Cramps generally refer to muscle spasms, which are spontaneous compulsory contractions of muscles. The typical performance of an attack is unbearable pain, which can last for several seconds or tens of seconds, and it is easy to have an attack in the middle of the night. Midnight leg cramps are usually related to cold stimulation, strenuous exercise, poor sleep, calcium deficiency and other factors: 1, cold stimulation: due to the low temperature at night, not covered with a good quilt, resulting in cold stimulation of the leg muscles, cramps in the middle of the night, can be manifested as leg pain; 2, strenuous exercise: if you have strenuous exercise before going to bed or overworked during the day, the whole body is in a state of tension, leg muscle contraction Too fast, local metabolites lactic acid increased, muscle contraction and relaxation is difficult to coordinate, thus appearing in the middle of the night leg muscle spasm; 3, poor sleep: lack of sleep can lead to the accumulation of local acidic metabolites, can cause muscle spasm. Sleep rest is too long, blood circulation slows down, so that carbon dioxide buildup, which can also lead to leg cramps. Poor sleep posture, such as prolonged supine lying with the quilt pressed against the foot, or prolonged prone lying with the foot against the bed, forcing certain muscles of the calf to be in a state of absolute relaxation for a long time, causing passive muscle cramps; 4. Calcium deficiency: calcium ions have a very important role in the contraction process of muscles. When the concentration of calcium ions in the blood is too low, it leads to muscle excitement and cramps. The main reason for leg cramps in the middle of the night for pregnant women is calcium deficiency. Teenagers grow rapidly and are also prone to calcium deficiency, which leads to leg cramps in the middle of the night; 5. Drug influence: If you take diuretics, morphine for pain, cimetidine for stomach problems, statins for lowering cholesterol or hormone drugs for asthma, etc., it may cause muscle cramps, so the probability of leg cramps in the middle of the night will be elevated.