Cramps are clinically known as muscle spasms and can be caused by environmental factors, calcium deficiency, lactic acid accumulation and epilepsy. 1. Environmental factors: when the temperature suddenly changes or the temperature suddenly drops, muscle tremors or muscle spasms can occur. 2. Calcium deficiency: Because calcium ions play a very important role in the process of muscle contraction. When the calcium ion in the blood is lower than normal, the muscle will be easily excited, resulting in muscle spasm. 3. Lactic acid accumulation: this is because muscles constantly squeeze blood vessels during contraction and relaxation, which will take away metabolites from the body. However, if the blood flow is poor, the lactic acid produced in the body cannot be taken away and decomposed by the blood, and deposited in the muscles, the symptoms of muscle spasm will occur. 4. Epilepsy: When epilepsy exists in a patient, symptoms such as cramps, incontinence, and impaired consciousness occur due to abnormal excitation of the central nervous system. The presence of cramps, should be timely to the hospital, under the guidance of a professional physician for appropriate treatment, so as not to delay the condition.