Oral [13C]glucose oxidation during prolonged exercise after high- and low-carbohydrate diets

• Published in: Journal of applied physiology (1985) Vol. 85; no. 2; pp. 723 - 730
• Main Authors: Peronnet, F, Rheaume, N, Lavoie, C, Hillaire-Marcel, C, Massicotte, D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01-08-1998; American Physiological Society
• Subjects: Adult; Anatomy & physiology; Biological and medical sciences; Blood Glucose - metabolism; Carbohydrates; Carbon Dioxide - metabolism; Diet; Dietary Carbohydrates - pharmacology; Dietary Proteins - metabolism; Exercise; Exercise - physiology; Exercise Test; Fundamental and applied biological sciences. Psychology; Glucose; Glucose - metabolism; Humans; Liver - metabolism; Male; Metabolisms and neurohumoral controls; Oxidation; Oxidation-Reduction; Oxygen Consumption - drug effects; Oxygen Consumption - physiology; Urea - urine; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Physical exercise; Human; Radiolabelling; Bicycle ergometer; Carbohydrate; Oxidation; Supplemented diet; Glucose; Feeding; Prolonged
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1998.85.2.723

1  Université de
Montréal, Montreal, Quebec H3C 3J7;
2  Université du
Québec à Trois Rivières, Trois Rivières,
Quebec G9A 5H7; and
3  Université du
Québec à Montréal, Montreal, Quebec, Canada H3C
3P8
The effect of a diet either high or low in carbohydrates (CHO)
on exogenous 13 C-labeled glucose
oxidation (200 g) during exercise (ergocycle: 120 min at 64.0 ± 0.5% maximal oxygen uptake) was studied in six subjects. Between 40 and 80 min, exogenous glucose oxidation was significantly higher after
the diet low in CHO (0.63 ± 0.05 vs. 0.52 ± 0.04 g/min), but
this difference disappeared between 80 and 120 min (0.71 ± 0.03 vs.
0.69 ± 0.04 g/min). The oxidation rate of plasma glucose, computed
from the volume of
13 CO 2
produced the
13 C-to- 12 C
ratio in plasma glucose at 80 min, and of glucose released from the
liver, computed from the difference between plasma glucose and
exogenous glucose oxidation, was higher after the diet low in CHO (1.68 ± 0.26 vs. 1.41 ± 0.17 and 1.02 ± 0.20 vs. 0.81 ± 0.14 g/min, respectively). In contrast the oxidation rate of
glucose plus lactate from muscle glycogen (computed from the difference between total CHO oxidation and plasma glucose oxidation) was lower
(0.31 ± 0.35 vs. 1.59 ± 0.20 g/min). After a diet low in CHO,
the oxidation of exogenous glucose and of glucose released from the
liver is increased and partly compensates for the reduction in muscle
glycogen availability and oxidation.
diet; carbohydrate stores; metabolic response; insulin