Many middle-aged and elderly people usually pay attention to health care, but they are told that their blood sugar exceeds the standard or they suffer from diabetes during physical examination. In fact, chronic diseases do not occur suddenly. When blood sugar is high, a warning will be issued more or less through the body. As the saying goes, "When a person grows old, their legs age first." During the process of aging, the legs of the human body first undergo changes. It can be said that the legs and feet are the "blood glucose meter" of the human body. When blood sugar exceeds the limit, the legs and feet may release the following signals: 1. The wound is not easy to heal. Wound healing requires cells near the wound to continuously divide and grow new cells, while also requiring immune cells in the blood to function to prevent the invasion of viruses and bacteria. However, high blood sugar can disrupt the body's originally "comfortable" environment, and even cause vascular disease and metabolic abnormalities, making it difficult for wounds to receive sufficient nutrition and self repair ability, making it difficult to heal. In addition, the immunity of elderly patients with diabetes is inherently poor. Improper treatment may lead to repeated bacterial infection of the feet, which ultimately leads to long-term wound healing. 2. "Sugar spots" appear. "Sugar spot" is also called "pretibial sugar spot", which is mostly seen in male patients with diabetes. It is mainly manifested as some irregular brown spots on the front of the lower leg. Mainly due to sustained hyperglycemia leading to dysfunction of endothelial cells, as well as capillary hypertension and poor protein metabolism, resulting in insufficient blood flow and malnutrition of the skin. Once there is trauma that stimulates the anterior tibia of both lower limbs, symptoms such as skin erythema, blisters, and erosion may appear. 3. numbness in the legs and feet. Long term hyperglycemia can cause adverse stimulation to the inner walls of blood vessels, leading to stiffness, hindering normal blood circulation, and causing numbness in the legs and feet. Some patients with diabetes will also have peripheral neuropathy with the aggravation of their condition, which will also lead to numbness of lower limbs, and with the passage of time of neuropathy, the symptoms will become more and more serious. 4. Skin itching. Excessive blood sugar can lead to the production of more inflammatory factors in blood vessels, damaging peripheral nerve endings, and resulting in a series of discomfort symptoms, such as skin itching. This type of itching mainly occurs in hands and feet, feeling like ants crawling on the skin, and often becomes more pronounced at night. Skin itching not only affects daily life and work, but also reduces sleep quality. A small number of patients experience pain hypersensitivity or decreased sensation. 5. Skin cracking. People with long-term high blood sugar will also have higher osmotic pressure in their bodies. The skin blood vessels are in an dilated state, and the water in the tissue will slowly transfer to the bloodstream. Some of the body fluids will be lost from the skin, causing dehydration and dryness of the skin. In addition, high blood sugar can also stimulate microcirculation regulation mechanisms, causing circulatory disorders in the skin itself, leading to dryness or cracking of the skin. Prevention of chronic diseases is more important than treatment. In daily life, middle-aged and elderly people should pay more attention to subtle changes in their legs and feet. If high blood sugar is not effectively controlled for a long time, it may cause very serious complications. If the above symptoms occur frequently, one should promptly seek medical attention at the hospital. (Le Xin She) (The author is Wang Fang, Chief Physician of the Cardiology Department of Beijing Hospital)