The purpose of measuring blood glucose in the morning is generally to measure fasting blood glucose, need to fast for 8 to 10 hours before the test, if the fasting time of 8 to 10 hours, 5 o’clock blood glucose test is also accurate. If you want to measure fasting blood glucose at 5 a.m., you need to fast for 8 to 10 hours before measurement, and you can start fasting and water fasting from 7 p.m. to 9 p.m.. Measuring blood glucose at 5 a.m. may have an effect on the detection of the Sumuje response and the dawn phenomenon. Dawn phenomenon refers to the control of blood glucose within the normal range at night, and the increase in fasting blood glucose in the early morning due to the secretion of glucagon around dawn in the absence of hypoglycemia at night. The Sumuje effect refers to the phenomenon of hypoglycemia at night and hyperglycemia in the early morning fasting. You can consult your doctor for more details about the specific precautions of blood glucose measurement and standardize the operation to avoid errors.