Bone density is a medical term that refers to the amount of bone mineral per unit volume. Calcium and phosphorus are the main components of bone minerals, and the more calcium and phosphorus that is deposited in the bones, the greater the bone density. The full name of bone density is bone mineral density, which is an important indicator to determine the strength of bones, age, gender, height and weight will affect the bone density. T-values are often used in clinical practice to determine whether bone density is normal. The normal range of T-value is between -1 and +1. If the T-value is lower than -2.5, it suggests that the patient’s bone quality is poor, and may be accompanied by severe osteoporosis, which is prone to fracture. In daily life, bone density can be improved by sun exposure, daily exercise or taking medication such as calcitonin under the guidance of a doctor to minimize calcium loss. If you experience any obvious discomfort, it is recommended that you go to the hospital immediately.