Can I drink water before a fasting physical examination?

Nowadays, many people have begun to pay attention to their physical health and will go for regular physical examinations. However, many people do not know how to do a physical examination, such as why they need to fast? Can I drink water on an empty stomach? What tests require fasting? I believe many people don’t know the following questions. Now let me tell you whether you can drink water before a physical examination on an empty stomach?

Why fasting?

The fasting mentioned in the physical examination is not as popularly understood as skipping a meal. The fasting standard is 8-14 hours (overnight) without caloric intake. That is, the night before the physical examination, you should have a normal dinner according to your usual habits, but no midnight snack, and skip breakfast the next morning for the examination (even chocolate is not allowed!).

But you can't go without food or water for a long time. If you fast for more than 18 hours, your body will be in a state of hunger. When in a state of hunger, the comparison is no longer based on uniform standards, and the measured results cannot be used as a reference for diagnosis. For example, blood sugar and blood ketone bodies are greatly affected by hunger.

Therefore, it is necessary to grasp the reasonable fasting time. For example, the best time for fasting blood collection is between 8 and 9 in the morning, and no later than 9:30 at the latest. If it is too late, it will be affected by physiological and endocrine hormones. For example, blood sugar can decrease as the fasting time increases. If blood sugar decreases due to starvation for a long time, it will not only affect judgment but also may lead to the risk of hypoglycemia.

Which examination items can I drink water for?

1. You need to drink a lot of water:

You need to drink water before many ultrasound examinations, such as urinary bladder ultrasound examination, transabdominal gynecological ultrasound examination, and transabdominal prostate ultrasound examination. These examinations require holding urine to expand the bladder to facilitate the detection of lesions in the bladder, or to help ultrasound pass through the full bladder to observe the internal organs in the pelvic cavity.

2. You must not drink:

You must not drink water during painless (anesthetized) gastrointestinal endoscopy, because after anesthesia, it is easy to cause choking and suffocation.

3. You can drink some water during other examinations

Because everyone loses water at a different rate, it is best not to feel thirsty. Try not to drink other beverages, such as sugary fruit juice, milk, and tea, which will directly change the test indicators in the blood; and coffee, even black coffee, will affect the changes in hormone levels in the blood and affect blood biochemical indicators.