Too many marathons very bad for you!

Krusty_Clown wrote: »

Interesting that their expert panel of cardiologists are from Kansas City, Missouri, where they have one of the highest rates of obesity in the United States (and by that logic one of the highest obesity rates in the world). Which do you think poses a greater health risk; running too many marathons, or obesity? I think they have their priorities wrong.

Extract wrote:

Run for your life … at a comfortable speed and not too far

James H O'Keefe1,2, Carl J Lavie3,4
+ Author Affiliations

1Saint Luke's Mid America Heart Institute, Kansas City, Missouri, USA
2University Of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
3Department of Cardiology, John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine, New Orleans, Louisiana, USA
4Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
Correspondence to
Dr James H O'Keefe, Saint Luke's Mid America Heart Institute,4330 Wornall Road, Suite 2000 Kansas City, MO 64111 phone: 816-751-8480 fax: 816-756-3645 jokeefe@saint-lukes.org
During the Greco-Persian War in 490 BCE, Phidippides, a 40-year-old herald messenger (professional running-courier) ran the 26 miles from a battlefield near Marathon, Greece, into Athens carrying momentous news of Greek victory. Upon arriving at the Acropolis, he proclaimed: ‘Joy, we have won!’ and then immediately collapsed and died.1 Fast-forward about 2500 years to an era when the baby-boomer's came of age and long-distance running boomed. The prevailing logic held that aerobic exercise is clearly good for one's health and that, if some is good, more must be better. In 1975, Dr Thomas Bassler, a physician/runner, boldly proclaimed that, if you could run a marathon, you were immune to death from coronary heart disease (CHD).2 This urban myth has long since been disproven; indeed an emerging body of evidence suggests the opposite: extreme endurance exercise may exact a toll on cardiovascular (CV) health.

‘Show me the bodies’
After our recent articles on this topic,1 ,3–5 Amby Burfoot, winner of the 1968 Boston Marathon and Editor-at-Large for Runner's World Magazine, challenged our assertions about the dangers of extreme endurance efforts by demanding, ‘Show me the bodies’. Amby has a good point: the risk of dropping dead in a marathon is remote, about 0.5 to 1 in 100,000 participants.6 But the occasional marathoner or triathlete who dies while strenuously exercising is the ‘canary in the coal mine’. Chronic extreme exercise appears to cause excessive ‘wear-and-tear’ on the heart, inducing adverse structural and electrical remodelling, which offsets some of the CV benefits and longevity improvements conferred by moderate physical activity. Thus, even though chronic extreme exercise may not kill you, it may erase many of the health advantages of regular moderate exercise.

Indeed, regular vigorous exercise is probably the single best step a person can take to ensure robust CV health. In a …

nerraw1111 wrote: »

To be fair, Crossfit is a fad, given it's fairly new and has an almost like religious following.

Same with the obstacle races, they can be considered a fad. Not necessarily a disparaging remark.

However, if a group connected with Crossfit is putting out ‘dodgy research’ about marathon running, it needs to be questioned. It does seem to be fatally flawed according to Runner’s World article.

wrote:

There is now convincing evidence that repeatedly asking the heart to pump “massive” volumes of blood, for hours at a time, can lead to an array of problems, they say.

In a study of 416 000 adults followed for a mean of 8 years, 40–50 min per day of vigorous exercise reduced risk of death by about 40% (figure 1).7 In that study, at about 45 min, a point of diminishing returns is reached whereby longer exercise efforts do not appear to translate into lower death risk.

A trial randomised 60 male patients with CHD to vigorous exercise sessions of either 30 or 60 min.11 The 30 min exercise workouts improved arterial elasticity and produced minimal oxidant stress. In contrast, the 60 min sessions increased oxidant stress and worsened vascular stiffness as measured by pulse wave velocity, particularly in those over the age of 50. MRI scans of runners who have been participating in marathons for decades show a threefold increased incidence of scattered fibrosis and scarring in the walls of the atria, interventricular septum and RV (figure 3).12 Cardiologists from Minnesota evaluated a group of runners who had completed at least 25 marathons over 25 years and found a 60% increase in coronary plaque burden compared with sedentary age-matched controls.1 These findings were replicated by a group from Germany, who showed increased coronary plaque in 108 chronic marathoners compared with sedentary controls.13 This scarring can set the stage for dangerous heart rhythms, such as atrial fibrillation, which is increased approximately fivefold in veteran endurance athletes.10 Ventricular tachycardia and sudden cardiac arrest can also be seen in endurance athletes even in the absence of CHD and hypertrophic cardiomyopathy.

Two very recent studies presented in abstract form at major national meetings may revolutionise our thinking about running and its health effects.16 ,17 One is a prospective observational study that followed 52 600 people for up to three decades.17 The 14 000 runners in that study had a 19% lower risk of death compared with the 42 000 non-runners. Yet, when they sub-grouped the runners by weekly mileage, those who ran over 20 or 25 miles per week seemed to lose their survival advantage over the non-runners (figure 4). On the other hand, those who ran between 5 and 20 miles total per week enjoyed a 25% decrease in risk of death during follow-up. The same pattern emerged for speed of running: the fast runners, those running typically over 8 miles an hour, appeared to get no mortality benefit compared with the non-runners, whereas those who fared best usually ran about 6–7 miles per hour—a comfortable jog for most people. In addition, the individuals who ran 6 or 7 days per week appeared to lose the mortality benefits, whereas the survival advantages accrued best for those who ran 2–5 days per week.

Conclusion

The take home message for most is to limit one's vigorous exercise to 30–50 min/day. If one really wants to do a marathon or full-distance triathlon etc, it may be best to do just one or a few and then proceed to safer and healthier exercise patterns. On the other hand, light or moderate intensity exercise does not present the dose-dependent risks associated with excessive endurance exercise. A routine of moderate physical activity will add life to your years, as well as years to your life. In contrast, running too fast, too far, and for too many years may speed one's progress towards the finish line of life.

Krusty_Clown wrote: »

I did not say it was relevant to their study. I said they would be better off focusing their efforts on problems that are more prevalent. To quote their statistics, this issue affects 1 in 100,000 marathon participants. Let's very generously assume that 20% of Americans have completed a marathon (though I suspect the actual figure would be less than 10%). So, based on these quite generous numbers, this issue could possibly affect 1 out of every 500,000 Americans. At what point does something stop being statistically relevant and become mere coincidence? A similar number of Americans are killed falling out of bed every year (approximately 600). Perhaps the subject for another study, in which the recommendations might be that everyone should sleep on the floor, or avoid getting out of bed altogether?

Lets briefly discuss the counter-argument; how many people have taken up exercise in order to complete a marathon? How many have given up smoking (which kills 443,000 Americans every year)? How many have returned from an obese state (which kills 300,000 Americans every year)? How many people's lives have been prolonged, because they set themselves the goal of completing a marathon? You think that figure would be greater than 1 in every 500,000 Americans? So do I.

Krusty_Clown wrote: »

The article holds up Caballo Blanco as an example to substantiate their argument. The guy lived with the Tarahumara Indians, surviving on a diet of berries, peyote and cactus-brewed alcohol. He died at age 58, living among a people whose average life expectancy is 45 years. Sounds like a success story to me!