Foot cramps at night are mainly caused by calcium deficiency, be alert to bone and joint diseases, osteoporosis, cardiovascular disease, etc.. 1. Bone and joint diseases: teenage leg cramps are mostly caused by calcium deficiency, the lack of calcium can cause bone and joint dysplasia, which is easy to cause shortness, not easy to grow taller, and may also lead to rickets, chicken breast, funnel chest, costochondritis, chondritis and other diseases. 2. Osteoporosis: middle-aged and elderly people, due to the reduction of hormones, resulting in an increase in osteoclasts, osteoblasts decrease, resulting in accelerated bone loss, decreased calcium absorption, the body is gradually in a state of calcium deficiency, which can lead to leg cramps at night. 3. Cardiovascular disease: calcium can play a role in relaxing blood vessels and smooth muscle, after the lack of calcium, blood vessels and smooth muscle can not be relaxed, it is very easy to trigger hypertension, arrhythmia, manifested as dizziness, palpitations, chest tightness, precordial discomfort. There may be other reasons for foot cramps at night, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.