Running for the purpose of losing weight should not be less than 20 minutes, and the speed should be slower to keep breathing evenly. A 20-minute jog can not only exhaust a lot of glycogen in the body, but also make use of fat in the body. Moreover, because jogging is not very intense, it will not make the body too hypoxic, so it will help the consumption of fat, thus achieving the goal of losing weight.

The study of exercise biochemistry found that within 5 minutes after running, the heart adjusted to the physical exercise, the heartbeat was obviously accelerated, and the heart pumped more blood, but the degree was uneven, which was called "heart adaptation period". After running for 5 minutes, the heart has adapted, the heartbeat is strong, and the blood is pumped evenly, which can be adjusted at any time according to the amount of exercise.

Within 20 minutes of running, glycogen stored in the body is the main source of exercise energy, especially muscle glycogen and liver glycogen, because sugar can be decomposed into carbon dioxide and water under aerobic conditions, releasing a lot of energy. After running for 20 minutes, most of the glycogen is consumed, and the main source of energy is converted into body fat.

When fat is used passively, it is first decomposed into glycerol and fatty acids. Glycerol can be directly oxidized to provide energy, while fatty acids are converted into acetyl coenzyme A, and then some of them are converted into sugar to provide energy. Because of the high oxygen demand for fat energy supply, when the running intensity reaches the level of hypoxia, it is impossible to provide energy by oxidizing fat.

It should be noted that in the 1 month of long-distance running, the weight will increase slightly due to the increase of appetite, but the weight will drop rapidly in the second month. If you stop running in order to lose weight, you should reduce the amount of exercise and exercise time day by day to avoid causing "rebound obesity".