When James Fixx died at the age of 52 on July 20th, 1984, in the middle of his daily run, it was a huge shock to runners, athletes and fitness buffs. When Fixx was 35 he weighed 240 pounds and smoked a couple of packs of cigarettes a day. He was about as fit as a potato.

A decade later he was the poster child for fitness. He had lost 60 pounds, had stopped smoking and his book, The Complete Book of Running, was an internationally acclaimed million-copy best seller. James Fixx had become a long-distance runner and a role model for people who wanted to get serious about exercise and improve their health. That’s why his death came as such a shock. Someone who had turned his life around so completely with a healthy lifestyle should have been able to dodge a deadly heart attack.

Experts tried to explain away the premature death on genetic grounds (Fixx’s father had a heart attack and died when he was 43). Then there was the history of smoking and the overweight problem. What no one ever considered was running itself.

It will come as a huge shock to most people to learn that marathon runners may actually have more heart problems than less intense exercisers or perhaps even people who have a sedentary life style. A fascinating article in The Wall Street Journal titled “Why You Shouldn’t Eat and Run” summed up a recent study:

“A study published in the current edition of Missouri Medicine found that 50 men who had run at least one marathon a year for 25 years had higher levels of coronary-artery plaque than a control group of sedentary men.”

A recent study in BMJ analyzed the risk of atherosclerosis in the carotid arteries of 42 Boston marathoners. The researchers compared the thickness of the arteries in their necks with those of their less athletic spouses. The results were surprising:

 “This study was, to our knowledge, the first to assess cardiovascular risk biomarkers in trained runners versus their domestic partners to minimise the influence of lifestyle differences on the effects of chronic, high-intensity exercise. Many aspects of the cardiovascular profile were better in runners versus controls, and age and Framingham risk scores were directly related to cIMT [carotid intima-medial thickness], but cIMT did not differ between runners and controls. These results suggest that chronic endurance training improves cardiovascular risk parameters, but does not retard the progression of carotid atherosclerosis.”

Clearly, running a marathon does improve cardiovascular fitness. Surprisingly, it does not seem to have an impact on atherosclerosis or clogging of arteries. The Wall Street Journal sums up the research thusly:

“A small body of research suggests that heart problems may arise not in spite of extreme-endurance exercise but because of it. That has led some cardiologists to theorize that, beyond a certain point, exercise stops preventing and starts causing heart disease.”


What is the take home message? Please do NOT use this preliminary data to discourage you from exercising. Clearly, moving your body is good for your heart, your brain and just about every cell in your body. But do not expect intense exercise such as marathons or triathlons to protect your arteries or help you avoid a heart attack. Moderation in all things, including exercise, may be the key to optimum health.

Share your thoughts about exercise below.

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  1. Michael

    When your body is “fighting” anything, even a cold, it needs a lot of energy for repair and replacement, not for sports activities.

  2. cpmt

    I read somewhere (cancer articles) that doing excess exercise doesn’t help the person fighting the cancer. They -scientist- recommend exercise in moderation and the best is walking and swimming.

  3. Jen

    One critical aspect of Jim Fisk that is not mentioned in any of this is his joie de vivre which he experienced in his own life and which he spread to all who read his book and his articles. Who knows why he died so young. But people like Jim Fisk are a blessing to all whose lives are touched. Badmouthing his love – and that of others – for running makes no sense.

  4. Mike

    I read about this a while back on Dr. Mercola’s web site. Short high intensity with a lower intensity break seems to be the ticket.

  5. DM

    You shouldn’t have used “intense exercise” in your title. High intensity exercise (HIT) doesn’t increase heart problems, it is protective. People need to understand the difference.

  6. alexis jones

    would like to receive comments. Thanks.

  7. emb

    Very interesting article and comments generated also. I have been running 5K every other day for about 10 yrs now, I am 58 yrs old. Moderation is the key to many things, and running falls into that category for me. I have no desire to ever run a marathon, I find it almost inhuman to push your body to run 26.2 miles at once. I just don’t feel our bodies were meant to do that, and many runners I know feel the same way. I certainly hope my little 5K jaunts will continue to keep me healthy both inside and out, as I feel really good both during and after my runs.

  8. st

    The man who died running the marathon had already damaged his arteries and maybe his heart. Anyone who loses a lot of weight should have a stress test done before undergoing strenuous prolonged exercise. My son had a heart attack in his young 30’s and is thin. He comes from a family with heredity heart disease. This would also happen to Gov Christie considering the amount of weight he has lost so far. It is estimated he has lost 100 lbs and is still considered obese. He is under a doctor’s care.

  9. RES

    My. Husband & I stayed in Italy for a month—-living in a house in a small town. We have seen statistics ranking Italy as near the top for longevity——-& we saw the villagers WALKING EVERYDAY & EVERYWHERE. Their diet consists of pasta—-bread. …..olive oil…..garlic….& wine. SO GO FIGURE!!!!!!

  10. Mary

    Al Sears, MD, has been stating for years that shorter duration (about 12 minutes), more intense exercise increases lung capacity and the ability of the heart to respond.
    You can start with minimal exercise and work up.
    Dr. Sears also says that statin drugs restrict the ability of the heart to respond to physical challenges where a faster heartbeat is necessary.
    Not a good thing at all.

  11. Noah V.

    Does anyone consider that it has nothing to do with either genetics or exercise but that these running-obsessed individuals did not properly watch their diets, figuring that all their running not only burnt off excess calories but also the toxic elements in what they ate?
    We too often think that looking good (thin?) on the outside means you look good on the inside too. Uh uh.

  12. Maria

    Given that endurance athletes practice “carbo loading” could the study be witnessing the deleterious effect of high carbohydrate, in this case, very high carbohydrate diets on blood lipids?

  13. DS

    Runners were big on carb-loading, following the low fat diet advice of doctors, and avoiding saturated fats and trying to keep their cholesterol low. They probably used a lot of sunscreen, avoiding vitamin d In the process, and they did not take vitamin k2. They probably also avoided salt and drank lots of water with no salt in it. I agree that moderation is best, but the diet advice they received was deadly.

  14. cpmt

    I know of several people *(4) who died of a heart attack doing exercise (running every morning). None of them had heart problems, it seems.

  15. cpmt

    we are obsessed with extreme exercises for normal people… middle age, old, etc.. and the body is not made for that. For centuries and today in other places (many third world) walk everywhere and live 100 years. Take their time, rest, talk to other every day in a relaxing set up. etc etc…
    I do not believe that been ‘borregos’ (followers to every fad on earth) helps much. Some things are worth to follow… but not everything specially went it comes to our bodies. If you have cancer you should do some easy – not exhorting or strong – exercise, nor if you have problems with other parts of the body.
    A GOOD DIET it is important, but with common sense, don’t believe everything you see or hear. this is my opinion.

  16. mbc

    This information is not surprising at all but I am glad it has been focused on once again. Too often those who exercise rely on their fitness level to be an overall indicator of their health and life expectancy. What we eat and put into our body each day along with rest and lifestyle choices all work together. I remember when Jim Fisk passed away because I had his book at that time and was running almost daily.
    My father died young of a heart attack as well and he had also struggled with obesity as an adult. Fisk’s story touched me and even gave me a wake up call. After running 2 marathons I know that running gives me something that I love, adrenaline! But my overall health seems to improve when I rest well and eat well, which is no surprise.

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