Leg cramps are medically known as muscle spasms, and this disease occurs mainly because the muscles undergo tonic contraction, inducing pain in the legs of patients. The causes of nighttime cramps in the calf area are more: 1, fatigue, high-intensity physical exercise, mountain climbing during the day, resulting in the metabolism of the calf area, a large accumulation of lactic acid and failure to discharge in a timely manner, inducing patients to appear leg cramps. 2, cold, such as night sleep, prolonged blowing air conditioning or calf exposure, stimulated by wind and cold and induced cramps. 3, calcium deficiency If the patient’s body has a large amount of calcium deficiency, it will lead to abnormal excitement in the leg muscles and induce cramps in the legs. 4, disease, such as the most common is the lower limb varicose veins and induce cramps.