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Cited by 598Cardiovascular and exercise physiologyMuscle metabolism and nutritionMetabolism, Diabetes, and Cancer

Glucose metabolism during leg exercise in man

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Wahren, John, Felig, Philip, Ahlborg, Gunvor, Jorfeldt, Lennart·1971·Journal of Clinical Investigation
DOI 10.1172/jci106772PMC PMC292221
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Abstract

Arterial concentrations and net substrate exchange across the leg and splanchnic vascular bed were determined for glucose, lactate, pyruvate, and glycerol in healthy postabsorptive subjects at rest and during 40 min of exercise on a bicycle ergometer at work intensities of 400, 800, and 1200 kg-m/min. Rising arterial glucose levels and small decreases in plasma insulin concentrations were found during heavy exercise. Significant arterial-femoral venous differences for glucose were demonstrated both at rest and during exercise, their magnitude increasing with work intensity as well as duration of the exercise performed. Estimated glucose uptake by the leg increased 7-fold after 40 min of light exercise and 10- to 20-fold at moderate to heavy exercise. Blood glucose uptake could at this time account for 28-37% of total substrate oxidation by leg muscle and 75-89% of the estimated carbohydrate oxidation. Splanchnic glucose production increased progressively during exercise reaching levels 3 to 5-fold above resting values at the heavy work loads. Close agreement was observed between estimates of total glucose turnover during exercise based on leg glucose uptake and splanchnic glucose production. Hepatic gluconeogenesis-estimated from splanchnic removal of lactate, pyruvate, glycerol, and glycogenic amino acids-could supply a maximum of 25% of the resting hepatic glucose production but could account for only 6-11% of splanchnic glucose production after 40 min of moderate to heavy exercise. IT IS CONCLUDED THAT: (a) blood glucose becomes an increasingly important substrate for muscle oxidation during prolonged exercise of this type: (b) peripheral glucose utilization increases in exercise despite a reduction in circulating insulin levels: (c) increased hepatic output of glucose, primarily by means of augmented glycogenolysis, contributes to blood glucose homeostasis in exercise and provides an important source of substrate for exercising muscle.

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Crossref · 10.1172/jci106772

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63 of 63 references verified0 citation errors · 0 not checkable

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  • During exercise, an appreciable amount (15-30%) of the energy required for moderate exercise is obtained from blood glucose.

    “In fact, an appreciable amount (15–30%) of the energy required for moderate exercise is obtained from blood glucose [101]”

    From Regulation of Energy Substrate Metabolism in Endurance Exercise (2021) · cites this paper as [101]

    Table VII (Discussion; page unavailable) estimates that blood glucose supplied 29% of leg-muscle oxygen uptake after 40 minutes at the moderate workload, supporting the claim’s general point. It does not establish 15–30% throughout moderate exercise: the estimate was 8% after 10 minutes, and the figures concern leg-muscle oxidation rather than all energy required for exercise. (LLM, conf=0.85)

    Experimental — accuracy not yet measured

  • Glucose output is almost entirely derived from liver glycogenolysis at the initial stages of prolonged moderate to high-intensity exercise secondary to glucagon and noradrenaline-mediated activation of hepatic glycogen phosphorylase.

    “Glucose output is almost entirely derived from liver glycogenolysis at the initial stages of prolonged moderate to high-intensity exercise secondary to glucagon and noradrenaline-mediated activation of hepatic glycogen phosphorylase [101,102].”

    From Regulation of Energy Substrate Metabolism in Endurance Exercise (2021) · cites this paper as [101]

    The Discussion (page not available) says hepatic glycogenolysis supplies the major part of splanchnic glucose during exercise, particularly at heavy workloads. But Table VIII estimates that gluconeogenic precursors could supply 19.6–29.2% at 10 minutes; the 6–11% estimate applies after 40 minutes, not the initial stage. The Discussion treats adrenergic activity and glucagon secretion as possibilities, not established causes, and does not establish activation of hepatic glycogen phosphorylase. (LLM, conf=0.90)

    Experimental — accuracy not yet measured

  • Although the kidney is capable of producing glucose, its contribution to glucose output during exercise is negligible.

    “It should be noted that although the kidney is capable of producing glucose, its contribution to glucose output during exercise is negligible [101].”

    From Regulation of Energy Substrate Metabolism in Endurance Exercise (2021) · cites this paper as [101]

  • During acute exercise in humans, blood glucose typically remains stable, with the liver releasing glucose for brain and skeletal muscle use.

    “In a human model, the blood concentration of glucose typically remains stable during acute exercise, with the liver releasing glucose for brain and skeletal muscle usage28.”

    From Exerkines in health, resilience and disease (2022) · cites this paper as [28]

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Cites

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Research works printed but not linked: 3

  1. Cahill, G. F., Jr., and 0. E. Owen. 1968. Some ob- servations on carbohydrate metabolism in man. In Car- bohydrate Metabolism and its Disorders. F. Dickens, P. J. Randle, and W. J. Whelan, editors. Academic Press, Inc., New York. 1: 497.
  2. Bradley, S. E. 1946. Liver function as studied by hepatic vein catheterization. In Transactions of the Fifth Con- ference on Liver Injury. Josiah Macy, Jr. Foundation, New York. 38.
  3. Jorfeldt, L., and J. Wahren. 1971. Leg blood flow dur- ing exercise. Clin. Sci. (London). In press.

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Related

Authors
Wahren, J., Felig, P., Ahlborg, G., & Jorfeldt, L.
Affiliations
Karolinska Institutet (SE)
Venue
Journal of Clinical Investigation
Publisher
American Society for Clinical Investigation
Published
1971-12-01
Volume
50
Issue
12
Pages
2715-2725
ISSN
0021-9738 (ISSN-L)
DOI
10.1172/jci106772
PMC
PMC292221
OpenAlex
W2011985622
Cited by
598
References
63
Citations by year
2026: 5 · 2025: 4 · 2024: 10 · 2023: 9 · 2022: 16 · 2021: 19 · 2020: 14 · 2019: 6 · 2018: 10 · 2017: 7 · 2016: 11 · 2015: 10 · 2014: 10 · 2013: 11 · 2012: 5
FWCI
21.19
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
Medical Research Council
Topics
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
Keywords
glucose metabolism, leg exercise, glucose uptake, hepatic gluconeogenesis, glycogenolysis, insulin, blood glucose, carbohydrate oxidation, lactate, pyruvate, glycerol, blood flow, exercise intensity, blood glucose homeostasis
MeSH terms
Abdomen, Adult, Blood Glucose, Physical Exertion, Fatty Acids, Nonesterified, Glucose, Glycerol, Heart Rate, Humans, Insulin, Lactates, Leg, Liver, Male, Methods, Muscles, Oxygen, Oxygen Consumption, Pyruvates, Regional Blood Flow, Rest, Time Factors

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