1. Enhance myocardial function When people exercise in water, all organs participate in it, consuming more energy and accelerating blood circulation, thus providing more nutrition for the exercise organs. The acceleration of blood speed will increase the load on the heart, make the heart beat faster and contract strongly. People who swim regularly have excellent heart function. The average person's heart rate is 70-80 beats per minute, and the stroke output is 60-80 ml. Frequent swimmers' heart rate can reach 50-55 beats/min, many excellent swimmers can reach 38-46 beats/min, and the stroke output is as high as 90- 120ml. When swimming, the role of water makes it easy for limb blood to flow back to the heart and accelerate the heart rate. Long-term swimming will obviously increase the activity of the heart, contract strongly, increase the thickness and elasticity of the blood vessel wall, and increase the stroke output. Therefore, swimming can exercise a strong heart. 2. Enhance resistance. The water temperature in the swimming pool is often 26 to 28 degrees. Soaking water dissipates heat quickly and consumes a lot of energy. In order to supplement the heat emitted by the body as soon as possible and meet the needs of cold and heat balance, the nervous system reacts quickly, accelerating the metabolism of the human body, enhancing the adaptability of the human body to the outside world and resisting the cold. People who often take part in winter swimming are not easy to catch a cold because of the improvement of body temperature regulation function, and can also improve the endocrine function of human body, especially the function of pituitary gland, thus improving the resistance and immunity to diseases. 3. When swimming to lose weight, 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 calories. 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 running in a standard swimming pool for 20 minutes is equivalent to running at the same speed 1 hour on land, and the heat consumed by staying in water with 100 minutes is as high as 100 kcal, which is equivalent to being in air with the same temperature. It can be seen that water sports make many people who want to lose weight get twice the result with half the effort, so swimming is one of the most effective fitness exercises. 4. Bodybuilders usually use the buoyancy of water to lie prone or supine in the water when swimming, so that the whole body can be relaxed and stretched, so that the body can develop comprehensively, symmetrically and harmoniously, and the muscle lines are smooth. Exercise in water reduces the impact of the ground on bones, reduces the probability of bone aging, and the joints are not easy to deform. The resistance of water can increase people's exercise intensity, but this kind of intensity is very soft, which is different from the equipment training on land. It is easy to control the training intensity in aerobic area, and it will not grow stiff muscle blocks, which can make the whole body lines smooth and beautiful. 5. Strengthening lung function mainly depends on the lung, and the strength of lung function is determined by the strength of respiratory muscle function. Exercise is one of the effective means to improve and increase vital capacity. According to the measurement, when swimming, people's chest is under the pressure of 12- 15 kg. Cold water stimulates muscle contraction, making it difficult to breathe, forcing people to breathe hard, increasing the depth of breathing, and making the amount of oxygen inhaled meet the needs of the body. The average person's vital capacity is about 3200ml, and the breathing difference (the difference between the expansion and contraction of the chest circumference at the maximum inhalation and exhalation) is only 4-8 cm. The maximum oxygen uptake during strenuous exercise is 2.5-3 liters/minute, which is 10 times higher than that at rest. The swimmer's vital capacity can be as high as 4000-7000ml, the breathing difference can reach 12- 15cm, and the maximum oxygen uptake during strenuous exercise is 4.5-7.5 liters/min, which is 20 times higher than that at rest. Swimming makes people develop respiratory muscles, increase chest circumference, increase vital capacity and open more alveoli when inhaling, which is very beneficial to health. 6. When the skin care person swims, water washes the skin, sweat glands and fat glands, which plays a good massage role, promotes blood circulation and makes the skin smooth and elastic. In addition, when exercising in water, it greatly reduces the irritation of salt in sweat to the skin. The benefits of swimming to human health are not only the same as many sports, but also have a certain therapeutic effect on many chronic diseases, and have some unique therapeutic values. The main reasons are as follows: (l) Swimming is a sports event in a good natural environment where sunshine, air and cold water are integrated, so that all the curative effects of sunshine bath, air bath and cold water bath are concentrated on people. (2) Swimming is a systemic exercise, so its treatment of diseases is also a comprehensive and systematic treatment. Swimming can enhance the function of human nervous system, improve blood circulation, improve digestion and absorption of nutrients, thus enhancing physical fitness, enhancing resistance to diseases and achieving good therapeutic effects. (3) Swimming can enhance the functions of human organs and systems. Through swimming, patients with chronic diseases can enhance the functions of underdeveloped organs and systems, restore and enhance the functions of weak organs and systems, and thus treat diseases. (4) Swimming exercise can not only cultivate sentiment, temper will, and cultivate the spirit of fighting against nature, but also enable patients to establish confidence in overcoming diseases and overcome negative psychology of fear and worry about diseases, so it is very conducive to healthy rehabilitation and treatment of diseases. (5) Enhance myocardial function (6) Enhance resistance (7) Lose weight (8) Bodybuilding figure (9) Enhance lung function (10) Skin care is completed. I hope it will help the landlord.