How many hours does it take to get a health certificate on an empty stomach?

Eight hours. You need an empty stomach when you apply for a health certificate. During routine physical examination, you must have an empty stomach for at least 8 hours before you can have a physical examination. It is best not to eat anything after 8 o'clock the night before. When doing health certificate examination, it is best to do it in the morning, and the examination results are more accurate.