Running 3000 meters is a long-distance running. It is ok to drink some glucose when running 400 meters, because you need energy immediately, but when running 3000 meters, the glucose may be used up quickly, because glucose can be absorbed and utilized without digestion, and glucose can quickly raise blood sugar, so your body will be in a state of insufficient energy at this time. At this time, because the body needs to mobilize the lactic acid in the muscles to be further converted into energy, the muscles contract violently, especially the abdomen, which can make the lower part of the abdomen move up, thus causing upwelling and vomiting. In fact, long-distance running should eat foods with high carbohydrate content, so as to continuously supply energy to the body.