Research

Hormonal

Caffeine ingestion (6 mg/kg) does not enhance power output during repeated short-term high-intensity exercise and may negatively affect performance in later bouts.

If you rely on caffeine for short, maximal sprints (like Wingate tests or repeated HIIT intervals), it likely won't help and might actually reduce your peak power in later sets. The traditional belief that caffeine boosts all high-intensity performance is not supported by this data. Save the caffeine for endurance activities where its benefits are clearer.

GoodRefutesHIGH confidence
Caf ingestion did not have any effect on power output (peak or average) in the first two WG tests and had a negative effect in the latter two exercise bouts.
Felicia Greer et al. · Journal of Applied Physiology · 1998

Why this rating

Randomized, double-blind, placebo-controlled trial with healthy, active subjects, though small sample size (n=9).

Source

Caffeine, performance, and metabolism during repeated Wingate exercise tests

Felicia Greer et al. · Journal of Applied Physiology · 1998

DOI 10.1152/jappl.1998.85.4.1502

crossover · n=9Cited 241×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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