The time it takes for lactic acid buildup to disappear after exercise varies from person to person, usually taking two to three days, and in some people it may take five days to a week for it to disappear. When we carry out strenuous exercise, such as 100-meter race, in this case the cell is an anaerobic state, the way to produce energy is through anaerobic oxidation, the substance produced is lactic acid, lactic acid produced after the accumulation of the middle of the tissue, which will lead to lactic acid infiltrated parts of the production of acidity, this phenomenon is a normal phenomenon, after a period of time the human body metabolism, can be absorbed by the lactic acid. People with good physical condition can absorb the lactic acid in two or three days, and the symptoms are relieved. If people who do not exercise regularly or older people with poor physical condition, the recovery time is slower, and it may take five days to a week or so for the symptoms to gradually disappear.