Leg cramps may be caused by the following reasons: 1, it may be caused by excessive muscle strain, usually often standing and walking during the day, or often do strenuous exercise, resulting in muscle fatigue, so that at rest or at night, there will be leg cramps; 2, caused by cold, such as sleeping at night without covers, or in winter when the weather is too cold The lower extremity blood circulation can become poor, which can lead to cramps; 3, may be caused by calcium deficiency; 4, may be the lumbar spine disease compression of the nerve roots of the lower extremity, such as lumbar disc herniation, lumbar spinal stenosis and other diseases, compression of the nerve roots of the lower extremity, there will be abnormal nerve function and lead to leg cramps.