Telomere shortening, a well-known biomarker of aging, is a complex process influenced by several intrinsic and lifestyle factors. Although habitual exercise may promote telomere length maintenance, extreme endurance exercise has been also associated with increased oxidative stress-presumed to be the major cause of telomere shortening. Therefore, the pace of telomere shortening with age may also depend on antioxidant system efficiency, which is, in part, genetically determined. In this study, we aimed to evaluate the impact of ultra-endurance exercise and oxidative stress susceptibility (determined by the rs4880 polymorphism in the superoxide dismutase 2 (SOD2) gene) on telomere length. Genomic DNA was obtained from 53 sedentary individuals (34 females, 19-67 yr) and 96 ultra-trail runners (31 females, 23-58 yr). Indeed, blood samples before and after finishing a 107-km-trail race were collected from 69 runners to measure c-reactive protein (CRP) levels and, thus, analyze whether acute inflammation response is modulated by the SOD2 rs4880 polymorphism. Our results revealed that telomere length was better preserved in ultra-trail runners compared with controls, especially in elderly runners who have been regularly training for many years. Carrying the SOD2 rs4880*A allele was significantly associated with having shorter telomeres, as well as with having increased CRP levels after the ultra-trail race. In conclusion, habitual ultra-endurance exercise had a beneficial effect on telomere length maintenance, especially at older ages. This study also suggested that the SOD2 rs4880 polymorphism may also have an impact on acute and chronic oxidative-related damage (inflammatory response and telomere length) after an ultra-trail race.NEW & NOTEWORTHY Habitual ultra-endurance exercise seems to promote telomere length maintenance, especially at older ages. In addition, the beneficial effect of ultra-endurance training on biological aging is higher in ultra-trail runners who have been engaged to ultra-endurance training during many years. Finally, and for the first time, this study shows that the SOD2 rs4880 polymorphism has a significant impact on telomere length, as well as on acute inflammatory response to a 107-km trail race.
Keywords: acute inflammatory response; oxidative stress; polymorphism; telomere; ultra-endurance training.