Long-distance running is characterized by consuming a lot of calories. Because I have been sleeping at night and fasting in the morning, the blood glucose is at a low level, and a lot of blood sugar needs to be consumed through a lot of activities. At this time, it is necessary to use glycogen stored in the liver to convert it into glucose for long-distance running.
If there is not much glycogen in the liver, glycogen and fat in other organs will be consumed. Liver glycogen is called for a long time, and the reserve is reduced, which will damage liver organs. The scientific method is to eat some food or drink some sugar water before long-distance running, which is beneficial to the supplement of calories.