Long-distance running exercise consumes heat energy, and the amount of heat energy consumed is directly proportional to the distance of long-distance running. For example, when running 10,000 meters, the energy consumption of exercise can reach about 750 calories, and when running a marathon, the energy consumption can reach 2,500 calories. The total amount of sugar stored in the human body is about 300~400 grams, and the calorific value after all oxidation is only 1200~1600 calories. Therefore, when participating in some long-term strenuous exercise on an empty stomach, a large amount of sugar stored in the body may be consumed. A hypoglycemic reaction occurs, with symptoms such as dizziness and weakness. Generally, long-distance running enthusiasts run early in the morning. Since they have to leave time for washing up and having breakfast after running, the running time should not be long. Generally, the running distance is about 1000, 2000, 3000 or 5000 meters. Such a distance consumes little heat energy, which is good for the body. The storage is sufficient for use and will not cause hypoglycemic reactions. Therefore, such long-distance running on an empty stomach will not cause any "disease".

As for whether you can eat before running, such as drinking some gruel or milk, it depends on your personal habits. Some people are used to running with an empty stomach after getting up. They don’t feel any discomfort after running, and they don’t need to eat. However, some people feel that they feel more energetic after eating a small amount, so they can eat less before running. However, you must be careful not to eat too much before exercise, and do not drink a lot of water, because running after eating too much will make the gastrointestinal tract full and cause the diaphragm to rise, affecting breathing during long-distance running. Moreover, not only the digestion of food Poor absorption causes food to oscillate in the stomach, which can also cause nausea, abdominal pain, and even vomiting. Generally, the total amount of food eaten before running should not exceed about 500 cubic centimeters.