If there are frequent calf cramps at night, there are several reasons: 1. First, exclude the recent high-intensity physical exercise, because high-intensity physical exercise will lead to frequent muscle contraction, or too much sweating during exercise, resulting in excessive loss of electrolytes triggered by cramps. 2. This is a direct result of the lack of calcium and micronutrients. 3, seen in the lower extremity vascular disease, such as lower extremity arterial occlusion, lower extremity arteriosclerosis, lower extremity varicose veins, and even aortic coarctation, can also cause frequent cramps in the lower legs, mostly in elderly patients or people who often stand. 4, seen in the cold people, due to the cold stimulation of the local blood flow, and cause muscle cramps.