Joshua Denham and colleagues have published a study in PloS One showing that ultra-marathon running can help you to live longer by protecting your chromosomes.
Telomeres are DNA proteins that cap the end of your chromosomes to protect them. They become shorter with each cell division unless they are restored by an enzyme called telomerase. Unfortunately, most of our cells do not have enough telomerase to restore them completely, and eventually they become so short that the cell cannot divide anymore, becomes dysfunctional and dies.
Shorter telomeres are associated with numerous diseases and a higher mortality rate.
Scientists therefore consider their length as a measure of your biological age. It is determined by your genes (some of us are born with longer ones) and by the rate at which they are shortening.
Several studies have shown that a healthy lifestyle is associated with longer telomeres, probably by stimulating telomerase.
Most scientists agree that physical exercise is good for your telomeres, but they do not know what the optimal or safe amount is.
A study by Ludlow has suggested that very heavy physical activity is associated with shorter telomere length, just as a sedentary lifestyle is, while life-long moderate physical activity is linked to longer telomeres. This would mean that extreme endurance exercise is bad for you.
The telomeres of ultra-marathon runners
Joshua Denham and his colleagues examined the telomeres of 67 ultra-marathon runners and compared them with those of 56 healthy men of the same age. They noticed that the runners had significantly longer ones. Biologically the runners would be about 16.2 years younger than the more sedentary men, and the researchers concluded that ultra-endurance exercise can slow the aging of your cells down.
They also showed that this was independent of the traditional risk factors such as cholesterol, triglycerides and blood pressure.
Can I believe this?
Denham’s study is stronger than previous ones because it is bigger, the age range of the participants is larger and the runners perform a higher amount of aerobic exercise.
Just as the other ones, it is an observational study, which means that the scientists looked for an association between two findings, in this case endurance running and telomere length. It does not mean that one leads to the other, even though other studies have shown that endurance athletes live longer than the general population. It is possible that people born with longer telomeres are for some reason more likely to become endurance athletes. Based on these studies alone, there is no way that you can exclude this possibility.
Joshua Denham did not have any information about the diet and psychological stress of the participants. It has been proven that both factors influence telomere length, and you could easily imagine that ultra-marathon runners are much stricter with their nutrition than more sedentary people.
We obviously need more research to come to a definitive conclusion, but the difference between the ultra-runners and the others is so large that it has to make you think!
J Denham, C Nelson, B O’Brien et al. Longer leukocyte telomeres are associated with ultra-endurance exercise independent of cardiovascular risk factors. PloS One. 2013; 8(7): e69377 (accessed: 30/08/2013).
A Ludlow, J B Zimmerman, S Witkowski et al. Relationship between physical activity level, telomere length, and telomerase activity. Med Sci Sports Exerc. 2008; 40: 1764-1771.
M A Shammas. Telomeres, lifestyle, cancer, and aging. Curr Opin Clin Nutr Metab Care. 2011; 14(1): 28-34.