Cramps are clinically known as muscle spasms and can be caused by environmental factors, calcium deficiency, lactic acid accumulation, epilepsy, and so on. 1. Environmental factors: When there is a sudden change in temperature or a sudden drop in temperature, muscle tremors or muscle spasms may 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 the normal value, the muscles 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: Some epilepsies are characterized by myoclonic seizures, so cramps can also occur in epilepsy. When the symptoms of cramps appear, it is recommended to go to the regular hospital for examination to exclude pathological diseases. In normal life, pay attention to calcium supplement, avoid cold, moderate exercise, can help relieve cramps.