Bone mineral density is the mineral density of bone, which is the indicator of bone quality and bone strength. Decrease in bone mineral density suggests osteoporosis. There are many reasons for osteoporosis, such as age, lack of exercise, long-term malnutrition, insufficient intake of calcium-rich foods, etc. Age is a very important factor, regardless of men and women, after the age of 35-40 years, bone mineral density will have a tendency to decline, so it is necessary to pay attention to bone mineral density in time. Exercise is also a very important factor. Studies have shown that with appropriate increase in exercise, patients’ bone density can be enhanced and improved. Patients with declining bone mineral density should undergo a bone mineral density examination to determine whether osteoporosis exists and to treat it accordingly.