Symptoms and manifestations of calcium deficiency in adults mainly involve the nervous system, cardiovascular system, skeletal system, etc., numbness of the hands and feet, panic and chest tightness, lumbago and back pain, and so on. 1. Nervous system: mild calcium deficiency can cause numbness of hands and feet, and some mild cramps of hands and feet, which can be relieved by resting for a while. 2. Cardiovascular system: Because calcium ions have a certain effect on cardiovascular electrophysiological activities, calcium deficiency can lead to a certain degree of cardiac arrhythmia, and in severe cases, it can lead to ventricular fibrillation, heart failure, and so on. 3. Skeletal system: Because calcium and bones are inseparable, calcium deficiency will affect the bones, osteoporosis is also easy to cause fractures, if calcium deficiency is very serious, the bones will have symptoms of pain, and there will be accompanying symptoms of lumbago and back pain. In addition to the above manifestations, calcium deficiency can also lead to other systemic lesions, early calcium deficiency if found in time, timely treatment of calcium supplementation, generally will not lead to serious consequences, so if you find the manifestations of calcium deficiency, you should immediately go to the hospital for examination and clarification.