Thursday, June 14, 2012


For the less well read amongst us I would like to point out that the Mayo Clinic is not a hospital that deals with patients who eat too much mayonaise !........(at least I don't think it is). However, I believe that for  the benefit of endurance athletes worldwide perhaps it is only correct to bring this alarming new study  by the Mayo Clinic to everyone's attention.

 I will try to  analyse the link above as best I can but for those who want the full information I suggest reading the whole study........its fascinating stuff.
                           Simply put, too much endurance running will kill you !
  Its quite technical but the main thrust of the findings are that there is an increased risk of Atrial Dysfunction due to Atrial Fibrillation (AF). Endurance athletes are aware that changes in the structure of the heart, arteries, general physyology and many other mechanical mechanisms ( muscles, joints, etc) do occur during consistent endurance training. Without these adaptations it would be virtually impossible to run long distances and for many hours. Many of these adaptations provide enourmous health benefits in ways too numerous to mention but the Mayo clinic's study has highlighted an area of specific concern to all endurance athletes.

Long-term excessive endurance exercise may induce

pathologic structural remodeling of the heart and large arteries. Emerging data suggest that chronic training for and

competing in extreme endurance events can cause transient acute volume overload of the atria and right ventricle, with transient

reductions in right ventricular ejection fraction and elevations of cardiac biomarkers, all of which return to normal

within 1 week. Over months to years of repetitive injury, this process, in some individuals, may lead to patchy

myocardial fibrosis, particularly in the atria, interventricular septum, and right ventricle, creating a substrate for atrial

and ventricular arrhythmias. Additionally, long-term excessive sustained exercise may be associated with coronary

artery calcification, diastolic dysfunction, and large-artery wall stiffening.

      The result being an irregular pulse which can lead to blood stagnation, embolism and risk of a stroke and this reduction of cardiac output (especially during exercise) can lead to heart failure......Crikey! its all serious stuff. There can be up  a 5 fold increase in AF in endurance athletes. Cardiac remodelling has been known for sometime and the effects were thought to be benign but this new study says not, even after endurance training is finished. It shows that up to an hour of exercise is very good for you but after this the benefits tail off . Oxidative stress has been known for many years in endurance runners but its the effects of this in relation to AF that raises the main concerns. It is noted that these issues will still only effect a small percentage of endurance athletes but the point is there is a risk.
       The funding for this study was apparently commissioned by Coca Cola but although I am not a fan I don't think there is any slant (as in the 'run less and drink more coke' idea ) besides Coke makes drinks used by endurance athletes and many use it whilst running. To do what you may ask? If athletes are tired the caffeine and sugar in coke gives them a lift and stimulates the heart.......Okay, now Iam really confused. Coke commissions a study that says endurance running is bad for you and then supplies endurance athletes with Coke and Gatorade so as to stimulate the heart and make them run faster !!!! Go figure. Capitalism is not dead.
      In conclusion I believe the study raises some very serious issues and perhaps blood and heart tests may be a good idea for all. I love running through the mountains and it would be sad to think that the healthy life affirming thing we all do could actually be to our detriment.