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Effects of carbohydrate feedings on plasma free tryptophan and branched-chain amino acids during prolonged cycling.

Abstract

Brain serotonin (5-hydroxytryptamine, 5-HT) has been suggested to be involved in central fatigue during prolonged exercise. Changes in the ratio of plasma free tryptophan (free Trp) to branched-chain amino acids (BCAA) are associated with altered brain 5-HT synthesis. The purposes of this study were to describe systematically the effects of prolonged exercise on changes in plasma free Trp and BCAA and to examine the effects of carbohydrate (CHO) feedings on these same variables. Eight well-trained men [VO2max = 57.8 (SE 4.1) ml kg-1 min-1] cycled for up to 255 min at a power output corresponding to VO2 at lactate threshold (approximately 68% VO2max) on three occasions separated by at least 1 week. Subjects drank 5 ml kg-1 body wt-1 of either a water placebo, or a liquid beverage containing a moderate (6% CHO) or high (12% CHO) concentration of carbohydrate beginning at min 14 of exercise and every 30 min thereafter. Exercise time to fatigue was shorter in subjects receiving placebo [190 (SE 4) min] as compared to 6% CHO [235 (SE 10) min] and 12% CHO [234 (SE 9) min] (P < 0.05). Glucose and insulin decreased in the placebo group, and free Trp, free-Trp/BCAA, and free fatty acids increased approximately five- to sevenfold (P < 0.05). These changes were attenuated in a dose-related manner by the carbohydrate drinks.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

,

Department of Exercise Science, School of Public Health, University of South Carolina, Columbia 29208.

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Source

MeSH

Adult
Amino Acids, Branched-Chain
Bicycling
Blood Glucose
Body Temperature
Dietary Carbohydrates
Dose-Response Relationship, Drug
Exercise
Exercise Test
Fatty Acids, Nonesterified
Heart Rate
Humans
Insulin
Lactates
Male
Oxygen Consumption
Pulmonary Gas Exchange
Tryptophan

Pub Type(s)

Clinical Trial
Controlled Clinical Trial
Journal Article

Language

eng

PubMed ID

1483439

Citation

Davis, J M., et al. "Effects of Carbohydrate Feedings On Plasma Free Tryptophan and Branched-chain Amino Acids During Prolonged Cycling." European Journal of Applied Physiology and Occupational Physiology, vol. 65, no. 6, 1992, pp. 513-9.
Davis JM, Bailey SP, Woods JA, et al. Effects of carbohydrate feedings on plasma free tryptophan and branched-chain amino acids during prolonged cycling. Eur J Appl Physiol Occup Physiol. 1992;65(6):513-9.
Davis, J. M., Bailey, S. P., Woods, J. A., Galiano, F. J., Hamilton, M. T., & Bartoli, W. P. (1992). Effects of carbohydrate feedings on plasma free tryptophan and branched-chain amino acids during prolonged cycling. European Journal of Applied Physiology and Occupational Physiology, 65(6), pp. 513-9.
Davis JM, et al. Effects of Carbohydrate Feedings On Plasma Free Tryptophan and Branched-chain Amino Acids During Prolonged Cycling. Eur J Appl Physiol Occup Physiol. 1992;65(6):513-9. PubMed PMID: 1483439.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of carbohydrate feedings on plasma free tryptophan and branched-chain amino acids during prolonged cycling. AU - Davis,J M, AU - Bailey,S P, AU - Woods,J A, AU - Galiano,F J, AU - Hamilton,M T, AU - Bartoli,W P, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - 513 EP - 9 JF - European journal of applied physiology and occupational physiology JO - Eur J Appl Physiol Occup Physiol VL - 65 IS - 6 N2 - Brain serotonin (5-hydroxytryptamine, 5-HT) has been suggested to be involved in central fatigue during prolonged exercise. Changes in the ratio of plasma free tryptophan (free Trp) to branched-chain amino acids (BCAA) are associated with altered brain 5-HT synthesis. The purposes of this study were to describe systematically the effects of prolonged exercise on changes in plasma free Trp and BCAA and to examine the effects of carbohydrate (CHO) feedings on these same variables. Eight well-trained men [VO2max = 57.8 (SE 4.1) ml kg-1 min-1] cycled for up to 255 min at a power output corresponding to VO2 at lactate threshold (approximately 68% VO2max) on three occasions separated by at least 1 week. Subjects drank 5 ml kg-1 body wt-1 of either a water placebo, or a liquid beverage containing a moderate (6% CHO) or high (12% CHO) concentration of carbohydrate beginning at min 14 of exercise and every 30 min thereafter. Exercise time to fatigue was shorter in subjects receiving placebo [190 (SE 4) min] as compared to 6% CHO [235 (SE 10) min] and 12% CHO [234 (SE 9) min] (P < 0.05). Glucose and insulin decreased in the placebo group, and free Trp, free-Trp/BCAA, and free fatty acids increased approximately five- to sevenfold (P < 0.05). These changes were attenuated in a dose-related manner by the carbohydrate drinks.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0301-5548 UR - https://www.unboundmedicine.com/medline/citation/1483439/Effects_of_carbohydrate_feedings_on_plasma_free_tryptophan_and_branched_chain_amino_acids_during_prolonged_cycling_ L2 - https://medlineplus.gov/exerciseandphysicalfitness.html DB - PRIME DP - Unbound Medicine ER -