If the exercise is too intense or lasts too long, or the vitamins and minerals necessary for the body to decompose lactic acid are insufficient, then the lactic acid in the body cannot be treated in time, leading to the accumulation of lactic acid. Too much lactic acid will make weakly alkaline body fluids acidic, which will affect the smooth absorption of nutrients and oxygen by cells and weaken the normal function of cells. Muscle with lactic acid accumulation will contract, thus squeezing blood vessels, making blood flow poor, leading to muscle aches, chills, headaches, top-heavy feelings and so on.