really shocked to discover that some people have heart attacks after running 26 miles? The proverbial Marathoner #1 dropped dead, after all (although he probably didn't prepare for his run the way modern marathoners do).

BeachIron

Interestingly, the probability of any given individual being struck by lightening during their lifetime is 10 times greater than an individuals chance of having a heart attack while running a marathon.

The articles are using valid statistics but describing the results in such a way to greatly exagerate the risk. If someone avoids marathons only because of the risk of a heart problem then to be consistent they ought also to be living in a cave to avoid being electrocuted from the sky.

I see your point, but do you think that the risk of dying while running a marathon is all that significant to the question of whether "excessive" exercise increases one's risk for cardiovascular issues? The person who dies the next day wouldn't be included in such statistics. That said, I honestly doubt that the marathon distance is bad for people who have properly trained, but I'll leave that up to the researchers to determine.

I just want to note again that I posted this thread out of curiosity and this is not an attack on running. I have never been a marathon runner but I have put in my share of 30+ mile weeks and I absolutely love running. The article tweaked my curiosity about the issue because I have definitely learned the issues with over training with weights. I don't think it is too far of a stretch to think that the heart also needs a certain amount of recovery time.

Hexahedra

In case anybody misses it: I don't see anybody here saying cardio or running is inherently bad for your health. Just like food, too much and you become obese, too little and you starve.

I think nobody needs a research to understand that running a marathon every single day a year without a single rest day would be bad for your health. What the researchers are trying to figure out is at what point does physical exercise become counter productive to our health.

As for bodybuilding, it's perfectly possible to be fit and healthy with 20% body fat. Having six-pack abs is not a prerequisite to a healthy life; I'm actually willing to say that it's completely unnecessary as far as health is concerned, but it doesn't seem to hurt either.

scottb81

I think that most "long term" endurance athletes would admit that training for maximal performance is not the same as training for optimal health. The reason is that if one is training for maximum results they are always pushing the limit of either injury or sickness which is far above the amount of exercise needed for optimal health.

If someone repeately crossed the line into injury or sickness then there really is no argument that what they are doing is detremental to their health. However, if they manage to walk the fine line of extreme training without injury or sickness it is not clear from the data I have seen that that is detrimental tho their health. At the same time, the evidence would suggest that the extra training, while offering significant performance benefits, does not offer health benefits over more modest training.

In the end though, the biggest factor to longevity is probably genetic and not training at all although training probably will enhance the genetic factor.

Doodlewhopper

I think it would be impossible to quantify some mileage number that is too much because it is really about stress applied to the body over time. The amount of stress some number of miles applies to an individual is completety dependent on their fitness level primarily and several other things secondarily.

30 miles a week to someone unfit is going to crush them. 30 miles a week to a veteran distance runner is a very easy recovery week. The stress each of these two receives from this identical amount of work is not the same.

^^^^I agree. This is so basic I cant understand any not agreeing with it.

OP thanks for the thread and I understand where youre coming from.

Doodlewhopper

For every article like that, there is an article like this: http://well.blogs.nytimes.com/2013/05/29/is-it-better-to-walk-or-run/
Seems a recent study found that runners are better able to control their weight than walkers, and, as we all know well, excess weight is unhealthy.
So, does this one benefit outweigh the risks of changes in the heart, or vice-versa, or do they balance out.
Also, another recent study found the 50-year-old males who are in better cardiovascular shape have much less risk of developing lung and colon cancer, and are much more likely to survive if they do get it.
Personally, I would like to see the risks of weight lifting investigated. What if you drop it on your toe? Don't tell me it doesn't happen.

^ Absolutely irrelevant. The question has nothing to do with running vs. walking and everything to do with how much running is excessive. I'm a runner myself.

Completely relevant. You are saying running causes harm. This says running has benefit (forget the walking part of it). Don't you need to determine the risk you are going to get overweight and have a heart attack if you don't run versus the risk that running may stretch your aorta and it may burst in order to truly say: Don't run!
And isn't that really what we are trying to figure out here?
It is risk versus benefit. Not just risk. Heck, there is risk just getting up in the morning.
Sorry if I wasn't clear. I was trying to be brief and I thought the inferences were quite clear.

I did not see where the OP stated that running causes harm.

jonnythan

I think it would be impossible to quantify some mileage number that is too much because it is really about stress applied to the body over time. The amount of stress some number of miles applies to an individual is completety dependent on their fitness level primarily and several other things secondarily.

30 miles a week to someone unfit is going to crush them. 30 miles a week to a veteran distance runner is a very easy recovery week. The stress each of these two receives from this identical amount of work is not the same.

^^^^I agree. This is so basic I cant understand any not agreeing with it.

OP thanks for the thread and I understand where youre coming from.

They're talking about long term, not a single week.

"30 miles a week" means averaging 30 miles a week, every week, over a long period of time. Not a single week in some untrained person's life.

That's what all this is about. High levels of cardio over a long period of time. Someone who does 30 miles a week for years is by definition not "unfit."

Doodlewhopper

I think it would be impossible to quantify some mileage number that is too much because it is really about stress applied to the body over time. The amount of stress some number of miles applies to an individual is completety dependent on their fitness level primarily and several other things secondarily.

30 miles a week to someone unfit is going to crush them. 30 miles a week to a veteran distance runner is a very easy recovery week. The stress each of these two receives from this identical amount of work is not the same.

^^^^I agree. This is so basic I cant understand any not agreeing with it.

OP thanks for the thread and I understand where youre coming from.

They're talking about long term, not a single week.

"30 miles a week" means averaging 30 miles a week, every week, over a long period of time. Not a single week in some untrained person's life.

That's what all this is about. High levels of cardio over a long period of time. Someone who does 30 miles a week for years is by definition not "unfit."

Thanks for all your help.

GiddyupTim

For every article like that, there is an article like this: http://well.blogs.nytimes.com/2013/05/29/is-it-better-to-walk-or-run/
Seems a recent study found that runners are better able to control their weight than walkers, and, as we all know well, excess weight is unhealthy.
So, does this one benefit outweigh the risks of changes in the heart, or vice-versa, or do they balance out.
Also, another recent study found the 50-year-old males who are in better cardiovascular shape have much less risk of developing lung and colon cancer, and are much more likely to survive if they do get it.
Personally, I would like to see the risks of weight lifting investigated. What if you drop it on your toe? Don't tell me it doesn't happen.

^ Absolutely irrelevant. The question has nothing to do with running vs. walking and everything to do with how much running is excessive. I'm a runner myself.

Completely relevant. You are saying running causes harm. This says running has benefit (forget the walking part of it). Don't you need to determine the risk you are going to get overweight and have a heart attack if you don't run versus the risk that running may stretch your aorta and it may burst in order to truly say: Don't run!
And isn't that really what we are trying to figure out here?
It is risk versus benefit. Not just risk. Heck, there is risk just getting up in the morning.
Sorry if I wasn't clear. I was trying to be brief and I thought the inferences were quite clear.

I did not see where the OP stated that running causes harm.

You are right. I stand corrected and I apologize. He asked whether running causes meaningful harm.
I got that. i just misstated.
Now, at the risk of being tedious, let me try to better explain where I am coming from.
Most of this data is either not very good or has not been shown to be meaningful. It is observations in a population and some animal studies showing that if you elevate a heart rate for a prolonged period of time you can find evidence that the heart has been stressed. There is nothing more.
Now, let's consider the investigation mentioned in the New York Times blog someone posted, in which the researchers found fibrosis in the hearts of elite, endurance athletes who are older. That's interesting.Those investigators had age-matched controls and they found no fibrosis in their hearts. In the athletes, they found it was fairly common, about half had it.
But, there is no suggestion that this fibrosis was associated with any cardiovascular events in this population, or that it compromised heart function in any way.
So, let's say this damage is real and it is caused by running. That is not very surprising. We all take nicks and dings and have scars from whatever we do long-term. Football players have trick knees. Tennis players hurt their shoulders. Typists get carpal tunnel, for Christ-sakes! Kinda naive to think that runners wouldn't have some consequences.
And, really, to consider the question, you must put it in perspective -- some acknowledgement of the relative risk. That is to say, you have to consider what you would get if you didn't do it.
In the case of the elite athletes they might not have made a lot of money and been able to travel the world. They might not have learned so much about discipline and teamwork. They might not have garnered accolades.
More importantly, there are serious health consequences from not being active. They are worse and they have been shown to result in morbidity and mortality. They include obesity and type 2 diabetes, and heart disease.
So, would any of those elite athletes been better off if instead they had been sedentary and gotten fat at thirty and had a heart attack at age 50, a consequence of not exercising that is quite likely.
It is a consideration that is very relevant to this discussion, and it is what I meant in my first post when I noted that for every one of these "studies" suggesting too much running might be harmful there are 10 studies suggesting it is beneficial, sometimes in unexpected ways (may protect against cancer).
Would any of those elite athletes have made a trade off if they had known they might show a little wear and tear in the heart at age 50 years, and said: 'I think I will cut back a little'? Would any football player say to himself, 'You know, football is dangerous, I think I better quit'? And, that is an activity that clearly does have risk. Would any bicyclist say to himself, 'Riders get hit by cars, I think I will stay on the stationary bike in my living room'?
Would that ever make sense?
When you consider this question, you need to consider the alternative and put it in perspective.
Sorry if I ruffled feathers. I did not mean to. I simply meant to add something.

FYI. I have worked at a medical journal (JAMA). I can assure you we almost never published any paper in which the statistical analysis showed that the confidence intervals crossed 1, and if we did we would not have allowed the authors to draw any conclusions from such data. Granted, this situation might be an exception.

Hexahedra

So, would any of those elite athletes been better off if instead they had been sedentary and gotten fat at thirty and had a heart attack at age 50, a consequence of not exercising that is quite likely.

You truly have no intention of reading what others said, do you? It's not about running vs. not running, it's about HOW MUCH running is too much. If you are not a world class athlete who win competitions and jetsetting all over the world, is it worth running like one and pay the medical bills?

While there are many uninformed bodybuilders who are deathly afraid of cardio, none of them is saying anything in this thread.

GiddyupTim

I believe you are misreading me. Let me try the analogy again. If I go to the gym, I run the risk that I am going to drop the weight on me or that I will throw out my back. These are real risks. These things happen.
But, hey, if I did not go to the gym I would be safe. Or, maybe I should reduce my gym time -- just run in, do one or a few exercises and run out -- because clearly the longer I am in the gym the greater my risk.
Should I do that?
Heck no! We all know that. The health and appearance benefits of weight lifting increase greatly the longer I am in there.
Now, I could go around and collect a whole bunch of cases of people who have injured themselves in the gym. Would not be hard. And, I could perform a whole bunch of statistical operations on their rate of injury relative to the time they spent in the gym (and ignore the fact that my statistics are telling me I don't have much here), and publish anyways, and it would look impressive.
Then I could take muscle biopsies of gym participants right after they are in the gym, and I would find that their muscles fibers have been damaged and are remodeling.
There is a lot of indication that this is what is going on here. These investigators are really not finding very much, and their own statistics bear that out; They are just choosing to ignore it.
As Scott said: You have a greater chance of being hit by lightening, than dropping dead from a marathon, the most demanding, rigorous running you can do. Should i live in a cave, therefore?
Or, I'm sorry, the question should be -- cuz I gotta eat -- how much time should I spent in that cave?

zornig

It's funny how there are such distinct lines drawn between cardio lovers and lifting lovers... I have heard both ends of it and decided to do my own thing. I eat a lot of protein like a lifter, but focus mostly on cardio and less on weight training like a runner. I think both ends of the argument would just tell me I'm all wrong

I think it's mostly the runners who resist on the cardio side, and the powerlifters who resist on the lifting side. Cyclists and swimmers, for example, are far more likely to incorporate lifting into their regimen. Big lifting dudes don't like running because of all that weight slamming onto the knees!

CrazyTrackLady

I hesitated to post this but it's from the WSJ and it discusses what appears to be growing (at least anecdotal) evidence against excessive endurance exercise. I run regularly so by no means is this an attack on running, but perhaps it's wise to think twice before deciding that marathons are the way to go if you are not currently a marathoner. The point is simply that there may be an upper limit to the amount of running that is beneficial, above which running may start to cause or exacerbate cardiovascular issues. That said, this does not have links to any underlying studies and that is a clear weakness in the article.

http://online.wsj.com/article/SB10001424127887323975004578501150442565788.html?mod=trending_now_4

From the article:

"Research shows an association between endurance athletics and enlarged aortic roots.

Other recent studies suggest the significant mortality benefits of running may diminish or disappear at mileage exceeding 30 miles a week and other, very small studies have shown elevated levels of coronary plaque in serial marathoners—a problem that rigorous exercise theoretically could cause."

This is a very important caveat from the article:

"Yet sports-medicine specialists are sharply divided over whether any warning is warranted. For every American who exercises to extremes, after all, there are thousands who don't exercise at all—and who might embrace any exercise-related warnings as cause for staying sedentary. Moreover, the evidence for extreme-exercise hazards is far from conclusive —and is contradicted by other studies suggesting the health benefits of exercise may accrue to infinity." [emphasis added]

Running to me has always looked B O R I N G and painful. I love cardio workouts, but I prefer a little more variety in my routine than just moving forward at a steady pace. Plus, it appears to be very destructive to joints and pelvic bones. Just my opinion.

55in13

Different strokes; I prefer running because it isn't as boring as being in the gym, but I run where I see nature.

On the main topic, I am a little late throwing this out there, but it only occurred to me this morning, while running. What about the time of day correlation? Lots of studies have shown heart attacks are more prevalent in the morning. When are most long runs held? My perception may be skewed because I live where it is warm most of the year, but the vast majority of long runs here start before 9:00 AM.

BeachIron

Running to me has always looked B O R I N G and painful. I love cardio workouts, but I prefer a little more variety in my routine than just moving forward at a steady pace. Plus, it appears to be very destructive to joints and pelvic bones. Just my opinion.

This thread is about a very specific point and was primarily aimed at other runners. I suspect that if you have joint and pelvic problems, or find running boing, you will be able to find many alternatives.

jonnythan

Running to me has always looked B O R I N G and painful. I love cardio workouts, but I prefer a little more variety in my routine than just moving forward at a steady pace. Plus, it appears to be very destructive to joints and pelvic bones. Just my opinion.

This thread is about a very specific point and was primarily aimed at other runners. I suspect that if you have joint and pelvic problems, or find running boing, you will be able to find many alternatives.

I though it was about extreme amounts of cardio, not just running.

BeachIron

Running to me has always looked B O R I N G and painful. I love cardio workouts, but I prefer a little more variety in my routine than just moving forward at a steady pace. Plus, it appears to be very destructive to joints and pelvic bones. Just my opinion.

This thread is about a very specific point and was primarily aimed at other runners. I suspect that if you have joint and pelvic problems, or find running boing, you will be able to find many alternatives.

I though it was about extreme amounts of cardio, not just running.

I used "cardio" in the thread title, and perhaps that was a mistake, but the studies and articles cited in here have all been focused on running. I suspect that the results would be applicable to endurance athletes of all stripes but the distances involved would, of course, vary. In any event, endurance training would involve "steady pace" so it would not applicable to the above poster.

jonnythan

Nm

neandermagnon

I have been trying to find the "right" amount of running for several years. I've been in a running group that was trying to convince me I was eating too much protein and lifting too much, and then with the lifting groups telling me that I was eating too many carbs and that running is going to destroy my lifting progress. We all have to find our own approaches but I'm seriously trying to find the sweet spot for the maximum health and appearance benefits.

AFAIK the issue is getting enough to eat, I've not seen any studies that suggest that running makes you lose lean body mass or prevents you gaining it if you're eating enough. Hard gainers would be well advised to avoid cardio, simply because they already struggle to eat enough to make the gains for lifting. Doing more cardio would necessitate eating even more, so it's counter-productive for someone who already struggles to eat enough. However if eating enough is not a problem then I don't see how doing any kind of cardio would prevent muscle gains from lifting.

I've seen quite a few articles with reference to studies on endurance runners that suggest an increase risk of heart problems... HOWEVER there are so many people who do excessive cardio while not eating enough, and I haven't seen reference to any studies that control for this. I don't doubt at all that excessive cardio on insufficient food intake for long periods will harm the body.... but I also fail to see how it's harmful for you if you eat properly to support the running you're doing. Here's my take on it (from an evolutionary perspective): http://cavepeopleandstuff.wordpress.com/2013/05/16/running-is-bad-for-you-because-what/

It seems that people like to get into "camps" depending on what kind of exercise they prefer. There's the long distance running camp that says too much lifting and too much protein is bad, then there's the heavy lifting camp that says endurance cardio is bad for you. From what I can see, what does the damage is insufficient nutrition and insufficient time to rest and recover. The human body is remarkably adaptable, but does need to be fed properly and given adequate rest and recovery time.