In Blood it occurs in the form of its salts (lactates) when glycogen is Broken down in muscle; it can be reconverted to glycogen in the liver. Stiffness and soreness after prolonged heavy exercise are due to accumulated lactic acid in the muscles.

• 当乳酸盐破坏肌肉中肝醣的产物时,血液中就会出现乳酸;而在肝脏里它又可以转变成肝醣。长时间强量运动后会感到肌肉僵硬和酸痛,就是肌肉中积累的乳酸引起的。