Document Detail


Beta-alanine supplementation in high-intensity exercise.
MedLine Citation:
PMID:  23075550     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Glycolysis involves the oxidation of two neutral hydroxyl groups on each glycosyl (or glucosyl) unit metabolised, yielding two carboxylic acid groups. During low-intensity exercise these, along with the remainder of the carbon skeleton, are further oxidised to CO(2) and water. But during high-intensity exercise a major portion (and where blood flow is impaired, then most) is accumulated as lactate anions and H(+). The accumulation of H(+) has deleterious effects on muscle function, ultimately impairing force production and contributing to fatigue. Regulation of intracellular pH is achieved over time by export of H(+) out of the muscle, although physicochemical buffers in the muscle provide the first line of defence against H(+) accumulation. In order to be effective during high-intensity exercise, buffers need to be present in high concentrations in muscle and have pK(a)s within the intracellular exercise pH transit range. Carnosine (β-alanyl-l-histidine) is ideal for this role given that it occurs in millimolar concentrations within the skeletal muscle and has a pK(a) of 6.83. Carnosine is a cytoplasmic dipeptide formed by bonding histidine and β-alanine in a reaction catalysed by carnosine synthase, although it is the availability of β-alanine, obtained in small amounts from hepatic synthesis and potentially in greater amounts from the diet that is limiting to synthesis. Increasing muscle carnosine through increased dietary intake of β-alanine will increase the intracellular buffering capacity, which in turn might be expected to increase high-intensity exercise capacity and performance where this is pH limited. In this study we review the role of muscle carnosine as an H(+) buffer, the regulation of muscle carnosine by β-alanine, and the available evidence relating to the effects of β-alanine supplementation on muscle carnosine synthesis and the subsequent effects of this on high-intensity exercise capacity and performance.
Authors:
Roger C Harris; Craig Sale
Publication Detail:
Type:  Journal Article     Date:  2012-10-15
Journal Detail:
Title:  Medicine and sport science     Volume:  59     ISSN:  1662-2812     ISO Abbreviation:  Med Sport Sci     Publication Date:  2013  
Date Detail:
Created Date:  2012-10-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8402440     Medline TA:  Med Sport Sci     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  1-17     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 S. Karger AG, Basel.
Affiliation:
Junipa Ltd, Newmarket, Suffolk, UK.
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