Study note • PMID 3525502
Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate.
How to use this page
This note summarizes one study record. Check the participants, methods, results, and limitations before applying it to training.
- • Design signal: controlled study.
- • Population relevance: athlete/trained context.
- • Consistency: single-study evidence.
- • Practical recommendation depends on tolerance, context, and whether it protects training consistency.
ELI5
In plain language
The purpose of this study was to determine whether the postponement of fatigue in subjects fed carbohydrate during prolonged strenuous exercise is associated with a slowing of muscle glycogen depletion. (controlled study; trained cyclists).
The abstract suggests a trade-off or negative effect affecting Time to exhaustion, Time-trial performance, Fat oxidation. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.
Takeaways
What the abstract suggests
- • Study question: The purpose of this study was to determine whether the postponement of fatigue in subjects fed carbohydrate during prolonged strenuous exercise is associated with a slowing of muscle glycogen depletion.
- • The abstract suggests a trade-off or negative effect affecting Time to exhaustion, Time-trial performance, Fat oxidation.
- • Population: trained cyclists.
- • Protocol cues (title/abstract): 2.0 g/kg • 0.4 g/kg • 20 min • 0.19 h • 2 h • 0.33 h.
Protocol
Protocol (as reported)
- • Intervention/exposure: carbohydrate, carb (vs placebo).
- • Dose/time/duration cues in abstract/title: 2.0 g/kg • 0.4 g/kg • 20 min • 0.19 h • 2 h • 0.33 h • 3 h.
- • 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 may help, and who should be cautious
Who it helps
- • Athletes similar to the study population (trained cyclists) 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 be cautious
- • 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: controlled study (placebo-controlled).
- • Population: trained cyclists.
- • Comparator: placebo.
- • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
- • Protocol cues mentioned: 2.0 g/kg • 0.4 g/kg • 20 min • 0.19 h • 2 h • 0.33 h • 3 h.
- • Source: PubMed PMID 3525502 (1986) — Journal of applied physiology (Bethesda, Md. : 1985).
Results excerpt
What the abstract reports
“The pattern of muscle glycogen utilization, however, was not different during the first 3 h of exercise with the placebo or the carbohydrate feedings.”
Note: excerpts are short; for full context, read the paper.
Limits
Limitations and 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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