The Claim
Caffeine administration via capsules and mouth rinses at 3 mg/kg does not produce consistent cognitive benefits in adolescent male volleyball players during evening sessions, despite elevated baseline performance, indicating that the ergogenic effects of caffeine are reduced under conditions of naturally high circadian alertness.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Caffeine given as capsules or mouth rinses at 3 mg/kg does not consistently improve thinking performance in adolescent male volleyball players during evening training, even though their baseline performance is already high due to natural daily rhythms in alertness.
See the scientific wording
Caffeine capsules and mouth rinses at 3 mg/kg show no consistent cognitive benefits in adolescent male volleyball players during evening sessions, despite improved baseline performance, indicating that caffeine’s ergogenic effects are attenuated when circadian alertness is naturally high.
When caffeine enters the body, it blocks a chemical in the brain that makes you feel tired. This allows other chemicals that keep you alert to become more active, which improves focus and reaction speed. But if you're already fully awake because of your body's natural rhythm, blocking that tiredness chemical doesn't make you any more alert or faster at thinking.
What the research says
1 studyWhen teen volleyball players took caffeine in the evening, their brains were already super alert naturally, so the caffeine didn’t help them think any better. The study shows caffeine only helps when you’re not already wide awake.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.