Leg cramps are a symptom, not a disease, there are many reasons for leg cramps, the common reasons are as follows: 1, excessive exercise, long time exercise, such as long-distance running, soccer, etc. can lead to leg muscle spasm, thus leg cramps. 2, cold stimulation, when the leg muscles are cold stimulation will lead to leg muscle contraction, thus leg cramps. 3, calcium deficiency, when the blood calcium ion concentration is reduced muscle excitement, thus leg cramps. 4, lower limb vascular disease, when the lower limb arteries are blocked, such as lower limb atherosclerosis occlusive disease, leg cramps. The actual leg muscle spasm can be caused by the lowering of the calcium ion concentration in the blood. 4, lower limb vascular disease, when the lower limb arteries are blocked, such as lower limb atherosclerosis occlusive disease, the leg nerve muscle ischemia will appear leg muscle spasm, the symptoms of cramps.