For most blood tests that require fasting, the recommended fasting period is usually between 8 to 12 hours before the blood sample is taken. In some cases, fasting may be extended up to 14 hours depending on the specific test. During this fasting period, you should only drink water and avoid eating any solid foods or drinking any beverages containing sugar or calories. You should also avoid smoking, chewing gum, and vigorous exercise as these can affect test results. Typically, fasting is done overnight with the blood test scheduled in the morning to make it easier to fast while sleeping. Always follow specific instructions given by your healthcare provider, as fasting requirements can vary depending on the type of blood test being performed.