Long-term calcium deficiency can cause lower blood calcium and form hypocalcemia. Calcium ions can reduce neuromuscular excitability, lower blood calcium will cause neuromuscular excitability to rise, easy to muscle spasm, the musculoskeletal system in the early stages of the toes or fingers numbness, sensory loss. Severe hypocalcemia can lead to spasms in the larynx, wrists, and even the ankles and bronchial areas, and can also induce seizures, and in severe cases, apnea, as well as predispose the patient to psychiatric symptoms such as irritability, depression, or symptoms of cognitive impairment. Decreased blood calcium also has an effect on the cardiovascular system, serious arrhythmia, ventricular fibrillation, heart failure, etc., the ECG is typically characterized by QT intervals, as well as a significant prolongation of the ST segment. There are also significant effects on the skeletal system. Chronic hypocalcemia causes osteoporosis and can leave the skin dry and inelastic. Severe lowering of blood calcium can also lead to symptoms such as nails breaking easily, loose teeth, and tooth loss.