It is best not to drink water in the morning of the physical examination, the physical examination must be in 8-12 hours fasting, need to check the biochemical indicators of liver function is required fasting, fasting means no water or food intake, in order to reduce the impact on the results of the physical examination, the morning need to fasting physical examination, you can drink 200ml of water in the morning after waking up, will not affect the results of the physical examination. The volume of blood in the body accounts for about 7%-8% of body weight, and for a person weighing about 60kg, the volume of blood is about 4200-4800ml. Having drunk 200ml of boiled water in the morning of the physical examination, there is about half an hour from home to the hospital and then to the blood collection, and the water drunk has been absorbed and penetrated into the tissues to participate in metabolism. In this half hour, 20-40ml of urine will be produced, and some of the fluid will be excreted through breathing and sweating. As long as the morning checkup does not exceed 200ml of water, it will have no effect on the blood markers.