The purpose of this study was to examine the effect of caffeine supplementation on glucose and blood lactate levels after 1 and 20-km cycling. 15 time trial cyclist from Shiraz province participated in this research. In the first stage, subjects received placeboes at three intervals (30 minutes before, 5 minutes before, and immediately after the 1 and 20-km cycling). In the second and third stages (with a 5-day interval between each two stages), all the subjects received caffeine gum with two different doses (180 and 300 mg) at three intervals, likes the first stage. The participants were instructed to chew the gum for 5 minutes. Blood glucose and lactate of the subjects were measured in all three stages, 5 minutes before and immediately after performing the tests. The results of repeated measure ANOVA and Tukey’s post hoc test indicated that both doses of caffeine have a significant effect on blood lactate and glucose levels after 20-km cycling, but in 1-km cycling group glucose levels did not have significant differences between pre and posttest.In conclusion, based on the results of the research, caffeine can affects on glucose and lactate level after endurance cycling, but not after semi endurance cycling. It is possible thatthe nature of endurance exercise besides caffeine supplementation can affect on glucose and blood lactate levels after exercise.
