It is best to stick to it once a day for more than 30 minutes. Because when you start exercising, the first thing you consume is liver glycogen and muscle glycogen, that is, the sugar stored in the liver and muscles. After about half an hour, they are almost used up. At this time, you start to consume body fat. But this does not mean that the longer the time, the better, because the average person can bear a limited amount of exercise, and too long exercise will hurt the body. It usually takes an hour or two to start. In addition, swimming and walking are the same. Comparatively speaking, I think walking after dinner is better. The only thing to note is that you have to walk fast enough. Running is the method that some scientists disapprove of the most, because it will not only bring great burden to your body, but also make the weight loss effect even more unsatisfactory.