Oral branched-chain amino acids do not improve exercise capacity in McArdle disease

Neurology. 1998 Nov;51(5):1456-9. doi: 10.1212/wnl.51.5.1456.


To determine whether oral branched-chain amino acids (BCAAs) improve exercise capacity, six fasting patients with McArdle's disease were given a solution of BCAA (77 mg/kg) or a control noncaloric beverage 30 minutes before exercise. The BCAA meal tripled plasma BCAA levels, increased BCAA catabolism as indicated by greater exercise increases in plasma glutamine and alanine, but lowered mean peak free fatty acid levels and reduced exercise capacity in five of six patients. Lower work capacity may be attributed to a net reduction in muscle fuel availability after BCAA administration.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Administration, Oral
  • Adult
  • Amino Acids, Branched-Chain / administration & dosage
  • Amino Acids, Branched-Chain / blood
  • Amino Acids, Branched-Chain / therapeutic use*
  • Exercise / physiology*
  • Exercise Test
  • Female
  • Glycogen Storage Disease Type V / drug therapy*
  • Glycogen Storage Disease Type V / physiopathology*
  • Humans
  • Male
  • Middle Aged


  • Amino Acids, Branched-Chain