Taken from tritalk.co.uk
“Caffeine is one of the few proven ergogenic aids- the current optimum dosage that is needed is 5-mg/kg in the 60-90 minutes pre race or heavy session- the dose response curve flattens out after this. Caffeine is rapidly absorbed from the gut and reaches peak plasma concentrations within 1 hour- the blood half life is 3-6 hours, so shorter races do not need “maintenance doses”
Dose response was done with cyclists given 5,9 and 13mg/kg caffeine and this was the trial that showed no improvement gains above 5mg/kg.
Caffeine has been shown to extend endurance in strenuous aerobic exercise and also improves muscular strength and endurance in prolonged exercise. This has been placebo control trialled. The benefits have been shown to persist up to 5 hours after the initial dose.
Caffeine also theoretically mobilises free fatty acids and increases fat catabolism and reduces carb oxidation, but one study did not demonstrate any increase in plasma FFAs
Studies also done on swimmers doing 1500m trials and showed that each 500m split improved with caffeine and total swim time improved on average by 1.9%, though I am not sure how statistically valid this is.
Running studies have taken ” time to fatigue” and caffeine gave significant duration increases.
Interestingly, one study subjectively demonstrated a reduction in perceived exertion for the same exercise.
Second surge energy gel has 100mg caffeine in it
High 5 Energy Source extreme has 180mg/ sachet
SIS gels have 50mg
High 5 gels have 30mg