Research

Hormonal

Maintaining high plasma glucose concentrations during exercise improves performance through mechanisms other than substrate (glycogen/fat) oxidation rates.

Don't worry about 'saving' your muscle glycogen by eating carbs during exercise. The benefit comes from keeping your blood sugar stable, which likely helps your central nervous system manage fatigue, allowing you to perform better in the final stages of a long workout.

GoodQualifiesHIGH confidence
Hence, it appears that the maintenance of high (i.e., 6 mM) plasma glucose concentrations typically associated with the ingestion of CHO throughout exercise may improve exercise performance by mechanisms other than alterations in substrate utilization, such as negative central nervous system changes, as previously suggested
Mark A. Febbraio et al. · Journal of Applied Physiology · 2000

Why this rating

Strong metabolic data (glucose kinetics, oxidation rates) supports the exclusion of substrate metabolism as the cause.

Source

Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance

Mark A. Febbraio et al. · Journal of Applied Physiology · 2000

DOI 10.1152/jappl.2000.89.6.2220

crossover · n=7Cited 189×
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DOI resolved against Crossref · corpus check 2026-06-10

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