Study note • PMID 25970669
[Performance enhancement by carbohydrate intake during sport: effects of carbohydrates during and after high-intensity exercise].
Worth trying if it fits your goal and context.
ELI5
In plain language
Endogenous carbohydrate availability does not provide sufficient energy for prolonged moderate to high-intensity exercise. (review; well-trained athletes).
In this review, the abstract is mixed or unclear for Time-trial performance. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.
Takeaways
What the abstract suggests
- • Study question: Endogenous carbohydrate availability does not provide sufficient energy for prolonged moderate to high-intensity exercise.
- • In this review, the abstract is mixed or unclear for Time-trial performance.
- • Population: well-trained athletes.
- • Protocol cues (title/abstract): 1.2 g/kg • 0.8 g/kg • 0.4 g/kg • 2.5 hours • 24 hours.
Protocol
Protocol (as reported)
- • Intervention/exposure: carbohydrate, carb.
- • Dose/time/duration cues in abstract/title: 1.2 g/kg • 0.8 g/kg • 0.4 g/kg • 2.5 hours • 24 hours.
- • Outcomes: Time to exhaustion, Time-trial performance, Fat oxidation.
- • 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 athletes) working on fueling.
- • Athletes who can measure Time to exhaustion, Time-trial performance, Fat oxidation 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: review.
- • Population: well-trained athletes.
- • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
- • Protocol cues mentioned: 1.2 g/kg • 0.8 g/kg • 0.4 g/kg • 2.5 hours • 24 hours.
- • Source: PubMed PMID 25970669 (2015) — Nederlands tijdschrift voor geneeskunde.
Results excerpt
What the abstract reports
“Carbohydrate ingestion during high-intensity exercise can therefore enhance performance.- For exercise lasting 1 to 2.5 hours, athletes are advised to ingest 30-60 g of carbohydrates per hour.- Well-trained endurance athletes competing for longer than 2.5 hours at high intensity can metabolise up to…”
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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Practical performance outcome used in many studies: closer to racing than lab-only metrics.