CAFFEINE DOES NOT ENHANCE INTERMITTENT, HIGH-INTENSITY EXERCISE
Herman, J. A., & Young, J. C. (1998). The effect of caffeine on high-intensity, intermittent exercise to exhaustion. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 1383.
Caffeine has been purported to increase endurance exercise time to exhaustion. The purpose of this study was to assess whether it affected intermittent high-intensity exercise in the same way. Males (N = 7) performed a high-intensity exercise under caffeine (6 mg/kg) and placebo condition. The workload was 120% of peak power output for 60 seconds followed by 120 seconds of recovery at 50 watts. This regimen was repeated until exhaustion.
Despite significant increases in blood caffeine (1.7 to 4.5 ug/ml) there was no performance difference between the conditions. Peak blood lactate was also similar between conditions.
Implication. Caffeine does not enhance intermittent high-intensity exercise performance.