Muscle acidity during exercise may be caused by certain physiological factors, or it may be caused by certain diseases such as colds and rheumatoid arthritis. 1. Physiological factors: In order to ensure that the body obtains a large amount of energy in a short period of time during exercise, the energy metabolism is dominated by anaerobic fermentation, which produces a large amount of lactic acid. The accumulation of lactic acid stimulates the sensory nerve endings, which are transmitted to the brain through the nerves, causing muscle soreness. 2. Colds: After a cold, the patient will have a fever, which leads to anaerobic respiration of the body muscles, resulting in the production of lactic acid, which is exacerbated by exercise, resulting in body aches and pains. 3. Rheumatoid arthritis: the patient is in a period of pathological activity, the synovial membrane of the joints and the surrounding tissues are edematous, and there are mucous changes in the connective tissue under the synovial membrane, which leads to muscle aches and pains. Due to physiological factors caused by muscle soreness, can be relieved by appropriate rest, massage and other ways to exclude physiological factors caused by the symptoms, it is recommended that patients go to the hospital in a timely manner, in accordance with the doctor’s instructions standardized treatment.