Water pressure increases strength well in water more than 800 times larger density than air, so people are in the water pressure than the air pressure is much bigger, people standing in the water of chest, chest by the water pressure as high as 12 to 15 kg, if the water depth increases, the pressure will increase, breathe in the water have to overcome the water pressure, this will force inspiratory muscle in breathe in you need to use more power to complete breath, therefore, insist on swimming can increase the power of the well, expand the chest activities range, increase lung capacity, thus improve the respiratory function. The right ways to improve respiratory function in general, each action cycle on a breathing (namely the butterfly and breaststroke every stroke breathing, backstroke, freestyle two arms once each stroke breathing), and only in the first instant water face, in order to ensure the supply of oxygen when motion, without increasing resistance and cause the body to sink, head out of the water when inhaling must move fast and deep, this way of breathing can also help well enhanced strength and increase of vital capacity and thus make the swimmer's respiratory function was improved. Enhance the function of human digestive system 2 swimming can enhance the appetite, enhance the function of the digestive system. This is because water some of the physical properties of special function, because the water density and thermal conductivity is greater than air, so people 30 calories in water, also many times to stay in the same temperature of the heat release in the air, and swimming when the water temperature is generally lower than land temperatures, more body heat by conduction and loss of the water, since human energy consume when swimming, the body in order to keep the cooling and heat balance, the adjustment in the central nervous system, strengthened the heat production process, to mobilize the muscles and liver energy reserves in a large number of consumption, therefore ask quickly replenish energy, so the human digestive system will require food supply, The person that swim can appear hungry feeling, so the person often swims can promote appetite, enhance bodily metabolization ability, make digestive system function gets improvement and enhance. Improve the body's thermoregulatory function.3 people who swim regularly will not feel uncomfortable to the stimulation of cold water, because swimming exercise can improve the body's thermoregulatory function, and enhance the ability to adapt to the decrease of environmental temperature and the tolerance to cold. Swimming when people from the land of higher temperature low temperature of the water, low temperature makes the distribution in the surface of the sense organs - irritation of the skin receptors, and quickly to convey cold stimulation to produce hot center of the central nervous system, through the regulation of heat production center, cause muscle tension and reflective adrenal glands and the thyroid gland secretion, thereby strengthening the liver glycogen decomposition and oxidation, produced a lot of heat to supplement the calorie consumption and maintain body temperature. The person that often swims, its thermoregulatory system function is strengthened, the body produces hot process to get enhancement, to cold water stimulation not only can better adapt to, and the bear capacity to cold also increases greatly. Exercise the whole body muscle and joint 4 swimming is the muscle activity of the whole body, when swimming, the human body not only limbs movement, and from the neck to the foot, almost all the joints and muscles of the whole body to participate in sports, so that all the muscles, bones and joints of the whole body are exercised and balanced development. Because this holds to swim for a long time, the skeleton of each ministry of the crowd whole body is thicker and stronger, muscle is very developed.