Cramp is a symptom caused by the occurrence of spasmodic contraction of muscles, which can cause significant local pain. The following are the common clinical causes of cramps: 1. prolonged local cold and dampness lead to decreased blood circulation in the muscles, ischemia and hypoxia, and spasmodic contractions cause cramps, which can be quickly relieved by timely warmth or hot compresses to alleviate cramps; 2. prolonged strenuous activities lead to increased formation of lactic acid in muscle tissue and accumulation of local muscle cramps. The symptoms of local muscle cramps are caused by the accumulation of lactic acid. It is necessary to drink more water and rest with hot compresses to promote lactic acid metabolism and relieve symptoms; 3, due to increased demand for calcium, insufficient intake or excessive loss, resulting in lower blood calcium, causing increased excitability of muscle tissue and spasmodic contraction, which requires active calcium supplementation; 4, hypothyroidism or brain disease can also cause cramping symptoms.