SD rats were sampled and spiperone binding to serotonin2A receptors on brain and platelets were tested before and after a section training or long-term(3 weeks) intensive training using radiolabeled receptor assay. Results showed that there were significant increment of concentration of 5-HT in brain and decrease of 5-HT 2A R density in specific binding sites(B max ) on membranes of brain and platelets post acute intensive exercise. The downregulation of B max of 5-HT 2A R could be prevented by the supplement of BCAA+CHO during 3 weeks' intensive training. There was a positive effect on the delay of central fatigue with the supplement of BCAA+CHO during long-term intensive exercise.