Carbohydrate Ingestion Can Completely Suppress Endogenous Glucose Production during Exercise

suppress endogenous glucose production during exercise. Am. J. Physiol. 276 (Endocrinol. Metab. 39): E672–E683, 1999.— The purposes of this study were 1) to investigate the effect of carbohydrate (CHO) ingestion on endogenous glucose produc-tion (EGP) during prolonged exercise, 2) to study whether glucose appearance in the circulation could be a limiting factor for exogenous CHO oxidation, and 3) to investigate whether large CHO feedings can reduce muscle glycogen oxidation during exercise. Six well-trained subjects exercised three times for 120 min at 50 % maximum workload while ingesting water (FAST), a 4 % glucose solution (LO-Glc), or a 22 % glucose solution (HI-Glc). A primed continuous intrave-nous [6,6-2H2]glucose infusion was given, and the ingested glucose was enriched with [U-13C]glucose. Glucose ingestion significantly elevated CHO oxidation as well as the rates o