Fasting blood sugar testing generally requires a fasting period of more than eight hours. This means that after 10 PM the night before the test, you should not eat or drink, and you should rest quietly. Blood should be drawn for testing after 6 AM the next morning to get an accurate fasting blood sugar reading.
If you did not rest well the night before, such as experiencing poor sleep or staying up late, the secretion of certain hormones that counteract insulin, like cortisol and renal hormones, may increase. The elevated levels of these hormones can cause fasting blood sugar levels to be generally higher, which does not accurately reflect the true blood sugar level. To get an accurate fasting blood sugar measurement, ensure you fast for eight hours and maintain a stable emotional state.
Therefore, it is generally required that you avoid consuming overly greasy or high-protein foods and refrain from drinking large amounts of alcohol the day before the test. The alcohol content in the blood can directly affect the test results. Do not eat anything after 8 PM the night before the test. Additionally, avoid fear-induced vasoconstriction that makes blood drawing more difficult. Excessive tension can also lead to elevated fasting blood sugar levels.