Telomere length and redox balance in master endurance runners: The role of nitric oxide.

Leukocyte telomere length (LTL), a biological marker of aging that is associated with age-related diseases, is longer in master endurance runners (ER) than age-matched controls, but the underlying mechanisms are poorly investigated. The LTL, nitric oxide (NO), and redox balance of ER master runners were analyzed and compared to untrained middle-aged and young adults. We hypothesized that NO and redox balance at baseline would be related to longer LTL in ER athletes. Participants (n = 38) were long-term ER runners (n = 10; 51.6 ± 5.2 yrs.; 28.4 ± 9.4 yrs. of experience) and untrained age-matched (n = 17; 46.6 ± 7.1 yrs) and young controls (n = 11; 21.8 ± 4.0 yrs). Volunteers were assessed for anamnesis, anthropometrics, and blood sampling. Measurements of pro-and anti-oxidant status and DNA extraction were performed using commercial kits. Relative LTL was determined with qPCR analyses (T/S). While the middle-aged controls had shorter LTL than the young group, no difference was observed between ER athletes and young participants. A large effect size between the LTL of ER athletes and middle-aged controls (d = 0.85) was also observed. The ER athletes and untrained young group had better redox balance according to antioxidant/pro-oxidant ratios compared to middle-aged untrained participants, which also had lower values for redox parameters (TEAC/TBARS, SOD/TBARS, and CAT/TBARS; all p < 0.05). Furthermore, the NO level of ER athletes (175.2 ± 31.9 μM) was higher (p < 0.05) than middle-aged controls (67.2 ± 23.3 μM) and young participants (129.2 ± 17.3 μM), with a significant correlation with LTL (r = 0.766; p = 0.02). In conclusion, ER runners have longer LTL than age-matched controls, which in turn may be related to better NO bioavailability and redox balance status.