Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

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Still not born to run

The original cardio causes heart disease post is still one of the most-linked and viewed on the blog

Now reader Ben has alerted me to this article on a presentation given at the ACC (American College of Cardiology) meeting.

ATLANTA -- A group of elite long-distance runners had less body fat, better lipid profiles, and better heart rates than people being tested for cardiac disease, but, paradoxically, the runners had more calcified plaque in their heart arteries, according to a study reported here.

Investigators performed computed tomography angiography on 25 people who had run at least one marathon a year since 1985, according to senior author Robert Schwartz, MD, of the Minneapolis Heart Institute and Foundation. They compared the athletes with 23 control patients who were undergoing the same scan for symptomatic or suspected heart abnormalities.

In controls, the calcium plaque volume was 169 mm3compared with 274 mm3 for the elite runners (P=0.028), the researchers reported at the American College of Cardiology meeting. The runners also had a higher calcium score and higher noncalcified plaque volume, although those differences did not reach statistical significance.

So if you recall, in the German study I wrote about in Cardio Causes Heart Disease, they found that there was more myocardial damage (actual heart attacks) in runners than "risk factor" matched controls and about the same compared to age and sex matched controls.

Meaning; a given runner in the German study could be predicted to be more likely to have had a heart attack by MRI than a person with the same age height weight , smoking history, etc., who was sedentary. Take two subjects who otherwise look the same from a risk standpoint (which we know is kind of worthless anyway) and the sedentary one is more likely to have healthy coronary arteries.

And if compared to a person of the same age and sex, the runners in the German study had about the same chance of having had a heart attack, but this was despite being less likely to be obese, hypertensive, smoke. etc., all those things that cardiologists tell us "cause" heart attacks.

Now we have a group on a different continent, only 7 hours away from me in Minnestoa, who read the German study, and sought to replicate it using CCTA.

Sidebar: CCTA is coronary CT angiography - this is actually a two part test where a CAC or coronary artery calcium score is first assessed, then contrast is given so the inside of the coronary arteries can be seen - this two step test allows both calcified plaque and non-calcified plaque that is invisible on a simple CAC test to be evaluated

They did this CCTA on 25 marathon runners they recruited, and compared them to 23 age and sex matched controls and it looks like the runners had more coronary atherosclerosis than the controls by all three numerical parameters of the CAC part of the exam. Only the plaque volume reached statistical significance, though.

Some things to note:

This is a tiny study. To get statistical significance with this few patients is, well, perhaps significant (clinically)

Read the bit about the controls:

"...control patients who were undergoing the same scan for symptomatic or suspected heart abnormalities.

Did you catch that?

The control population was not asymptomatic normal volunteers, it was drawn from people who had symptoms (chest pain and shortness of breath, etc.) or who had symptoms and had a previously abnormal test - usually a test known as MPI - or nuclear medicine myocardial perfusion imaging - usually called a "stress test" in the vernacular. How do I know this if the abstract does not say this? I do these exams every week at my imaging center, so I know why they are done.

So the controls came from a population that has (Bayes theorem here) a much higher a priori probability of having coronary disease than average, and yet the runners still beat them in having more evidence of coronary atherosclerosis.

That is really very impressive, and not in a good way. I'll do a longer post when the paper is published.

My three hypotheses all remain viable:

Weak form: Chronic Steady state aerobic training* (CSSAT) does nothing to prevent or reverse atherosclerosis

Mild Form: Some effects of CSSAT may be beneficial or neutral, but they are overridden by the inflammation promoting effects of the diets favored by those who train this way.

Strong Form: CSSAT itself promotes the inflammatory state via cortisol, cytokines, inadequate recovery, etc.


* I am using the word training to include both the weekly running and the long events, as it is impossible so far to distinguish the two


PS - If anyone has access to the actual abstract or has seen the presentation, maybe you can forward that to me..

Here is the title:

Schwartz J, et al "Does longterm endurance running enhance or inhibit coronary artery plaque formation? A prospective multidetector CTA study of men completing marathons for least 25 consecutive years" ACC 2010; Abstract 1271-330.

Reader Comments (19)

This is incredibly important...investigation is happening, people are questioning the status quo. Finally! Looking forward to your post after the paper is published. Thanks for helping to keep me aware :)

March 21, 2010 | Registered CommenterGina R

And yet they will still run. I have friends that run. At least two of their three triplets (they all do cross country at their high school) have repetitive use injuries from running. When they ask me the best thing for those injuries, I said "don't run". And still they run. I can show them any study. But in their mind, if you're running, then you're fit. You are noble. You are a runner.

March 21, 2010 | Registered CommenterDave RN

I fear this will be another one of those seminal pieces of work that is largely ignored because it does not match up with what people want to believe. I get the same thing all the time when trying to convince fellow cyclists that short & sharp is superior riding all day. It wouldn't matter what level of evidence I presented (well it would - if Lance trained that way, then they would do it too... stupid thing is, Lance does do a snotload of high intensity training), they don't want to listen.

I agree with Dave running = skinny and skinny = healthy.

I love the action points sidebar on the Medical News link:
"Explain to interested patients that this is a small study that needs further investigation and should not be used as the basis for reduction of exercise, which typically improves heart health."

That just seems like more BS to maintain the status quo & not upset people. You hear the same things from nutritionists/dieticians (I'm a nutritionist), e.g. "despite the evidence, high fat diets remain unproven and we are unsure of their long term safety, so we recommend you don't change a thing."

I saw this recently with a dietician hear in New Zealand saying high fat eating hasn't been proven to be safe in the long term and then a couple of weeks later was on breakfast TV congratulating McDonalds for getting into bed with Weight Watchers! Craziness.

Thanks for the update post Doc.

March 21, 2010 | Registered CommenterJamie S

"Strong Form: CSSAT itself promotes the inflammatory state via cortisol, cytokines, inadequate recovery, etc."

Definitely betting on that one, especially having read "Why Zebras Don't Get Ulcers."

I always find the "running=skinny and skinny=healthy" funny because mostly ever person I train that comes in with a runner background tends to be "skinny fat." Thin, very little muscle mass and they hold all their weight around their middle. Even if they are exceptionally lean everywhere else, they seem to hold just a bit around the stomach and love handles....insulin/cortisol??

March 21, 2010 | Registered CommenterBen W

True for enduro cyclists too Ben... skeletal upper body, soft through the middle. You often don't have to dig too deep to find many markers of poor health (chronic injury, recurrent illness, poor body comp, etc).

March 21, 2010 | Registered CommenterJamie S

I have had more than a few HS students who are dragged in to see me by their parents because they faint during the cross country races or workouts (both in NY and in HI) the kid is usually happy to take a break while tests return from the lab and the MD gives the ok. I help them look at their life from a less competitive and nourishing point of view, generally they show interest. The parents on the other hand want them back training asap...even carrying water if the coach has orders to keep them benched. Seems the indoctrination begins early and right at home.

March 22, 2010 | Registered CommenterGina R

Michael Ross, MD, a physician and trainer of some elite national class cyclists, came out with a book in 2005 called "Maximum Performance For Cyclists". His training regimens emphasize qualiity over quantity. He backs up his theories with some compelling explanations of the science behind why this works and also by the results of his athletes. Many other coaches, including Lance Armstrong's coach Chris Carmichael, are converting to the emphasis on high intensity, lower volume training.

We cyclists used to refer to high mileage training days as junk miles, but necessary. They are still junk miles, but, happily, unnecessary.


March 22, 2010 | Registered CommenterRichard M

Have reposted the original article for the British market

March 22, 2010 | Registered Commenter Dr Rohen

Contrarian position: If we sat fat eaters dismiss traditional heart risk factors because they do not actually predict negative health outcomes, why is it that we are willing to accept studies such as these which measure "risk factors" without checking their predictive power?

To answer myself, I tried to google around and find statistics on the mortality of people identified as "marathon runners" or "runner(s)". I couldn't find anything that directly answered the question (although there's a lot of controversy out there over people keeling over and dying during events themselves). I think my google-fu has failed me, or perhaps the statistics do not exist. In any case, the contrarian position still demands a rebuttal: If marathon running generates a risk profile comparable or worse than people who are at risk for the disease, does that actually translate into a comparable or worse rate of death/comparably negative health outcomes?

March 22, 2010 | Registered CommenterPhil W


We don't reject them ALL - obesity and smoking and hypertension and diabetes are absolutely risk factors for CAD

We only reject the blood lipids BS - very important distinction!

So these non-lipid framingham type type risk factors that are not necessarily the whole story, nevertheless they do help us predict in some fashion who may have CAD.

What they are in turn caused by is irrelevant - the point is that there is something about CSSAT that makes you (according to 2 studies now) MORE likely to have heart disease than one would expect based on these other risk factors.

March 22, 2010 | Registered CommenterKurt G. Harris MD

Good point on the risk factors. I was thinking "cholesterol" when I said that but obviously there are others which are better correlated with actual risk, ie the ones being discussed in this study. My thinking was that since I've rejected the lipid hypothesis in part because of its failure to actually predict negative outcomes, I should look at that same relationship with respect to CSSAT in order to maintain rigor.

Given that I failed to establish anything there, I was also hoping to crowdsource the search for any correlation between CSSAT and either heart attack or death in general. I'm still looking, but if any other folks have a lead let me know or post it up. Mortality in CSSAT athletes seems like a decent pragmatic test of the hypothesis put forth in this post, even if it wouldn't directly confirm or deny it and of course be heavily confounded by other factors.

March 22, 2010 | Registered CommenterPhil W

Re-read the original cardo causes heart disease post. Evidence of myocardial scar from heart attack IS what they measured. The current study looked at coronary disease, which is necessary but not sufficient for a heart attack.

One would need a pretty large sample to look at mortality.

March 22, 2010 | Registered CommenterKurt G. Harris MD

When people see how skinny I am, they often ask if I run or jog. I've hated it all my life. I took a biomechanics graduate course with Owen Lovejoy at Kent State University (an expert in hominid biomechanics) and discovered just how bad running/jogging is on the human skeletal anatomy--especially the knees. My response to people who ask if I jog has always been that it's against my religion. (Funny, I always expect them to ask what religion that is--to which I'd reply human nature--but oddly they never do ask!)

March 22, 2010 | Registered CommenterAaron B

Thanks for the heads up. I think your suggestions for why this might be occuring are intriguing and I hope that someone will actually test some of these factors. Is inflammation correlated with the increased plaque? Or is it the high processed carb diet? or both? These paradoxes are the first step to wisdom, to asking the right questions. This paradox provides incentive to actually dissect the different factors contributing to atherosclerosis from a different perspective.

That said, as a runner, I greatly enjoy the wind in my face and the thrill of freedom and mobility running provides. I cannot believe that there is anything inherently unhealthy about it, anymore than that there is anything inherently unhealthy about eating. But that doesn't mean there aren't health promoting ways to do it as well as potentially health damaging ways.

There are plenty of people with great body composition who are runners too, so it is not necessarily true, as some commenters believe, that running and other endurance sports necessarily lead to hormone imbalances and excess cortisol, just like I don't believe that a low carb diet necessarily leads to hypothyroidism, as some have suggested. Diet and exercise can affect hormone balance though, but people are often unaware of the consequences and unable to make adjustments that are needed.

I'd be interested to see a comparison of controls with athletes of other sports. I'd conjecture that the body builder/weight lifting crowd might appear healthier, not because their chosen exercise is inherently healthier, but because this group is more likely to be interested in body composition, to restrict carbs and eat ample protein, rather than believing they can shovel in any garbage they want and get away with it.

March 22, 2010 | Registered CommenterCynthia M

Aaron b, I get accused of being a runner too because of my build (tall and thin). The only time it was a compliment was when I had a cardio checkup (nuclear stress test) and I did so well (they finally told me to stop. Not only could I keep going, I was able to hold a conversation while doing it), they said, you're a runner right? "No" I told them, "I believe running is harmful". They looked at me like I was from another planet.


Not to rain on your parade, Dave but those nuclear stress tests are worthless for detecting anything but rather severe CAD, and often they miss that, too. I think these tests are particularly pointless if you are asymptomatic.

In the upper midwest, anyone over 40 with a waist size under 40 inches is assumed to be a runner:)

March 22, 2010 | Registered CommenterDave RN

Dr Kurt said..."In the upper midwest, anyone over 40 with a waist size under 40 inches is assumed to be a runner:)"

Ha- what a world we live in!

March 23, 2010 | Registered CommenterGina R

Lots of runners, particularly marathoners, have bought into the idea of carb loading before a race and in training, which could be a confounding factor. Postprandial glucose spike anyone?

Or so I'd like to think, anyway. I've signed up for the Chicago marathon this year ...

March 30, 2010 | Registered CommenterStephen

The other day as I was driving somewhere I saw a young woman, somewhat overweight, running like crazy with a terrible grimace on her face, clearly in all kinds of pain but pushing through. In the past I would have been saying something like, "Good for her... I wish I had the time and motivation to do that." Now I find myself saying, "Poor thing. She clearly hasn't gotten the word yet that she is doing absolutely nothing of benefit to herself." The other thing is, the boob factor. It simply cannot be good for women, especially busty women, to be putting that kind of stress on their breast tissues day in and day out. I imagine that, even with the best kind of support, the repeated trauma that the breasts are taking cannot be a good thing. Wasn't there some study in the past that suggested that excessive bounce is a risk for breast diseases?

April 4, 2010 | Registered CommenterPatricia C Psy. D

I'm of a few different minds when it comes to this issue. On the whole, I much prefer and definitely recommend interval training and sprints over steady state cardio when it comes to both weight loss and to improving performance. However, like a few others on this blog, I wonder if there aren't some compounding issues:

Obviously the first is that many of these runners are probably eating a high-carb and inflammatory diet because they believe they need that to fuel their performance. Also, they may not be taking adequate recovery. Perhaps one or two runs a week is not enough to cause an increase in the risk of heart disease.

It was my understanding that humans DID in fact evolve to run. Whether as persistence runners, scavengers, or what not. Aaron B, I think that we have many great adaptations to run. Recent research is showing that many of the injuries associated with running can be mitigated, if not eliminated, by a more natural forefoot strike. One recent study that comes to mind found that going barefoot was better than going shod for patients with osteoarthritis in their knees. I can't comment on the "boob factor," however.

Another possibility that I think is contributing to some of the heart disease markers is pollution. Though I don't know the studies off the top of my head, I am fairy certain that it has been shown that air pollution can contribute to heart disease. It seems likely to me that the people who were running the most marathons in this study were also spending proportionately more time running on the streets and sucking up car exhaust, etc.

If any of this is a repeat of a previous discussion, I apologize. I am new to the blog and find your discussions very interesting. I am happy to be able to contribute and look forward to continuing to read your responses.


We may be evolved to run in some sense but there is running and there is running. I think at some point very high amounts of time spent near maximal aerobic effort with inadequate recovery- whether, running cycling, paddling, etc. is inflammatory. Even among persistence hunters, they don't run at max heart rates continually like a marathon, and I doubt if this was done as ubiquitously or as often as those who fantasize about it think. For one thing, it only works in very open environments. Try it in Wisconsin cedar swamp some time..

I run 10K or so a week in nice weather. I do believe some sprinting and shorter runs may make you be healthier than being sedentary. I think there are definite mood benefits to some kinds of repetitive exercise. Where the transition occurs between a few K a week and being a marathoner I don't know. I suspect it is just too much work with inadequate repair time.

One very important point is "the heart is not the heart".. VO2 max is NOT measuring plaque on your coronary or carotid arteries. IN fact, VO2 max is exercise specific.

April 8, 2010 | Registered CommenterSteven S
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