Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 1995 Aug 1;486 ( Pt 3)(Pt 3):789-94.
doi: 10.1113/jphysiol.1995.sp020854.

Ingestion of Branched-Chain Amino Acids and Tryptophan During Sustained Exercise in Man: Failure to Affect Performance

Affiliations
Free PMC article
Clinical Trial

Ingestion of Branched-Chain Amino Acids and Tryptophan During Sustained Exercise in Man: Failure to Affect Performance

G van Hall et al. J Physiol. .
Free PMC article

Abstract

1. An increased uptake of tryptophan in the brain may increase serotoninergic activity and recently has been suggested to be a cause of fatigue during prolonged exercise. The present study, therefore, investigates whether ingestion of tryptophan or the competing branched-chain amino acids (BCAAs) affect performance. Ten endurance-trained male athletes were studied during cycle exercise at 70-75% maximal power output, while ingesting, ad random and double-blind, drinks that contained 6% sucrose (control) or 6% sucrose supplemented with (1) tryptophan (3 g l-1), (2) a low dose of BCAA (6 g l-1) or (3) a high dose of BCAA (18 g l-1). 2. These treatments greatly increased the plasma concentration of the respective amino acids. Using the kinetic parameters of transport of human brain capillaries, BCAA supplements were estimated to reduce brain tryptophan uptake at exhaustion by 8-12%, while tryptophan ingestion caused a 7- to 20-fold increase. Exercise time to exhaustion was not different between treatments (122 +/- 3 min). 3. The data suggest that manipulation of tryptophan supply to the brain either has no additional effect upon serotoninergic activity during prolonged exhaustive exercise or that manipulation of serotoninergic activity functionally does not contribute to mechanisms of fatigue.

Similar articles

See all similar articles

Cited by 20 articles

See all "Cited by" articles

References

    1. J Neurochem. 1977 May;28(5):1015-23 - PubMed
    1. J Neurochem. 1977 Jan;28(1):103-8 - PubMed
    1. Physiol Rev. 1983 Oct;63(4):1481-535 - PubMed
    1. Am J Physiol. 1985 Feb;248(2 Pt 2):R166-71 - PubMed
    1. Br J Pharmacol. 1985 Sep;86(1):33-41 - PubMed

Publication types

LinkOut - more resources

Feedback