Effect of acute maximal exercise on circulating levels of interleukin-12 during Ramadan fasting

The purpose of this study was to examine the effects of Ramadan fasting on circulating levels of interleukin-12 [IL-12] after a brief maximal exercise. Nine subjects performed a Wingate test on three different occasions: [i] the first week of Ramadan [1WR], [ii] the fourth week of Ramadan [4WR], and [iii] three weeks after Ramadan [AR]. Blood samples were taken before, immediately and 60 min after the exercise. Plasma concentrations of IL-12 were measured using enzyme-linked immunosorbent assay. Variance analysis revealed no significant effect of Ramadan on Ppeak and Pmean during the three testing periods. Considering the effect of Ramadan on plasma concentrations of IL-12, analysis of the variance revealed a significant Ramadan effect [F[2, 16]=66.27 ; P<0.001] as well as a significant time effect [F[2, 16]=120.66; P<0.001]. However, no significant [Ramadan time] of test interaction [F[4, 32]=2.40; P>0.05]. For all measures, IL-12 levels were lower during 1WR and 4WR in comparison with AR [P<0.05]. Considering the exercise effects, IL-12 levels measured immediately after the exercise were significantly higher than those measured before and at 60 minutes after the exercise [P<0.001]. These results suggest that an acute intense exercise-induced IL-12 response is modified by daytime fasting and modifications in sleep schedule during Ramadan