Sugar, fat will not be consumed until 30 minutes later. Many people take this as the bible and force themselves to run for more than 30 minutes in order to lose weight. In fact, this is a widely circulated rumor. Today, we will talk about this issue from the perspective of energy metabolism. The conclusion is written first: as long as you start running, sugar and fat will participate in energy supply, but the ratio is different. About 20 to 30 minutes later, fat participates in energy supply gradually. Image source: Zhankuhailuo 1. Sugar and fat do not work independently. There are three main nutrients in the human body that participate in energy supply. Sugar, fat, and protein. Protein participates in energy supply during exercise, so we ignore it for the time being. The energy supply system of the human body is by no means an independent system. Sugar and fat actually work together. Glycogen provides energy at a faster rate, while fat provides energy at a slower rate. Therefore, under normal circumstances, short-term, high-intensity exercise is mainly powered by glycogen, because it needs fast energy supply, and fat is too late to break down; while long-term, medium-to-low-intensity exercise, generally consumes fat, glycogen It also consumes a certain proportion, so except for the kind of high-explosive sports in a very short time (such as a 50m sprint), there is almost no independent energy supply. Therefore, from the perspective of aerobic exercise, the human body’s energy supply does not have a priority relationship, it is just a change in proportion. For example, sugar is like cash in people’s hands. It is not much but can be paid at any time. Fat is like deposits people put in the bank. You don’t want to swipe your bank card until you have spent all your money, right? For the kind of long-term expenditure (such as monthly loan repayment), it is naturally better to use bank cards. Image source: Zhankuhailuo 2. After about 20 minutes of running, the proportion of fat energy supply increases. During long-distance running, sugar and fat not only participate in energy supply at the same time, but with the increase of time, the proportion of their participation also changes dynamically. Research It was found that generally speaking, after 20 to 30 minutes, the amount of fat oxidation and the rate of energy supply began to increase rapidly. Therefore, for that sentence, a more accurate statement should be that after running for 30 minutes, it is more conducive to fat consumption. So does this also mean that you must exercise for more than 30 minutes to have the effect of reducing fat? In fact, it is not, but the effect is better. For people with fat reduction goals, the easiest thing is to keep in mind a law, which is the law of conservation of energy. As long as exercise will consume energy, and as long as the energy consumed is greater than the energy taken in, it can achieve the effect of weight loss. For runners, you should still do what you can, step by step, and don’t force yourself to reach the 30-minute goal, otherwise it may cause unnecessary harm to the body. 3. Compared to running time, heart rate is more important. In order to achieve the best fat loss effect during aerobic exercise, the most important thing is that the heart rate should reach an appropriate level. There are two simple formulas here: maximum heart rate=220-age; best heart rate=(60%~80%)*maximum heart rate. When the human body is in this heart rate range, fat participates in the maximum energy supply, which is the most suitable exercise intensity for bodybuilders. You can also calculate your most suitable exercise heart rate, which can be used as a reference for exercise intensity during running. All in all, for runners with fat reduction needs, you must plan the appropriate exercise time and exercise intensity when making your own running plan. This has a multiplier effect for having a healthy body.