Caffeine's small edge holds up in female team-sport athletes

Most of what is known about caffeine and sport performance comes from studies of men, leaving female athletes to borrow conclusions from a population that may not represent them. Team sports add another layer of complexity, because performance there depends on repeated sprints, agility, jumping and skill execution rather than a single sustained effort. Whether caffeine's well-known ergogenic reputation holds up specifically in female team-sport athletes, and across which outcomes, has been an open question. This meta-analysis set out to quantify those effects domain by domain and to test whether factors like dose or timing change the answer.

The authors systematically searched PubMed and Web of Science for randomised, placebo-controlled crossover trials of acute, dose-defined caffeine in female team-sport athletes, a design in which each athlete completes testing under both caffeine and placebo. Twenty-six such trials were included. Effect sizes were expressed as Hedges' g and synthesised within each outcome domain using a three-level model with cluster-robust methods, alongside assessments of risk of bias, methodological quality and certainty of evidence. Physical, sport-specific, physiological, perceptual and cognitive outcomes were analysed separately, with exploratory checks for moderation by dose, timing, formulation, sport type, competitive level and habitual caffeine intake.

Physical performance showed a small favourable effect overall (g = 0.32), with statistical support for repeated sprint ability (g = 0.43), agility and change of direction (g = 0.42), sprint speed (g = 0.39), anaerobic power (g = 0.30) and jumping (g = 0.29). Perceptual responses improved modestly (g = 0.42), largely through a reduced rating of perceived exertion (g = 0.35). Sport-specific performance leaned favourable but did not reach conventional significance (g = 0.36), and cognitive findings, drawn from only four studies, were too uncertain to interpret. Caffeine raised heart rate, the expected response to a stimulant, while blood lactate and glucose showed no clear effects, and no moderator, including dose and timing, showed reliable influence.

This analysis extends the caffeine literature into a group it has historically neglected, and the direction of the findings matches what has long been reported elsewhere: small, real improvements in physical output and a lower sense of effort. What it does not support is the broader folklore, that caffeine sharpens skills, accuracy or cognition on the pitch, where evidence remains sparse. It also undercuts confident advice about optimal doses or timing, since no moderator analysis proved reliable. The authors call for future trials to report menstrual-cycle phase, hormonal-contraceptive use and habitual intake, gaps that still cloud interpretation.

For female athletes in team sports, this is a reason to think caffeine's performance edge applies to them too, not just to the men who dominated earlier studies. The honest size of that edge is small, concentrated in raw physical outputs like sprinting and jumping, and accompanied by exercise feeling somewhat easier. Claims that caffeine will improve shooting, passing or decision-making are not supported by current data. None of this constitutes advice on whether or how much caffeine to take; it simply maps where the evidence is solid and where it runs out.