Exercise strengthens metabolism, releases a lot of heat and makes people's body temperature rise. In order to regulate body temperature, sweat glands secrete sweat. Sweat takes away some body heat through transpiration. Sweating will take away the body's heat and a lot of water and some electrolytes. The weight difference reflected before and after sweating is mainly due to a large amount of water loss.

In the high temperature environment in summer, the body temperature rises faster, the sweat secreted by sweat glands increases, the branches carrying water become more, and the weight drops more. In addition, some people are prone to sweating even if they don't exercise because of their natural constitution or sweating. Therefore, it is somewhat biased to measure the effect of reducing fat only by sweating.

The effect of losing weight by exercise is not based on the amount of sweating, but mainly depends on the degree to which fat is converted into heat during exercise. Take sit-ups as an example. You did a lot of sit-ups soon, and you were so tired that you were sweating. But in this process, sit-ups mainly consume sugar to provide energy, and burning fat provides less energy, so you can't achieve the ideal fat-reducing effect.