You generally have to fast for 8 to 12 hours before blood work. During this fasting period, you should avoid eating or drinking anything except plain water. Other activities such as chewing gum, smoking, and exercising should also be avoided as they can affect the test results. The exact fasting duration can vary depending on the specific blood test, so always follow your doctor's instructions. Scheduling the blood test in the morning is often recommended so that most of your fasting occurs while you sleep. Drinking water is encouraged to stay hydrated, which helps make the blood draw easier. Not all blood tests require fasting, so if unsure, confirm with your healthcare provider whether fasting is necessary for your specific test.
