As I was reading the March issue of IDEA fitness journal, I came across another research about endurance exercise linked to heart damage risk. Of course, this is not the 1st study or research which shows that endurance exercise or training is closely linked to increase risk of damaging the heart, thus, heart failure at one point.
I've told many of my friends and colleagues about endurance types of exercises, sports or training, could lead to scarring of the heart muscles, in other words, fibrosis. Recently, couple of world class soccer players suffered heart attack @ cardiac arrest during the game on the pitch. One is fortunate enough to see the light again, but the other Italian player, was not so lucky and died. I'm sure many people would have asked, "Aren't soccer players fit and healthy?" Well, being fit probably yes, but healthy in sense of heart health? I'm not too sure about that depending on the training intensity and frequency as well as other factors which may contribute to the 'ticking timebomb'.
I remembered talking to a trainer, who is C.S.C.S, about almost half year ago. I asked him, "Why do we see many cases of marathon runners suffered heart attack?" He said, "It's random case, most likely the athelete has underlying heart condition". Well, most personal trainers studied cardiovascular system and fitness, how endurance exercise or training affect the cardiovascular system, range of heart rate levels, how capilarries grow overtime and improved V02MAX after a consistent chronic period of endurance exercises or training. But, the question is, most certified personal trainers have insufficient knowledge and understanding of how endocrine system would affect the autonomic nervous system and the heart, particularly glucocorticoids hormones. Of course, I'm talking about chronic endurance physical stress impacting the hormonal pathway of an individual. Training 10-20km run regularly, participating in trialthon competitions dozen of times yearly, long distance cycling, etc. It doesn't matter what type of training or movement or sports, as long as chronic endurance long duration physical stress, glucocorticoids hormones are pouring out like there is no tomorrow, apart from muscle wasting, the levels of blood clotting factors are elevated (such as fibrinogen) and causing heart muscle scarring and imbalance heart ventricle muscles.
Most people are gearing up to train for marathons and long distance cycling, but do they actually know the affects of the heart and overall health? How many would listen and do their own research? Anyway, let's cut to the chase, and I will share with you and to those who is into endurance exercises or training, below is the latest researches from Australia and Belgium extracted from European Heart Journal 2011. Meanwhile, I also attach an article by European Society of Cardiology which mentioned the problems associated with atrial fibrillation for endurance athletes. A study conducted by Dr Luis Mont from the Hospital Clínic de Barcelona, Spain.
By Ryan Halvorson
"Several reports have emerged over the past few years linking endurance exercise with heart problems. Most recently, researchers from Australia and Belgium studied 40 trained athletes who were to participate in one of four events. Endurance trialthon, alpine cycling, an ultra trialthon or marathon. The athletes presented with no known heart problems. The researches obtained magnetic resonance imaging (MRI) from each athlete 2-3 weeks before the race, 1 hour postrace, and 6-11 days postrace.
When examining the results, the researchers noted that 1 hour after the race, the athletes right ventricles had changed shape, volume had increased and function had decreased. Fortunately, in most of the subjects heart shape and functions returned to prerace condition after a week. However, the five athletes with the most experience in endurance racing presented with more permanent scarring.
Intense endurance exercise causes acute dsyfunction of the right ventricle, but not the left ventricle. Although short term recovery appears complete, chronic structural changes and reduced right ventricle function are evident in some of the most practiced athletes, the long term clinical significance of which warrants further study."
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"Three papers presented at this congress by Dr Mont's group reflect the research effort now being directed towards sports cardiology and the prevention and treatment of rhythm disorders.
1.Efficacy of the circumferential pulmonary vein ablation of atrial fibrillation in endurance athletes. CPVA is a recently introduced technique which identifies the signals causing the atrial fibrillation and isolates their source in the pulmonary veins from the left ventricle of the heart. The technique has been successfully used in routine patients with atrial fibrillation and, according to new data presented here in Berlin, is now as effective in AF secondary to endurance sports as in other causes. A series of 182 patients in Dr Mont's Barcelona clinic found that freedom of arrhythmias following CPVA was similar in the sports participants as in the regular patients. Left atrial size and long-standing atrial fibrillation were the only independent predictors for arrhythmia recurrence after the treatment, not sports participation.
2.Deconditioning reverses expression of cardiac fibrosis markers in an animal model of endurance training. A more basic science study from Dr Mont's group in Barcelona also suggests that those with a history of arrhythmias following endurance training may benefit from a period of "deconditioning" following their efforts. The suggestion follows a study in animal models which found that markers of cardiac fibrosis in rats whose treadmill exercise was followed by a period of inactivity returned to control levels. Endurance exercise causes cardiac structural changes, including atrial and right ventricular fibrosis - and this fibrosis may play a role in the development of arrhythmias. Although it has been noted that the athlete's heart regresses after inactivity it is not known if the sport-induced atrial and right ventricular fibrosis also reverses after deconditioning. This study suggests that it does and that a period of inactivity might be of benefit in those with a history of fibrillation.
3.Losartan attenuates heart fibrosis induced by chronic endurance training in an animal model. Just as inactivity after training may inhibit cardiac fibrosis in animal models, a similar study suggests that the anti-hypertensive drug losartan prevents the heart fibrosis induced by endurance exercise. The anti-fibrotic effect of losartan, an angiotensin type-II receptor antagonist, appears to be mediated suppression of angiotensin II-induced proliferation of fibroblasts. Again, markers of fibrosis were reduced by administration of losartan."
-European Heart Journal (2011; doi:10.1093/eurheartj/ehr397)
-European Society of Cardiology, The European Heart House 2035 Route des Colles, B.P. 179 - Les Templiers, Sophia Antipolis F-06903 France
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