Mixed
Ingesting 100 mg of slow-release caffeine in a carbohydrate performance bar significantly improves complex cognitive processing speed and endurance time-to-exhaustion during prolonged moderate-intensity cycling.
For endurance athletes, consuming a bar with 100mg of slow-release caffeine along with carbohydrates before and during exercise (e.g., at 55 and 115 minutes) can improve both your mental focus on complex tasks and your physical ability to sustain effort. This approach does not increase perceived fatigue or side effects compared to just eating carbs or doing nothing, making it a viable strategy for events requiring sustained concentration.
Caffeine in a performance bar can significantly improve endurance performance and complex cognitive ability during and after exercise.
Why this rating
Randomized, double-blind, placebo-controlled crossover design with well-trained subjects, though sample size is modest (n=24).
Source
Caffeine Improves Physical and Cognitive Performance during Exhaustive Exercise
Eef Hogervorst et al. · Medicine & Science in Sports & Exercise · 2008
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