Background and Objectives: Because of its stimulant effects, caffeine has long enjoyed wide acceptance among the various strata of the society. This study aims to determine the effect of short-term caffeine supplementation on some of antioxidant (GPx and SOD) and lipid peroxidation (MDA) indices responses in serum active men after one-session aerobic exercise.

Materials and Methods: Twenty active males (mean age 25±3 years, body fat 13±2% and VO2max 52±4 ml/kg^-1/min) into a experimental, randomized and double-blind design were divided in two homogeneous supplement and placebo groups (5 mg.kg^-1.day Caffeine or Dextrose). After 14 days of supplementation, all subjects were participated in the aerobic exercise protocol (running on the treadmill at the -15% incline for 30 min with 65% VO2max). Blood samples were taken at three phases (baseline, after supplementation period and immediately after the exercise). Data were analyzed by repeated measure ANOVA, Bonferroni and independent t-test at α≤0.05.

Results: The results showed that the 14-days caffeine intake had significant effect on the basal antioxidative enzymes (GPx and SOD)  capacity (P≤0.05). Moreover, 30 min aerobic exercise significantly reduced antioxidative power (P≤0.05) and significantly increased in the oxidative stress markers (MDA) (P≤0.05). However, increased levels of oxidative stress markers in the placebo group were significantly more than in the caffeine group (P≤0.05).

Conclusion: Our results suggest that the increased basal antioxidative capacity (GPx and SOD) following caffeine supplementation can decrease the undesirable alterations of exercise-induced oxidative damage (MDA) in active males.

Keywords: Caffeine, Aerobic exercise, Oxidative stress