Generally speaking, it is recommended to swim for more than 30 minutes each time, preferably 45-60 minutes, at least twice a week. After swimming for 30 minutes, the proportion of fat energy supply reached the highest. If the swimming time is too long, it will not only consume too much protein, but also cause muscle loss, which will affect the next day's work, study and training. So 45-60 minutes is a better choice.
Extended data
Swimming health value:
1, improving cardiovascular system:
Swimming plays an important role in improving cardiovascular system. The stimulation of cold water can promote blood circulation through heat regulation and metabolism;
In addition, the pressure and resistance of water also play a special role in the heart and blood circulation. When swimming on the water, the water pressure on the body has reached 0.02-0.05 kg per square centimeter. When diving, with the increase of depth and the change of physical condition, the pressure will increase, and the acceleration of swimming speed will also increase the pressure load.
The muscle tissue of atria and ventricles can be strengthened, the volume of cardiac cavity can be gradually increased, and the beating times of the heart can be reduced, so that the activity of the heart can be preserved, but the whole blood circulation system can be improved, and the diastolic blood pressure increases and the systolic blood pressure decreases at rest, so the blood pressure value becomes more favorable.
2, improve the vital capacity:
Breathing mainly depends on the lungs, 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.
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. Swimming makes people develop respiratory muscles, increase chest circumference, increase vital capacity and open more alveoli when inhaling, which is very beneficial to health.
3, improve the function of the respiratory system:
One of the main characteristics of water is incompressibility. Because the density of water is more than 800 times higher than that of air, the pressure on people in water is far greater than that in air. This is also the reason why beginners have difficulty breathing in the water. As the pressure in the chest and abdominal cavity increases in water, it forces the respiratory muscles to breathe with greater strength. Therefore, regular swimming can increase the strength of respiratory muscles and improve the function of respiratory system.
4, the ability to improve the muscle system:
Swimming is a whole-body exercise, which can mobilize more muscle groups to participate in metabolism and energy supply than other sports. Although swimming can't build thick and bulging muscles, it can improve the strength and coordination of many muscles, especially the muscles of trunk, shoulder straps and upper limbs. Because swimming in water needs to overcome great resistance, and swimming is a periodic exercise, long-term exercise can improve muscle strength, speed, endurance and joint flexibility.
5. Mechanism of improving thermoregulation:
Because the temperature of water is generally lower than that of air, and the thermal conductivity of water is dozens of times stronger than that of air, people dissipate heat much faster in water than in air. Regular swimming can improve the ability of body temperature regulation, so as to be more able to withstand the changes of external temperature. Especially in winter swimming, this improvement is particularly obvious.
6, strengthen skin blood circulation:
In the process of swimming, due to the stimulation of water temperature, the body in order to ensure adequate temperature. Skin blood vessels play an important regulatory role. Stimulation of cold water can make skin blood vessels contract and prevent heat from spreading outward. At the same time, the body will intensify the generation of heat, dilate the blood vessels of the skin and improve the blood supply of the blood vessels of the skin, so that long-term exercise can strengthen the blood circulation of the skin.
When people swim, the water washes away 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.
7, enhance resistance:
The water temperature in the swimming pool is often 26 to 28 degrees, so soaking in 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 and increase the function of pituitary gland, thus improving the resistance and immunity to diseases.
8. lose weight:
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.
9, bodybuilding:
When swimming, people usually use the buoyancy of water to lie prone or supine in the water, so that the whole body can be relaxed and stretched, so that the body can develop comprehensively, symmetrically and harmoniously, and the muscle lines can be 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. The training intensity is easily controlled within the aerobic range, so that stiff muscle blocks will not grow and the whole body lines will be smooth and beautiful.
10 to enhance the adaptability to temperature:
There is not much clothing protection when swimming, which has a certain effect on the body to resist the cold, especially in winter swimming.
1 1, add:
Swimming can make children grow taller during their development.
References:
Baidu Encyclopedia: Swimming