Document Detail

Leg and arm lactate and substrate kinetics during exercise.
MedLine Citation:
PMID:  12388120     Owner:  NLM     Status:  MEDLINE    
To study the role of muscle mass and muscle activity on lactate and energy kinetics during exercise, whole body and limb lactate, glucose, and fatty acid fluxes were determined in six elite cross-country skiers during roller-skiing for 40 min with the diagonal stride (Continuous Arm + Leg) followed by 10 min of double poling and diagonal stride at 72-76% maximal O(2) uptake. A high lactate appearance rate (R(a), 184 +/- 17 micromol x kg(-1) x min(-1)) but a low arterial lactate concentration ( approximately 2.5 mmol/l) were observed during Continuous Arm + Leg despite a substantial net lactate release by the arm of approximately 2.1 mmol/min, which was balanced by a similar net lactate uptake by the leg. Whole body and limb lactate oxidation during Continuous Arm + Leg was approximately 45% at rest and approximately 95% of disappearance rate and limb lactate uptake, respectively. Limb lactate kinetics changed multiple times when exercise mode was changed. Whole body glucose and glycerol turnover was unchanged during the different skiing modes; however, limb net glucose uptake changed severalfold. In conclusion, the arterial lactate concentration can be maintained at a relatively low level despite high lactate R(a) during exercise with a large muscle mass because of the large capacity of active skeletal muscle to take up lactate, which is tightly correlated with lactate delivery. The limb lactate uptake during exercise is oxidized at rates far above resting oxygen consumption, implying that lactate uptake and subsequent oxidation are also dependent on an elevated metabolic rate. The relative contribution of whole body and limb lactate oxidation is between 20 and 30% of total carbohydrate oxidation at rest and during exercise under the various conditions. Skeletal muscle can change its limb net glucose uptake severalfold within minutes, causing a redistribution of the available glucose because whole body glucose turnover was unchanged.
G Van Hall; M Jensen-Urstad; H Rosdahl; H-C Holmberg; B Saltin; J A L Calbet
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2002-09-11
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  284     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2003 Jan 
Date Detail:
Created Date:  2002-12-17     Completed Date:  2003-01-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E193-205     Citation Subset:  IM    
The Copenhagen Muscle Research Centre, University Hospital, Denmark.
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MeSH Terms
3-Hydroxyacyl CoA Dehydrogenases / analysis
Arm / blood supply*
Blood Glucose / analysis
Citrate (si)-Synthase / analysis
Energy Metabolism*
Exercise / physiology*
Fatty Acids, Nonesterified / blood
Femoral Artery
Femoral Vein
Heart Atria
L-Lactate Dehydrogenase / analysis
Lactic Acid / blood*
Leg / blood supply*
Muscle, Skeletal / blood supply,  enzymology,  physiology*
Oxygen Consumption
Subclavian Vein
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 50-21-5/Lactic Acid; EC Dehydrogenase; EC CoA Dehydrogenases; EC (si)-Synthase

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