Objectives: The aim of the study was to evaluate the activity of xanthine oxidase (XO) in the blood of men and women during the first hour following a single anaerobic exercise (AN-EX), and after 24 hours of recovery, and to determine whether the changes in XO activity in the blood after AN-EX are dependent on anaerobic performance.
Methods: Ten men and ten women performed a single AN-EX. Blood was collected before and five times after completion of the AN-EX. The activity of XO was determined.
Results: In both groups, a significant (P < 0.05) increase in blood XO activity was found only 24 hours after the AN-EX. The increased activity of XO in men was significantly lower than in women (P < 0.05). Negative correlations were found between the increase in XO activity in the blood plasma 24 hours after the AN-EX and anaerobic power, the total work performed during the AN-EX and the power decrease.
Discussion: In the first hour after the single AN-EX, XO activity in the blood of women and men did not change, but after 24 hours of recovery, it was significantly higher compared to baseline levels in both sexes. Single AN-EX causes a smaller increase in XO activity in people with higher anaerobic performance.
Keywords: Xanthine oxidase; anaerobic exercise; muscle injuries; oxidative stress; sex differences.