Document Detail

Carnitine and physical exercise.
MedLine Citation:
PMID:  8857706     Owner:  NLM     Status:  MEDLINE    
Carnitine plays a central role in fatty acid (FA) metabolism. It transports long-chain fatty acids into mitochondria for beta-oxidation. Carnitine also modulates the metabolism of coenzyme-A (CoA). It is not surprising that the use of supplementary carnitine to improve physical performance has become widespread in recent years, although there is no unequivocal support to this practice. However, critical reflections and current scientific-based knowledge are important because the implications of reduced or increased carnitine concentrations in vivo are not thoroughly understood. Several rationales have been forwarded in support of the potential ergogenic effects of oral carnitine supplementation. However, the following arguments derived from established scientific observations may be forwarded: (i) carnitine supplementation neither enhances FA oxidation in vivo or spares glycogen or postpones fatigue during exercise. Carnitine supplementation does not unequivocally improve performance of athletes; (ii) carnitine supplementation does not reduce body fat or help to lose weight; (iii) in vivo pyruvate dehydrogenase complex (PDC) is fully active already after a few seconds of intense exercise. Carnitine supplementation induces no further activation of PDC in vivo; (iv) despite an increased acetyl-CoA/free CoA ratio, PDC is not depressed during exercise in vivo and therefore supplementary carnitine has no effect on lactate accumulation; (v) carnitine supplementation per se does not affect the maximal oxygen uptake (VO2max); (vi) during exercise there is a redistribution of free carnitine and acylcarnitines in the muscle but there is no loss of total carnitine. Athletes are not at risk for carnitine deficiency and do not have an increased need for carnitine. Although there are some theoretical points favouring potential ergogenic effects of carnitine supplementation, there is currently no scientific basis for healthy individuals or athletes to use carnitine supplementation to improve exercise performance.
O J Heinonen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Sports medicine (Auckland, N.Z.)     Volume:  22     ISSN:  0112-1642     ISO Abbreviation:  Sports Med     Publication Date:  1996 Aug 
Date Detail:
Created Date:  1996-12-19     Completed Date:  1996-12-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8412297     Medline TA:  Sports Med     Country:  NEW ZEALAND    
Other Details:
Languages:  eng     Pagination:  109-32     Citation Subset:  IM    
Department of Clinical Chemistry, Turku University Hospital, Finland.
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MeSH Terms
Body Composition
Carnitine / administration & dosage,  metabolism*,  physiology
Exercise / physiology*
Food, Fortified
Muscle, Skeletal / metabolism
Physical Education and Training
Pyruvate Dehydrogenase Complex / metabolism
Reg. No./Substance:
0/Pyruvate Dehydrogenase Complex; 541-15-1/Carnitine

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