ABSTRACT
The purpose of this study was to clarify the effects of amino acid supplementation on mental and physical stress during severe exercise. 20 male college students were assigned to amino acid treated group (group AA) and placebo treated group (group P), each containing 10 subjects, and performed 1600 m-run relay for 24 hours. Each subjects of AA group received 1 g of amino acid powder, containing 34% of branched-chain amino acid (BCAA), after each work bout. The score of rating of perceived exertion (RPE) and category rate of pain scale (CPS) for each work bout were recorded. Scoring of profile of mood states (POMS) was performed and blood samples were drawn at pre-, mid-, and post-session. Total running distance was similar in both groups. In group AA, compared with group P, (1) total score of RPE and CPS through 25 work bouts and plasma cortisol concentration (C) at post- was significantly lower, and (2) molar ratio of plasma free testosterone concentration (FTS) to C (FTS/C) at mid- was significantly greater. In group P alone, plasma BCAA concentration, FTS, FTS/C, and POMS score about ‘tension-anxiety’, ‘anger-hostility’ and ‘vigor’ decreased significantly over time. Our data suggest that BCAA administration during severe exercise may diminish mental or physical stress, inhibit FTS/C decrease and be effective in maintaining aggressive mentality.