Periodic examinations of oxidative stress are a valid index for evaluating physical conditioning in Ekiden runners

Abstract

This study aimed to investigate whether periodic examinations of oxidative stress are a valid index for evaluating physical conditioning in Ekiden (long distance) runners. Twelve long distance runners (Mean age: 19.8±0.6 years, mean body weight: 54.5±5.0 kg, mean % fat: 5.5±1.8%) participated as subjects in this investigation. Oxidative stress (diacron reactive Oxygen Metabolites: d-ROMs levels) and antioxidant capacity (biological Anti-Oxidant Potential: BAP) were evaluated at the end of each month during a period of July to October, using the free radicals and reactive oxygen analyzer. Additionally, we estimated the BAP/d-ROMs ratio (B/R ratio) as a measure of oxidative balance. The total running distance during these 4 months was 2871.5±397.6 km (range: 2,166 km～3,437 km). The average running distance for the 12 runners in July, August, September, and October was 627.9±180.4 km, 771.4±145.6 km, 803.4± 106.4 km, and 668.8±81.5 km, respectively. With the decrease in the running distance from September through October, the mean monthly d-ROMs levels gradually decreased (p<0.05), but the mean monthly B/R ratio became higher (p<0.05). A significant positive correlation of 0.455 (p<0.01) was observed between the mean monthly running distance and the mean monthly d-ROMs levels; however, this correlation was not observed between the mean monthly running distance and the mean monthly BAP. Alternatively, a significant negative correlation of -0.450 (p<0.01) was observed between the mean monthly running distance and the mean monthly B/R ratio. The subjects participated in the Hakone Ekiden preliminary contest held on October and stood fourth. These results suggest that the periodic examinations of oxidative stress are a valid index for evaluating physical conditioning in Ekiden runners.