Does “Cardio” Cause Heart Disease? Dr: Harris: “Yes”

Well here’s another post that’s merely to point you to someone else’s good work, but I just can’t pass it up. One of the great recent additions to the paleo blogosphere is Dr. Kurt Harris, also a reader and commenter here.

Here he really does his homework and puts a number of studies together — backed by his specific expertise in radiology — to demonstrate that, as he says:

Running a marathon is looking about as smart as boxing or playing football.

But here’s the bottom line, comparing 102 experienced, long-term marathoners with 102 age-matched sedentary folk.

Would you believe 12% of asymptomatic marathon runners had evidence of myocardial damage on LGE?

Would you believe that among the sedentary controls only 4% had abnormal LGE?

Go have a read at the whole post, which is quite comprehensive.

By the way, I — as everyone else back in the 80s — thought running was just a super healthy thing to do. From about ’82 into the late 80s I’d run from time-to-time, and at times, might do upwards of 15-20 miles in a week. Did some 10Ks, and did 10 milers a few times.

But other than running in the cold rain, which I did love doing, I always pretty much hated it. But, see, in a world that runs on guilt, shame, self-denial and sacrifice, this was proof positive that it just must be good for you, just like, y’know, taxes, regulations, fines, levies, restrictions and all manner of stuff you hate for yourself but see as good for everyone else. We seem to be susceptible to erecting all manner of "necessary evils" to tolerate and embrace "for our own good," depraved as we all are. So, running is like confession and penance.

Does it make sense that something most of us naturally hate to do would be particularly healthful? Wouldn’t the paleo Principle suggest that it’s more likely harmful? If most people hate trudging along, then it can’t possibly be something we evolved doing regularly or to great extent (brief running and sprinting, absolutely), which means that we’ve not particularly adapted to it, making it somewhat of a crapshoot to engage in the behavior.

It certainly was for the three unfortunate runners who all collapsed and died in the space of six minutes during the recent Detroit Marathon.


Since Covid killed my Cabo San Lucas vacation-rental business in 2021, this is my day job. I can't do it without you. Memberships are $10 monthly, $20 quarterly, or $65 annually. Two premium coffees per month. Every membership helps finance this work I do, and if you like what I do, please chip in. No grandiose pitches.

30 Comments

  1. justin on November 2, 2009 at 11:54

    >Does it make sense that something most of us naturally hate to do would be particularly healthful?

    I actually loved to run as a kid but running then was play it wasn’t a means to “get in shape,” “lose weight,” or train to run a race.

    Meanwhile, the older I got the more my shoes got clunkier — from Converse all-stars to those goofy Pumps and worse.

    However, now I find running to be much more interesting and fun — go run in your VFFs on a trail through the woods and tell me that’s not fun.

    Anyway, I think the key is that running should either be very low-intensity (and low impact) and *definitely* in minimalist footwear or barefoot or it should be very intense as with sprinting. Distances should vary, pace should vary, etc. It shouldn’t be this chronic, steady-state, cardio as punishment. It should be play — you lose that and you miss the point.

  2. jacobus on November 2, 2009 at 12:26

    On the other hand, there is Persistence Hunting, ain’t nothing more paleo than that.

    • Richard Nikoley on November 2, 2009 at 14:27

      That’s hardly chronic cardio. Not like they do that every day, perhaps not even every week. Plus, from what I understand they use specialists. Not everyone does it (maybe because they understand that while necessary, probably not terrifically healthy)

      • nordic caveman on November 3, 2009 at 00:24

        the fact that only a low number of tribes are doing the persistence running (one that I know of) tells me that it is an exception.

        It does not make sense. Why, instead of sneaking and spearing the animal, assuming that tribe has not invented the bow, they choose to run unnecessary distances around the open country? Lack of technology? Lack of strong arms to throw the spear over long distances? Something is there.

        More likely it is due to the lack of some other things rather than the suitability of the human body to long distance running.



    • Mojo Yugen on January 4, 2010 at 08:26

      The persistence hunting argument rings true for me. I do believe we evolved to be a long-distance running animal. I’m also someone who enjoyed running (long and short distances) growing up and was able to do it (mostly) injury free. I had to stop the past 8 years or so mainly due to weight but now (thanks in large part to paleo principals) I’m back down to a “running weight”. I also started running in VFF’s (Vibram FiveFingers) and occasionally barefoot. That made an amazing difference in how I run and now I believe that the major problem with running is our shoes. For me that also reconciles nicely with paleo-principals, I’m pretty sure we didn’t evolve to run in Nikes.
      As far as only a few tribes doing persistence hunting, well of course, persistence hunting was mainly done before we had tools, once you have a spear with a nice stone tip you don’t have to run the animal to death, just sneak close enough to chuck a spear. To me that’s kinda like saying the slide rules weren’t very useful because no one uses them anymore.
      I’d recommend the book “Born to Run” by Christopher McDougall for anyone who cares about this topic, it’s the book that really changed my mind about running and let me start enjoying running again.

  3. dave, RN on November 2, 2009 at 12:27

    I have a friend that runs. He has triplets that also run cross country. So far 2 out of 3 have repetitive use injuries, and they’re just 17. And yet they still run. They considere it to be a noble and healthy thing to do. I’ve told them otherwise, and how many teenage girls that run already have enlarged hearts, but to them it’s a measure of manhood, womanhood and success in their family. If you can run far, then you’re better and more healthy than everyone else. I just hope I don’t get a call that he dropped dead while running (he’s in his early 50’s).

    • Mojo Yugen on January 4, 2010 at 08:10

      They are running wrong.

  4. Bay Area Sparky on November 2, 2009 at 13:48

    I don’t think there’s any question that chronic distance running would have an overall negative affect on the majority of the population. There are always exceptions of course but viewed purely from a common sense standpoint, it would be hard to argue for its benefits over its liabilities as they apply to the vast majority of people. This is especially so when running is viewed in the context of other forms of exercise and the benefits that can be achieved at lower levels of distance and time spent.

    The body is a mechanical device. Biomechanically, excessive running would wear down joints, valves, etc which in my view have a finite number of repetitions built into them. Above a certain level of exercise, you are just wearing down your body…similar to putting lots of mileage on a car.

    The heart is a muscle. It should be exercised within reasonable means. But there is a difference between being fit and overtaxing your body on a regular basis. And there is a difference in exercising the heart and wearing down the rest of the body as well.

    I do just enough cardio to keep my heart and lungs and diaphragm in shape. But as I near the age of fifty, I take care not to overdo it. Running in moderation can be a great benefit because of it’s effects on the heart, lungs, muscles, etc. But if you’re after a pure cardio workout, there are any number of ways to achieve that goal without running. If you’re after the specific, muscle-related benefits of running, there is probably no substitute (in spite of my swimming and cycling workouts, my legs lack explosion when playing basketball or even softball, if I’m not running as part of my regimen…even intense walking doesn’t address this lack of explosiveness either). In some regards there’s no substitute for running. But people need to know what their fitness goals are and consider to what degree if at all, distance running workouts help them achieve these goals.

    For every individual there is a workout that can be tailored to your needs whatever they may be.

  5. Marnee on November 2, 2009 at 14:03

    Let us keep in mind that runners are notorious carb junkies. The low carb cohort of the running community is often ridiculed.

    Running is like their big excuse to eat enormous amounts of processed sugary crap, before, after, and during a run. So the link to myocardial damage is probably more greatly linked to the diet plus the running rather than the running alone.

  6. Tim Rangitsch on November 2, 2009 at 14:15

    Marnee, the control group was non-runners, eating the same SAD carb intake. So the study was pretty well showing that there was a correlation to marathon training/running with heart troubles. There was no group of low carb runners to compare.

  7. Richard Nikoley on November 2, 2009 at 14:18

    Reader David McCracken had technical issues, so I’m posting this comment for him.

    ~~~

    Running was a crucial skill for pre-neolithic man – whether running down wounded prey, pacing prey, fleeing from predators or other reasons. It would vary from all out sprints to steady loping, to “hurry up and wait”. You’ve linked to Erwin LeCorps before, and he shows incredible grace in his running. People should look at him on video to appreciate what the human form can do. It is beautiful.

    Where people can go wrong is in over-focusing on a particular aspect of any skill. Paleo man needed strength, aerobic capacity, high lactic tolerance, endurance: the sort of thing you would get from training both fast twitch and slow twitch muscle, typically with a mixture of burdens over intervals and distances. Hmmm. Sounds a lot like LeCorps’ training, and for that matter what we put ourselves through in the infantry.

    Focusing on nothing but long distance is kind of like teaching a pilot how to maximize glide performance, and not how to land.

    Personally I am really enjoying being able to run again. I ditched wheat 9 months ago and also started certain supplements. The changes have been slow but steady in weight and physical performance. I can now say that my knees have been pain free for a month (a first for nearly 20 years). I generally run about 6-9 km 3-5 times a week. My speed is improving, joint stability is good, muscle tone is good. I have little interest in marathons, unless I end up doing one just to say I did. I’m targeting 10km in 40 minutes, and whatever I can do in an hour. The guiding principal is what feels good. The real objective isn’t to be a road runner. I love hiking in mountains, for which you need leg strenth, aerobic capacity, endurance and the ability to carry weights. Running outdoors on hilly courses is good conditioning. it is also a form of meditation.

    I just came back from a holiday on which I did some nice hikes. I can report that one I use for calibration I now complete in HALF the time that I used to 10 years ago, and it felt really comfortable.

    Don’t slag cardio. Slag narrow focus on unbalanced fitness agendas.

  8. Michael on November 2, 2009 at 14:20

    Good ‘ol Protestant work ethic. If you hate it – it must be great, it you love it – it must be a sin.

  9. mgood66 on November 2, 2009 at 14:21

    After reading Primal Blueprint, I sort of got the impression that the term “cardio” is referring to activity that causes extremely high heart rates associated with running, high-intensity activities, etc.

    So, if I monitor my heart rate, as described by Mark Sisson, to keep it under 75%, while I’m on the treadmill/stairmaster, am I still engaging in a counter-productive activity if my goal is weight-loss and overall improved health?

    • Richard Nikoley on November 2, 2009 at 14:49

      mgood66:

      It depends how long and how often. I’m of the opinion that treadmills and stairmasters are of almost no benefit and mostly serve to make people hungry.

      At our gym, all the fatties are constantly on the cardio equipment (you never see them doing anything else) while all the lean people are pushing weights, playing basketball, swimming, raquetball, or handball.

      • nordic caveman on November 3, 2009 at 00:34

        Also I am of the impression that running on a treadmill is not the way the knees were intended to work, thus a treadmill is the fastest way to ruining your knees other than smashing a hammer on your knee.

        See, when running, the foot strikes the ground while the body is already propelling forward. So the first strike of the foot server to keep the body up and then continue the forward motion.

        With a treadmill the body is stationary. So the first strike of the foot will try to keep the body stationary in spite of moving ground (treadmill’s band). this means that the first strike of the foot is not to keep the body up, or keep the body moving, but to stop the band. It is not a neutral/backwards movement, it is a forward slap of the foot.

        This, will injure the knee, unless the person has perfect treadmill running technique.

        In my gym also, the fatties are on the machines, and the guys who want to lose weight are on the machines, cycling for an hour or so. (cycling outside is different.. hill up, hill down, red light, wind spirnt…), the guys in best shape are either the ones pushing weights, or training with their body.

        When i last said I do no cardio, the way they do it, the eyes opened in disbelief, while I was enjoying the burn of a kettlebell set in my buttocks.



  10. Kurt G Harris on November 2, 2009 at 15:24

    Hey richard, thank you for the kind words

    “At our gym, all the fatties are constantly on the cardio equipment (you never see them doing anything else) while all the lean people are pushing weights, playing basketball, swimming, raquetball, or handball.”

    At my local Y, it is exactly the same. The free weight room is 100% lean and the room with the stairmasters, treadmills and elliptical machines is all central obesity. I want to take photos and post them on my blog, but can’t for obvious privacy reasons!

  11. Trish on November 2, 2009 at 20:17

    I couldn’t help but notice the ages of the three who died during the Detroit Marathon–one was 65, but the other two were 36 and 26 respectively. Not old farts–young guys. 26-year-olds shouldn’t be dropping dead.

    I used to be a cardio queen, but now I go for the free weights (I use a gravitron for pull-ups). I go to a yuppie suburban gym so I always have access to the weights while everyone else is slogging on the ellipticals and treadmills.

  12. collagen on November 2, 2009 at 20:28

    I have read the article based on the Cardio and its related disease.I found this post very attractive as it contain very informative in nature.At our gym, all the fatties are constantly on the cardio equipment (you never see them doing anything else) while all the lean people are pushing weights, playing basketball, swimming, raquetball, or handball.

  13. Andrew S on November 3, 2009 at 05:33

    Is the “evidence of myocardial damage” evidence of myocardial damage, or evidence of muscle scavenging by a metabolism that has burned through its glycogen stores and hunting for more fuel? That’s one thing I’ve seen about the studies that show most post-marathoners showing signs of heart damage. It’s actually a sign of muscle breakdown; if you were looking at someone that just fell down while walking through the office, you’d say heart attack. Hence the association.

    Trudging along is definitely hateful. But running along a wooded trail in my VFFs isn’t trudging, and the ultramarathoners in Christopher McDougall’s _Born to Run_ don’t sound like they hate it. It seems to me most marathoners are scrawny, physically wasted, chronic-cardio addicts that adhere to the above-mentioned protestant ethic. That doesn’t mean that running a marathon is bad; it means those people are doing it for the wrong reasons.

    Is there a right reason? Dunno; just saying, the evidence here doesn’t seem to say running itself is bad. It says the way most people run is bad.

  14. Kurt G Harris MD on November 3, 2009 at 08:59

    Hi Andrew

    Late Gadolinium Enhancemant on MRI in the myocardium is a permanent scar -a heart attack – it has nothing whatever to do with any “scagenging”. Trust me on that.

    If “the way most people run” is hours at a time wihout a break, then I think we can at least say it does not prevent heart disease and may even be promoting it. The diet may well have lot to do with it as well.

    • Andrew S on November 3, 2009 at 11:03

      Thanks for the reply, Kurt. I just read your post at PaNu; I hadn’t realized that this LGE test was specific for myocardial damage. What I was remembering was some short-lived enzymes found immediately post-race that indicated muscle damage, and was assumed to be myocardial. LGE goes straight for the heart.

      From what I’ve seen of runners’ diets, they’re as horrible as the cyclists’ diets you’ve seen. Carb loading before runs, after runs, during runs, on days off, in the morning, afternoon, when they wake up in the middle of the night. Candy, soda, pasta, granola bars, junk junk junk. I used to love a weekend morning bagel; that place was always packed with runners.

      Hanging out with runners is painful. I feel like the vegetarian guy at the office; food choices are atrocious at any restaurant runners frequent.

  15. mattwel on November 3, 2009 at 11:41

    It’s an interesting article. I left a comment on Mr. Harris’ website, the gist of which was that hopefully people will wait for corroborating or disproving other data before changing their health regimen.

    He responded fairly tartly that I was a sheep, should work for the government, etc. It’s on his site, you can look at it if you like.

    I then tried to clarify my position a bit but he deleted my response. Then he banned me from his site. And turned on comment moderation to prevent, presumably, such alternate views as mine from ever being expressed in his sandbox.

    I am a bit flabbergasted by it all — shouldn’t the self-described iconoclastic and alternative be if anything unusually open to contrary viewpoints? It makes me wonder if such brittleness extends to his interpretations of data, with any that does not bolster his pet theories deleted and then banned from his mind.

    Anyway, my response was (with apologies for absent context:)

    Good lord, surely Mr. Gautama also has something reproachful to say about such angry outbursts. In any case my message was less to you than to those who had just read your post.
    Put too simply: In matters where we know little, fear of “being a sheep” can put one in greater danger than submitting to the consensus of experts. I did not mean to place the study you brought to our attention in such low company as known crazies like vaccine alarmists — they simply do an excellent job of illustrating my point.

    This is good data. Perhaps more will come to bolster it. Just as likely the opposite will happen, or these results will be attributed to a cause that will surprise us all and vindicate aerobic exercise in the process. So, given a choice between trusting my life to a single study from one set of doctors or the combined wisdom of the entire medical field, for me it’s not even close. By all means hurl more invective at me as a result.

    The above is a reconstruction from memory of the post you mysteriously deleted. Is no debate allowed here? Are all meant to kneel before you and lap up your wisdom uncritically? How very like a traditional doctor you turn out to be after all.

    • mattwel on November 3, 2009 at 14:10

      I just read Mr. Harris’ blog post on instituting comment moderation because of me. The comment that was deleted is listed above, but originally of course did not include the paragraph calling him a doctor (horrors,) as the context makes clear.

      It’s hard to see how it meets any of his criteria for deletion, and yet it was and me banned.

      Here is one I left on his post about moderation:

      Well, this doesn’t actually quite explain your deletion of my original post.

      After you had called me a sheep and implied I was a rube in a number of contexts, I simply suggested you were reacting with unnecessary anger. It wasn’t until you deleted that post that I brought out the doctor business.

      In any case, think about what you are saying: You get to be as gratuitously rude as you like to commenters, but they must be only respectful back to you — and that is when you allow their responses to stand at all. My first post met none of your criteria yet you deleted it anyway, presumably because you were irritated by my points.

      It is absolutely your site. You absolutely get to run it any way you like. The manner in which you do so will however affect your larger online reputation, and your particular approach strikes me as likely to get you known as a thin-skinned, easily-threatened bully.

      I will be curious to see if this gets posted. Either way, I know you have seen it, and that is something. Also: The post of mine you deleted here is alive and well on other sites, such is the nature of these internets.

      • Richard Nikoley on November 3, 2009 at 14:20

        OK, Matt, you got your say. Can we let it go now (at least here)?



      • mattwel on November 3, 2009 at 19:46

        Fair enough.

        Cool site, by the way. I have a lot of pictures of me going the other way.



  16. Aerobics & Cardio Man on November 5, 2009 at 07:30

    Interesting article. That is very true indeed!
    The exercising IS important for weight loss.

    By the way, congratulations for your success!

  17. Jocko on January 4, 2010 at 09:33

    We all need not forget that Pheidippides (The very first marathon runner) collapsed and died after delivering his message to Athens.

  18. David I on January 6, 2010 at 13:47

    Yes, Phedippides died after running from Marathon to Athens. But just before that he had run from Athens to Sparta and back to try and get the Spartans to come to the aid of Athens. That’s something in excess of 300 miles round trip. So I don’t think it was simply a matter of running a marathon that did him in. Running two back-to-back Spartathalons just before running a marathon might have had something to do with it.

    What I see all around me is that people tend to selectively look at studies that say the healthiest thing for them is to opt out of whatever kind of exercise they like least. (For the record, I train with weights, do Bikram Yoga, run distances, and do intervals. And I wouldn’t quit doing any of them.)

  19. Fred Hahn on March 18, 2010 at 05:59

    I’ve been saying this for years now. Dr. Eades and I discuss the danger of running in our book The Slow Burn Fitness Revolution. I also feel that a lowered RHR caused by chronic aerobic exercise is a sign of an unhealthy heart, not a healthy one.

    • Greg on September 15, 2010 at 12:08

      I’ve run 4 marathons and I can say that there’s no way it can be healthy… My body is completely over taxed and hurts so bad I’m barely able to walk afterward. I was signed up for my 5th this year until I read blogs here on FTA and Kurt Harris’ site. I have a half marathon in Philly this Sunday I’m thinking blowing off…. Now I’m lifting 4 times a week, eating as much protein as possible and liking it… instead of being a skinny little piss ant – I’m growing some muscles and having fun doing it.

Leave a Comment

You must be logged in to post a comment.