Objective: To evaluate the effect of six weeks of high intensity interval training (HIIT) and L-Arginine supplementation on interleukin-6 (IL-6) levels and body composition in Iranian adult trained males.
Methods: This experimental study was performed as an intervention with a pretest-posttest design in three experimental groups and one control group. Fortyeight young males from Qazvin province (Iran) were selected voluntarily based on convenience sampling. Participants were randomly divided into four groups (12 participants in each group): "HIIT"; "L-Arginine supplementation"; "HIIT + L-Arginine supplementation", and "HIIT + placebo". At 7 a.m., when the level of inflammation was at its lowest, a blood sample was taken from the participants, and body mass index (BMI), body fat percentage (BFP), and lean body mass (LBM) were determined. IL-6 analysis was performed using STATE FAX device and ELISA method. Training sessions were conducted for six consecutive weeks, three sessions a week. Analysis of covariance and Bonferroni post hoc test were used to analyze the data.
Results: i) There were no significant differences between groups in BMI, BFP, or LBM. ii) There was a significant difference in IL-6 levels between the groups (p < 0.05), so that the inflammatory levels in the "HIIT + L-Arginine supplementation" and "HIIT + placebo" groups were lesser than the "HIIT" (0.002 and <0.001, respectively) and "L-Arginine supplementation" (<0.001and <0.001, respectively) groups. HIIT "seems" to reduce the level of inflammation.
Conclusion: HIIT had no significant effect on body composition indices. Plasma IL-6 levels decreased after six weeks of HIIT and L-Arginine supplementation. The level of IL-6 in the "HIIT + L-Arginine supplementation" and "HIIT + placebo" groups were lower than the control group (i.e.; "HIIT") and supplement control group (i.e.; "L-Arginine supplementation").