Racial Variation of Interleukin-6 in Soccer Players: The Effect of Short-Term Maximal Exercise

Inflammation is a common pathophysiological pathway for a number of chronic diseases. This study examined the effects of time-of-day and race on soccer players’ plasma concentration of interleukin-6 (IL-6) during short-term maximal exercise. 36 soccer players were divided in three groups (i.e., 12 black Tunisian (BT), 12 white Tunisian (WT), and 12 south African (SA)) and performed a 30-s Wingate test at 08:00 and 18:00 h during which the peak (P peak) and mean (P mean) powers and the fatigue index (FI) were assessed. Moreover, plasma interleukin-6 (IL-6) concentrations were measured before (P1) and immediately (P2) and 60 min (P3) after the exercise. Our results showed that oral temperature, P peak and P mean were significantly higher (p < 0.001) in the afternoon than in the morning and considerably more so in SA than in WT and BT (p < 0.05). However, no major difference was observed between WT and BT in regards to all parameters. Likewise, plasma concentration of IL-6 were significantly higher (P