The hazards of hypoglycemia are as follows: First, when hypoglycemia occurs, it leads to a significant increase in the secretion level of hormones that elevate blood sugar in the body, triggering an increase in blood sugar reactivity and intensifying the magnitude of blood sugar fluctuations. Second, when hypoglycemia occurs, the sympathetic nerve excites, the heart rate accelerates, and the oxygen consumption of the heart muscle increases, which easily induces adverse cardiac events, such as myocardial infarction, heart failure and arrhythmia. Third, hypoglycemia causes dizziness, general weakness, coma in serious cases, increases the probability of falling, easy to fracture, and even hypoglycemic coma and death. Fourth, long-term repeated hypoglycemia will bring irreversible chronic damage to the brain and a series of neurological symptoms, such as abnormal personality, senile dementia and reduced ability to take care of oneself, which in turn leads to increased difficulty in blood sugar control.