Glucose kinetics during high-intensity exercise in endurance-trained and untrained humans

A. R. Coggan, C. A. Raguso, B. D. Williams, L. S. Sidossis, A. Gastaldelli

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Abstract

In humans, endurance training reduces the rates of glucose production and utilization during moderate-intensity exercise. It is uncertain, however, whether this is also true during high-intensity exercise. Accordingly, we studied eight endurance-trained cyclists and eight untrained subjects during 30 min of cycling at ~80% of maximal oxygen uptake (V̇O(2 max)). Rates of glucose appearance (Ra) and disappearance (Rd) were determined using a primed, continuous infusion of [6,6-2H]glucose. Average glucose Ra during exercise did not differ in the trained and untrained subjects (34.3 ± 3.6 vs. 36.0 ± 1.7 μmol · min-1 · kg-1; mean ± SE; P, not significant). Plasma insulin, glucagon, norepinephrine, and epinephrine concentrations were also similar in the two groups. In contrast, glucose Rd during exercise was 19% lower in the trained compared with the untrained subjects (27.0 ± 2.6 vs. 33.2 ± 1.5 μmol · min-1 · kg-1; P < 0.001). Consequently, during exercise, plasma glucose concentration rose significantly (P < 0.05) in the trained subjects but did not change in the untrained subjects. We conclude that utilization of plasma glucose is lower in trained subjects during high- intensity exercise, even when the exercise is performed at the same relative (and therefore a higher absolute) intensity as in the untrained state. Hyperglycemia in trained subjects during intense exercise appears to be due to this lower rate of glucose utilization rather than a higher rate of glucose production.

Original languageEnglish (US)
Pages (from-to)1203-1207
Number of pages5
JournalJournal of Applied Physiology
Volume78
Issue number3
DOIs
StatePublished - Jan 1 1995

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Keywords

  • catecholamines
  • glucoregulation
  • hepatic glucose production
  • hyperglycemia

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Coggan, A. R., Raguso, C. A., Williams, B. D., Sidossis, L. S., & Gastaldelli, A. (1995). Glucose kinetics during high-intensity exercise in endurance-trained and untrained humans. Journal of Applied Physiology, 78(3), 1203-1207. https://doi.org/10.1152/jappl.1995.78.3.1203