People swim in the water, paddle with two arms, kick with two legs at the same time, and all the muscles of the whole body participate in sports, which can make the muscles of the whole body get a good exercise. In addition, when swimming, because the density (in other words, resistance) and heat transfer performance of water are greater than that of air (the heat transfer coefficient of water is 26 times greater than that of air, that is, at the same temperature, the human body can dissipate heat in water more than 20 times faster than in air, which can effectively consume heat), so the human body consumes more energy in water than on land. These energy supplies are supplemented by consuming sugar and fat in the body. Regular swimming can gradually remove excess fat from the body without getting fat.