As soon as you start exercising, you are burning calories from that moment on. The unit of heat can be joules or calories. Because the unit is too small, kilojoules or kilocalories (kcal) are commonly used as units at present. The calories consumed by muscle can be glycogen inside muscle, or energy released during aerobic metabolism of sugar, fat and protein.

Aerobic exercise refers to the exercise form in which muscle energy comes from the aerobic glycolysis process of sugar, fat and protein. In the process of aerobic exercise, glycogen in the body is used first, and when glycogen is exhausted, fat is consumed. The saying that "the fat burns out after 30 minutes" comes from this. But this time is not fixed. If you have less sugar in your body (such as skipping breakfast in the morning), it will be greatly shortened.

What you described about being soaked in the skin is not only ok, but also consumes a lot. The calories consumed are generally positively correlated with their own weight, exercise time and exercise intensity. If you have a large weight, high exercise intensity (high heart rate during exercise) and long exercise time, then you consume a lot of calories.