Document Detail


Effects of endurance training on lactate removal by oxidation and gluconeogenesis during exercise.
MedLine Citation:
PMID:  8594549     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This report describes the effects of 9 weeks of endurance-training on the relative rates of lactate removal via oxidation and gluconeogenesis in humans. Before and after training, eight subjects performed incremental (60 W plus 40 W every 6 min) exercise tests, while 14C-lactate was infused into one forearm vein and arterialized venous blood was sampled from the other forearm. During the trial, the volume of expired 14CO2 and circulating 14C-lactate and 14C-glucose specific radioactivities were measured. Such measurements revealed that training increased the estimated oxidation of equivalent venous blood lactate concentrations [VLa] of greater than 1.6 mmol/l. These increases in lactate oxidation were more than would be predicted from the approximately 40% higher O2 uptake values at any [VLa] after training. At a [VLa] of 6 mmol/l, rates of lactate oxidation were increased by some 100% following training, from 105 +/- 12 to 208 +/- 33 micromol/min/kg (P < 0.01). Improvements in lactate oxidation after training reduced the estimated rates of lactate-to-glucose conversion from 40 +/- 3 to 9 +/- 2 micromol/min/kg at a [VLa] of 2.5 mmol/l (P < 0.01). Thus, unlike in rats, human endurance-training does not increase gluconeogenesis. In the final stages of progressive exercise after training, more than 80% of lactate was oxidised and accounted for approximately 45% of overall carbohydrate oxidation.
Authors:
H H MacRae; T D Noakes; S C Dennis
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  430     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  1995 Oct 
Date Detail:
Created Date:  1996-04-09     Completed Date:  1996-04-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  964-70     Citation Subset:  IM    
Affiliation:
Medical Research Council Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory 7925, South Africa.
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MeSH Terms
Descriptor/Qualifier:
Adult
Carbohydrate Metabolism
Gluconeogenesis*
Humans
Lactates / blood*
Lactic Acid
Male
Oxidation-Reduction
Physical Endurance / physiology
Physical Exertion / physiology*
Chemical
Reg. No./Substance:
0/Lactates; 50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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