First of all, look at your sports performance today, 8 kilometers. If it is 8KM/H, it will take an hour. I don't know if you ran it all at once or in several times. According to the data you provided, I personally think that your running time is appropriate, but it should not be too long. It is recommended that the duration of an exercise should not exceed 45-60 minutes. It is recommended to jog 3~4 times a week to burn fat, which can be combined with a reasonable diet and not overeating. In addition, the effect of running alone may not be obvious, so you can add some other exercises, such as cycling and sit-ups. These are all ready-made equipment in the gym. The first month may not have too obvious effect, and even different systems may be a little fatter, but they will be thinner in the second or third month. Exercise is a good thing, so stick to it. Wish you good health.