Factors that can cause elevated fasting blood glucose include physiological factors and pathological factors, such as strenuous exercise, diabetes and other factors. 1. Physiological factors: Strenuous exercise, emotional stress and other factors caused by sympathetic nerve excitation and stress can cause fasting blood glucose. 2. Pathological factors: ① various types of diabetes mellitus; ② elevated intracranial pressure, such as intracranial hemorrhage, cranial trauma, etc.; ③ hyperglycemia due to dehydration, such as vomiting, diarrhea and hyperthermia, etc. can also increase blood glucose; ④ endocrine diseases: such as hyperthyroidism, pancreatic islet α-cell tumors, etc.; ⑤ hepatic glucose elevation: such as severe liver disease, cirrhosis and so on. It is recommended to consult a doctor in time when fasting blood glucose is elevated.