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Scarring on the Heart in Male Triathletes
Men who regularly participate in triathlons have an increased risk of developing scar tissue on the heart.
Scar Tissue on the Heart
Men who participate in triathlons have a higher risk of the potentially harmful condition where scars (fibrosis) form on the heart muscle (myocardial fibrosis). This is the outcome of research that will be presented next week at the annual meeting of the Radiological Society of North America (RSNA) [1]. This increased risk, not observed in women, is associated with the amount of training.
This scarring often occurs in the heart chambers (ventricles). In severe cases, this can lead to heart failure. Although regular exercise is good for the cardiovascular system, previous studies have also found fibrosis in the hearts of elite athletes.
According to lead author of the study, Jitka Starekova, M.D. from UMC Hamburg-Eppendorf, the exact consequences of this are still unclear. “However, they might be a foundation for future heart failure and arrhythmia.”
Dr. Starekova and colleagues examined a group of 55 male (average age 44) and 30 female triathletes (average age 43). The athletes’ hearts were examined using MRI and the contrast agent gadolinium. Gadolinium is absorbed by both healthy tissue and scar tissue. However, it disappears more quickly from normal tissue than from scar tissue, creating a contrast between the two tissues after about 10 minutes. A useful tool for detecting any scar tissue.
Difference Between Male and Female Triathletes
Fibrosis was found in the left ventricle (responsible for pumping oxygenated blood to the body) in 10 out of 55 men. In women, however, this was not found in any case.
The athletes in whom scar tissue was found in the heart were also the athletes who ran, cycled, and swam significantly longer distances. Additionally, the (peak) systolic blood pressure (upper pressure) was higher in this group.
Women had lower upper pressure during maximum exertion than men. Their sports history also showed that women often participated in races of shorter distances than men. Men had significantly more participation in Iron Man (3.8 km swimming, 42.2 km running, 180 km cycling) and half Iron Man in their lifetime than women. From this, the researchers conclude that there is a direct link between the level of training, blood pressure, and the risk of scarring.
According to Dr. Starekova, this could have several causes. Higher upper pressure can result in a larger mass of heart muscle, while high levels of exertion can cause inflammation. These conditions, combined with repeated stress on the left ventricle due to exertion, can damage the heart muscle. The researchers also consider that the difference in risk between men and women may be caused by factors other than those currently demonstrated. For example, differences in testosterone levels.
Although we cannot prove the exact mechanism for the development of myocardial fibrosis in triathletes, increased systolic blood pressure during exercise, the amount and extent of race distances and unnoticed myocarditis could be cofactors in the genesis of the condition. In other words, repetition of any extreme athletic activity may not be beneficial for everyone.
The fact that repeated ‘extreme’ athletic activities may not be healthy for everyone may not be entirely surprising. However, it is helpful to know how, when, and in whom this may manifest. The researchers aim to find out in long-term follow-up studies whether athletes with such scarring have also had heart conditions such as heart attacks.
References
- rsna.org/news.aspx?id=23245
