Cognitive effects of guarana supplementation with maximal intensity cycling
Gurney T, et al.
Published in British Journal of Nutrition
Methodology
Randomised, double-blind crossover trial in 25 participants receiving guarana 125 mg/kg, caffeine 5 mg/kg or placebo (65 mg/kg protein powder) on three separate days; after 30 minutes rest they completed simple and choice reaction time tests, immediate word recall and the Bond-Lader mood scale, then a cycling VO2max test followed by immediate repeat testing.
Key Findings
25 participants completed a randomised double-blind crossover comparing guarana (125 mg/kg), caffeine (5 mg/kg) and placebo, with cognitive tests before and immediately after a maximal cycling VO2max test. Before exercise, guarana improved choice reaction time (407 ms vs 421 ms for placebo, p = 0.030) but not significantly versus caffeine (417 ms). After exercise, simple reaction time was faster with guarana (306 ms) than placebo (323 ms, p = 0.003) but not caffeine (315 ms), and alertness scores were higher with guarana (63.3) than placebo (57.4, p = 0.014). There were no changes in VO2max, immediate word recall or any other Bond-Lader mood measure.
Conclusions
Guarana supplementation appears to impact several parameters of cognition, possibly maintaining speed of attention immediately following maximal intensity exercise.
Limitations
Only 25 participants tested on single days, with guarana never significantly outperforming an equivalent caffeine dose, so the effects may simply reflect caffeine content; memory and physical performance were unchanged.
Related Health Concerns
Study Details
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