Effects of extreme mountain ultramarathon on stress-related biomarkers from multiple biological matrices in adult male runners.

Prior investigations concerning finishers of the Tor des Géants (TDG) have demonstrated oxi-inflammatory response. MicroRNAs (miRNAs) have been identified as prospective biomarkers for oxi-inflammatory and stress responses. This study addressed the acute responses concerning salivary miRNAs, circulating redox markers and urinary exercise-induced markers during the 2019 TDG. It included seven healthy male participants who successfully completed the race. Biological specimens (blood, saliva, and urine) were collected 1-2 days prior to the race and immediately post-completion, to assess redox system and glycemia from capillary blood, creatinine and neopterin concentrations from urine, and salivary hsa-miR-210 and hsa-miR-21. Circulating reactive oxygen species production increased, whereas total antioxidant capacity remained stable. Urinary creatinine and neopterin increased subsequent to the race. Nevertheless, salivary expression levels for both miR-21 and miR-210 displayed heterogeneity among participants. Variations in miR-210 were significantly correlated with changes in heart rate. The extreme mountain ultramarathon incited cumulative stress reflective of muscle damage and immune response activation. Salivary miR-21 and miR-210 did not demonstrate acute alterations, indicating that they may not serve as highly responsive markers for the combined hypoxia-strenuous exercise stressor; this finding may suggest the existence of adaptive mechanisms in finishers that facilitate their capacity to manage extreme challenges.