Leg cramps, also called muscle spasms, are involuntary cramps in the leg muscles that occur at night while sleeping and are painful, and the pain and stiffness of the leg caused by the cramps are difficult to relieve for a period of time. Leg cramps appear in the middle of the night, mostly due to the following reasons: First, cold, that is, due to the night blowing fans, and blowing air conditioning and long exposure of the legs, wind and cold stimulation and induced leg cramps; Second, basically due to calcium deficiency, when the body is lack of calcium, the muscles will be abnormally excited and induced cramps; Third, is due to excessive exertion, that is, during the day