最近科學家對中樞疲勞的探討有越來越高的興趣，目前大部分人較為熟知的影響因子之－為神經傳遞物質－血清素，當血清素濃度增加，將可能導致中樞疲勞反應發生。而血液中色胺酸與支鏈胺基酸濃度會影響血清素產生，間接影響中樞疲勞，可是關於上述機制的實驗證據正反不一。但最近開始有許多直接的證據支持血清素、色胺酸與支鏈胺基酸對中樞疲勞的影響。本文對支鏈胺基酸在中樞疲勞中所扮演的角色進行探討，提出建議的增補劑量與時間。根據本文獻探討結果：運動期間每隔15~20分鐘，補充達總劑量6~8g（大約以90m/kg Bw計算攝取量）的支鏈胺基酸，具有延緩中樞疲勞的功效，於運動表現上有正面的提昇，且銨離子濃度升高的情況不明顯。

There is an increasing interest in the mechanism behind central fatigue and at present we know that serotonin can induce central fatigue. The precursor of serotonin is tryptophan and the synthesis of serotonin in the brain is thought to be regulated by the blood supply of free tryptophan in relation to the branched-chain amino acids (BCAA) since these compete with tryptophan for transport into the brain. Studies in human subjects have shown that the plasma ratio of free tryptophan/BCAA increases during and, particularly, after sustained exercise. This would favor the transport of tryptophan into the brain and also the synthesis and release of serotonin which may lead to central fatigue. Attempts have been made to influence the serotonin level by providing BCAA to human subjects during different types of sustained heavy exercise. However, more discussions are needed to further clarify the effect of BCAA ingestion on central fatigue. This article is going to explore the researches about BCAA and central fatigue, and try to find out a suitable way to ingestion BCAA for the purpose of delaying central fatigue. According to the studies, the recommend dose of BCAA is 6~8g (90 mg/kg BW) and BCAA should be ingested during exercise.