(1) Because the resistance of water when swimming is much greater than that of air when moving on land, it will consume more heat. At the same time, the thermal conductivity of water is 24 times higher than that of air, and the water temperature is generally lower than that of air, which is also beneficial to heat dissipation and consumption. So swimming consumes much more energy than running and other land projects, so the effect of losing weight is more obvious.
(2) When carrying out weight-loss exercise on land, some obese people are overweight, which makes their bodies (especially lower limbs and waist) bear great gravity load, which reduces their exercise ability, makes them easy to get tired, greatly reduces their interest in weight-loss exercise, and can damage 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.
(3) When swimming, the buoyancy, resistance and pressure of water are excellent massages for the human body and can beautify the skin.
(4) Swimming is a systemic exercise, and the muscles of the back, chest, abdomen, buttocks and legs can be well exercised during swimming. Losing weight is also all-round.