Study note • PMID 36615805
Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis.
Worth trying if it fits your goal and context.
ELI5
In plain language
Caffeine (1,3,7-trimethylxanthine) is one of the most widely consumed performance-enhancing substances in sport due to its well-established ergogenic effects. (systematic review / meta-analysis; well-trained runners).
Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.
Takeaways
What the abstract suggests
- • Study question: Caffeine (1,3,7-trimethylxanthine) is one of the most widely consumed performance-enhancing substances in sport due to its well-established ergogenic effects.
- • Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions.
- • Population: well-trained runners.
- • Protocol cues (title/abstract): 9 mg/kg.
Protocol
Protocol (as reported)
- • Intervention/exposure: caffeine.
- • Dose/time/duration cues in abstract/title: 9 mg/kg.
- • Outcomes: Time-trial performance, Time to exhaustion.
- • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.
Fit
Who it helps, and who should skip it
Who it helps
- • Athletes similar to the study population (well-trained runners) working on supplements.
- • Athletes who can measure Time-trial performance, Time to exhaustion with a repeatable workout or time-trial effort.
Who should skip
- • If you have symptoms or conditions that make the intervention risky, get professional guidance.
- • If you’re near race day and can’t safely test, defer the experiment.
Methods
What the study actually did
- • Design: systematic review / meta-analysis (randomized, double-blind, placebo-controlled, crossover).
- • Population: well-trained runners.
- • Outcomes measured: Time-trial performance, Time to exhaustion.
- • Protocol cues mentioned: 9 mg/kg.
- • Source: PubMed PMID 36615805 (2022) — Nutrients.
Full paper
What the full paper adds
- • Design features (paper): randomized, double-blind, placebo-controlled, crossover.
- • Participants (paper): well-trained runners.
- • Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions.
Results excerpt
What the abstract reports
“A total of 21 randomized controlled trials were included in the analysis, with caffeine doses ranging between 3 and 9 mg/kg.”
Note: excerpts are short; for full context, read the paper.
Limits
Limitations & bias
- • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
- • Reviews and consensus statements mix protocols and populations; recommendations may not match your exact constraints.
- • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
- • This is performance information, not medical advice.
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Performance Science Lab
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Supplements performance research
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Caffeine for endurance performance: a practical protocol
Evidence-informed protocol: Caffeine for endurance performance: a practical protocol. Practical steps, who it helps, and what to watch out for.
Time-trial performance research for endurance athletes
Practical performance outcome used in many studies: closer to racing than lab-only metrics.
Time to exhaustion research for endurance athletes
A lab outcome that can still guide training: it often tracks fatigue resistance.