The short-term effect of caffeine supplementation on immune-endocrine responses to acute intensive exercise

Abstract

Summary Introduction The short-term supplementation of caffeine with physical exercise is effective on the homeostasis of the immune system and hormones. The purpose of this study was to investigate the consumption of caffeine supplementation on immune-endocrine responses following one session of intense exercise. Method Sixteen male students (weight 65.4 ± 4.40 kg and age 23-27 years) participated in this study. After matching, the subjects were randomly divided into two groups of caffeine supplementation (n = 8) and placebo group (n = 8). The placebo group, dextrose and experimental group received caffeine supplementation (6 mg/kg) and participated in a 90-minute exercise of pedaling on a bicycle ergometer at 70% VO2max. Blood samples (neutrophils, lymphocytes, monocytes, cortisol, and Interleukin-6) measured in three steps, before supplementation, immediately after exercise, and one hour later. The interactions of group versus time were Analysis of Variance (ANOVA) for repeated measures followed by Post hoc Bonferroni test. Results Caffeine supplementation significantly increased the monocytes in 1 hour posttest (P = 0.023), the neutrophils in immediately posttest (P = 0.032) and 1 hour posttest (P = 0.026), and the cortisol in 1 hour posttest (P = 0.020) compared to the placebo group. There were significant differences between the two groups in terms of the examination of white blood cells at different times. Levels of IL-6 increased in the supplementation of caffeine in immediately post test (P = 0.003) and 1 hour post test (P = 0.001), which this increase was more than placebo group. Conclusion It seems that caffeine supplementation with acute severe exercise can be stressful for short-term fitness adaptation. Because in this study it was observed, the use of caffeine in acute severe exercise led to an increase immune-inflammatory responses and slowdown the reduction of cortisol catabolic hormones. However, further studies are needed.