Trial reportJournal of sport and health science2024
Dose-response effect of pre-exercise carbohydrates under muscle glycogen unavailability: Insights from McArdle disease.
Trial report in Journal of sport and health science, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
4 citing papers in PubMed, 8 citations in OpenAlex.
- Cardiovascular involvement in glycogen storage diseases.Nature reviews. Cardiology · 2026Review
- Physical exercise intervention in glycogen storage disease IIIa: Feasibility and multisystem benefits.Experimental physiology · 2026Article
- Factors Influencing Blood Lactate Concentration During Exercise: A Narrative Review With a Lactate Shuttle Perspective.Acta physiologica (Oxford, England) · 2025Review
- Article
Corrections and comments
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Authors and funding
11 authors at 6 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThis study aimed to determine the effect of different carbohydrate (CHO) doses on exercise capacity in patients with McArdle disease-the paradigm of "exercise intolerance", characterized by complete muscle glycogen unavailability-and to determine whether higher exogenous glucose levels affect metabolic responses at the McArdle muscle cell (in vitro) level.
methodsPatients with McArdle disease (n = 8) and healthy controls (n = 9) underwent a 12-min submaximal cycling constant-load bout followed by a maximal ramp test 15 min after ingesting a non-caloric placebo. In a randomized, double-blinded, cross-over design, patients repeated the tests after consuming either 75 g or 150 g of CHO (glucose:fructose = 2:1). Cardiorespiratory, biochemical, perceptual, and electromyographic (EMG) variables were assessed. Additionally, glucose uptake and lactate appearance were studied in vitro in wild-type and McArdle mouse myotubes cultured with increasing glucose concentrations (0.35, 1.00, 4.50, and 10.00 g/L).
resultsCompared with controls, patients showed the "classical" second-wind phenomenon (after prior disproportionate tachycardia, myalgia, and excess electromyographic activity during submaximal exercise, all p < 0.05) and an impaired endurance exercise capacity (-51% ventilatory threshold and -55% peak power output, both p < 0.001). Regardless of the CHO dose (p < 0.05 for both doses compared with the placebo), CHO intake increased blood glucose and lactate levels, decreased fat oxidation rates, and attenuated the second wind in the patients. However, only the higher dose increased ventilatory threshold (+27%, p = 0.010) and peak power output (+18%, p = 0.007). In vitro analyses revealed no differences in lactate levels across glucose concentrations in wild-type myotubes, whereas a dose-response effect was observed in McArdle myotubes.
conclusionCHO intake exerts beneficial effects on exercise capacity in McArdle disease, a condition associated with total muscle glycogen unavailability. Some of these benefits are dose dependent.
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