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Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids
- Source :
- Scopus-Elsevier
- Publication Year :
- 2002
- Publisher :
- American Physiological Society, 2002.
-
Abstract
- The relative roles of circulatory glucose, muscle glycogen, and lipids in shivering thermogenesis are unclear. Using a combination of indirect calorimetry and stable isotope methodology ([U-13C]glucose ingestion), we have quantified the oxidation rates of these substrates in men acutely exposed to cold for 2 h (liquid conditioned suit perfused with 10°C water). Cold exposure stimulated heat production by 2.6-fold and increased the oxidation of plasma glucose from 39.4 ± 2.4 to 93.9 ± 5.5 mg/min (+138%), of muscle glycogen from 126.6 ± 7.8 to 264.2 ± 36.9 mg glucosyl units/min (+109%), and of lipids from 46.9 ± 3.2 to 176.5 ± 17.3 mg/min (+376%). Despite the observed increase in plasma glucose oxidation, this fuel only supplied 10% of the energy for heat generation. The major source of carbohydrate was muscle glycogen (75% of all glucose oxidized), and lipids produced as much heat as all other fuels combined. During prolonged, low-intensity shivering, we conclude that total heat production is unequally shared among lipids (50%), muscle glycogen (30%), plasma glucose (10%), and proteins (10%). Therefore, future research should focus on lipids and muscle glycogen that provide most of the energy for heat production.
- Subjects :
- Adult
Blood Glucose
Male
medicine.medical_specialty
Physiology
Fatty Acids, Nonesterified
Body Temperature
Lipid peroxidation
chemistry.chemical_compound
Oxygen Consumption
Physiology (medical)
Internal medicine
medicine
Humans
Insulin
Lactic Acid
Muscle, Skeletal
Glycogen
Chemistry
Calorimetry, Indirect
Lipid metabolism
Metabolism
Carbohydrate
Lipid Metabolism
Cold Temperature
Endocrinology
Area Under Curve
Heat generation
Shivering
Lipid Peroxidation
medicine.symptom
Oxidation-Reduction
Thermogenesis
Algorithms
Body Temperature Regulation
Subjects
Details
- ISSN :
- 15221601 and 87507587
- Volume :
- 93
- Database :
- OpenAIRE
- Journal :
- Journal of Applied Physiology
- Accession number :
- edsair.doi.dedup.....1e95cd741b2698e8ebb649244f41b0c3