Study note • PMID 18799996
Caffeine improves physical and cognitive performance during exhaustive exercise.
Worth trying if it fits your goal and context.
ELI5
In plain language
To examine the effects of ingesting a performance bar, containing caffeine, before and during cycling exercise on physical and cognitive performance. (randomized trial; well-trained cyclists).
The abstract doesn’t indicate a 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: To examine the effects of ingesting a performance bar, containing caffeine, before and during cycling exercise on physical and cognitive performance.
- • The abstract doesn’t indicate a clear change in Time-trial performance, Time to exhaustion under the tested conditions.
- • Population: well-trained cyclists.
- • Protocol cues (title/abstract): 100 mg • 115 min • 140 min • 5 min • 60% VO2max • 75% VO2max.
Protocol
Protocol (as reported)
- • Intervention/exposure: caffeine (vs placebo).
- • Dose/time/duration cues in abstract/title: 100 mg • 115 min • 140 min • 5 min • 60% VO2max • 75% VO2max.
- • 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 cyclists) 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: randomized trial (placebo-controlled).
- • Population: well-trained cyclists.
- • Comparator: placebo.
- • Outcomes measured: Time-trial performance, Time to exhaustion.
- • Protocol cues mentioned: 100 mg • 115 min • 140 min • 5 min • 60% VO2max • 75% VO2max.
- • Source: PubMed PMID 18799996 (2008) — Medicine and science in sports and exercise.
Results excerpt
What the abstract reports
“Participants were significantly faster after CAF when compared with CHO on both the computerized complex information processing tests, particularly after 140 min and after the T2EX ride (P < 0.001).”
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).
- • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
- • 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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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.