title: Plasma and urine carnitine concentrations in well-trained athletes at rest and after exercise. Influence of L-carnitine intake.
abstract: L-carnitine is essential to cellular energy production mainly because of its acyl- and acetyl-carrier properties. Athletes commonly take L-carnitine, which is thought to improve exercise performance. There are no reports on carnitine plasma concentrations and carnitine excretion in short-duration maximal exercise in well-trained athletes taking this substance. We measured plasma and urine carnitine concentrations before and 10 min after maximal treadmill ergometry in nine well-trained sportsmen with and without oral supplementation with 1 g L-carnitine. In athletes without L-carnitine intake, plasma free carnitine concentration decreased significantly from 45.2 +/- 5.3 to 41.6 +/- 5.0 mumol/l (mean +/- SD, p < 0.001) 10 min after exercise compared with baseline. In athletes with oral L-carnitine supplementation, plasma free carnitine concentration at baseline was 71.3 +/- 10.2 mumol/l and did not change after maximal exercise (71.8 mumol/l +/- 10.7 mumol/l). The elevated plasma concentration of free carnitine without decrease after maximal exercise in well-trained athletes taking L-carnitine could be important in view of the newly postulated direct vascular effects of L-carnitine in improving skeletal muscle performance.
authors.affiliation: Department of Internal Medicine, University Hospital, Basel, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Nüesch
authors.forename: M
authors.initials: M
authors.lastname: Rossetto
authors.forename: B
authors.initials: B
authors.lastname: Martina
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002331:Carnitine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D016022:Case-Control Studies; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology*; D006801:Humans; D012016:Reference Values; D012146:Rest; D013178:Sports Medicine
chemical_list: D002331:Carnitine