ABSTRACT
This chapter reports on various single amino acids that describe effects on physical performance and presents metabolic processes of interest to exercise. Arginine is known to influence several metabolic parameters important to exercise. Arginine supplementation to reduce ammonia toxicity has been demonstrated in animal models, where toxic doses of ammonia were produced by ammonium salts or excessive amino acid intake. Animal studies have shown that aspartic acid administration can reduce ammonia blood levels after exercise. Leucine, isoleucine, and valine make up the indispensable branched-chain amino acids. Ornithine is similar to arginine and lysine in structure and function, with the exception that ornithine is not incorporated into proteins. Like arginine, ornithine infusion can release growth hormone in humans. Like arginine, ornithine is an amino acid involved in the urea cycle. In animal studies, ornithine (alone or in combination with other amino acids, especially aspartic acid) has been shown to reduce ammonia toxicity or blood levels in experimental situations.
