When swimming, the body is directly immersed in water, which not only has great resistance, but also has very good thermal conductivity and fast heat dissipation, so it consumes more heat. Like a boiled egg, the cooling rate in air is far less than that in cold water. Experiments show that the heat consumed by a person swimming in a standard swimming pool for 20 minutes is equivalent to swimming on land at the same speed 1 hour, and staying in water with 100 minutes is as high as 100 kcal, which is equivalent to being in air with the same temperature. In addition, swimming diet can avoid sports injuries of lower limbs and waist. When you exercise on land to lose weight, your body (especially lower limbs and waist) will bear great gravity load because of the heavier weight of obese people, which will reduce your exercise ability and make you tired easily, thus greatly reducing your interest in losing weight and damaging the joints and bones of lower limbs. When swimming in water, a considerable part of obese people's weight is borne by the buoyancy of water, which makes their lower limbs and waist much easier and greatly reduces the risk of joint and bone injury. It can be seen that water sports make many people who want to lose weight get twice the result with half the effort. Therefore, swimming is one of the most effective aerobic exercises to keep healthy.