The acute effects of exhaustive resistance training and different dosages of caffeine intake on IL-6 response

Based on the limited and inconsistent results about the effects of acute methylxanthine component on exercise-induced inflammatory response, the present study was conducted to identify the effect of acute different doses of caffeine intake on serum interleukin-6 (IL-6) response in male volleyball players following one-session of exhaustive resistance exercise. Thirty male volleyball players (aged 21.47±1.45 years, fat 10.47±3.11%, and BMI 23.15±1.26 kg.m2) in a quasi-experimental, randomized and double-blind design were allocated equally into three randomized groups: supplement groups (Caffeine intake: 6 or 9 mg.kg-1) and placebo group (Dextrose intake: 6 mg.kg-1). About 45 min after the supplementation subjects were participated in a one-session resistance weight-exercise (7 stations in 3 sets per station with 80% of one repetition maximum until exhaustive). Changes in inflammatory index (serum IL-6) were determined in three phases (baseline, 45 min after the supplementation (before exercise) and immediately post-exercise protocol).The normal data were analyzed by repeated measure ANOVA and Bonferroni at α≤0.05. The results show that the acute ingested caffeine doses of 6 and 9 mg-1 has significant effect (p≤0.05) on the basal changes in serum IL-6. Moreover, both ingested caffeine dosages of 6 and 9 mg-1 in interaction with the resistance exercise worsened the inflammatory indices as compared to placebo group (p≤0.05). Based on the present results, it can be concluded that acute different doses of caffeine intake at baseline induces low grade inflammation (increase in the serum IL-6) and also cannot decrease the undesirable inflammatory indices response induced by one-session of resistance exercise in male volleyball players.