Sports, bloody sports
I. Basic principles
Generally speaking, people's demand for liquid is about 50ml/kg. If someone's demand is 2400ml, then about 800ml comes from diet, about 1300ml comes from drinks, and about 300ml comes from metabolism. The main consumption modes are: urine about 1400ml, skin about 500ml, breath about 400ml, feces about 100ml.
The main ways of liquid input and output are drinking water and urinating. When the water loss reaches 2% of the body, the work efficiency is obviously reduced. When the water loss reaches 1 L, people will feel thirsty. Under load, people need more water to sweat, metabolize and maintain the balance of cellular system. General 1L liquid is discharged as sweat under load. When the temperature is higher than 20℃, perspiration will increase to 1.5L, and the situation of urine also reflects people's demand for liquid. Under normal circumstances, people urinate 5-6 times a day, and the urine color is yellow. When the urine volume decreases, the color of urine becomes darker, which may be caused by lack of water. It is necessary to supplement enough water.
Two. Domestic research
(1) Before exercise
Generally, 300-500ml of water should be added before 30-12min exercise, which is helpful to slow down the temperature rise, improve the water storage in the body, reduce the degree of water shortage during exercise and prevent dehydration during exercise. Extra 250-500ml of water should be added in extremely hot weather. Pay attention to the amount of water supplement at this stage, because a lot of water stored in the stomach will make people feel uncomfortable and greatly reduce their exercise ability.
(2) In motion
During exercise, water can be supplemented every 2O-3Omin, about 15O-200ml each time. It should be noted that during exercise, you should pay attention to drinking less water. A large amount of water entering the blood will increase the burden on the heart and be harmful to the body. Moreover, drinking too much, drinking too much, makes a lot of salt loss, destroys the balance of salt in the blood, easily increases the fatigue of the body and causes muscle spasms. If you take part in the fitness exercise for about one and a half hours, you need to replenish 15O-300ml of water in stages during the exercise. You can drink water during each break between groups, and the water consumption should not exceed 100ml each time. If the exercise lasts for 2-3 hours, it is best to supplement sugar in time to avoid hypoglycemia, so choose some sweet drinks, such as water mixed juice; If the exercise time exceeds 3 hours, you need to take in about 500ml of water in stages during the exercise and prepare some fruits. Of course, for different intensity of exercise, the amount of hydration should also be adjusted in time. For example, in high-temperature yoga, the water in the body evaporates very quickly at high temperature, so you must bring enough water 1000-2000ml into Bikram yoga room to avoid dehydration.
Take the marathon as an example. Athletes need to drink a glass of water every 6-8 minutes or every kilometer in order to completely replenish the water lost by sweating. However, for most people, this is almost impossible, because exercise suppresses the feeling of thirst. If athletes only rely on thirst to replenish water, the blood flow will decrease by 8%- 10%, which will affect their sports performance. Therefore, it is necessary to make up water in a planned way.
(3) After exercise
Correcting dehydration and supplementing energy in time after strenuous exercise can accelerate functional recovery. The effective recovery of body fluid loss during exercise should include two parts: the total amount of liquid and electrolyte. When the rehydration volume is greater than the sweating volume, if the sweating volume is lost when the rehydration volume is 150%, the body fluid can quickly reach balance. The sodium content in rehydration will also affect the requirement of rehydration. When the sodium concentration is high, the urine volume will be reduced, because sodium ions can capture water in the body, thus contributing to the recovery of body fluids and reducing fluid replacement. However, too high sodium concentration will affect the taste and reduce the intake of liquid.
The total amount of rehydration can be estimated by weight recovery, and rehydration is still based on the principle of small amount and multiple times, and drinking too much is not allowed. Drinking plenty of water at a time only temporarily inhibits thirst, but it will increase urination and sweating, further lose electrolytes in the body, increase the burden on the heart and kidneys, dilute gastric juice and prolong recovery time. The best way to recover body fluids after exercise is to drink sugary electrolyte drinks. The sugar content of the beverage can be 5%- 10%, and the sodium salt content can be 30-40 mg equivalent to obtain rapid rehydration. Don't use salt tablets to supplement sodium. Salt tablets will stimulate the gastrointestinal tract, aggravate dehydration and cause diarrhea.
Third, the composition of rehydration.
For what kind of liquid should be added during exercise, predecessors have done a lot of research, and some have obtained the knowledge of * * * *, for example, the liquid should contain electrolytes and energy substances. Other domestic scholars have also combined rehydration with TCM research and achieved gratifying results. For example, Li Xianghua and others found that the supplement of kiwifruit juice beverage has a good regulatory effect on the immune function of the body during high-intensity exercise, which may be mainly the result of the joint action of high content of vitamin C, actinidine and trace elements zinc and selenium; Wu Jirao and others found that taking compound termite preparation can obviously improve the activity of SOD enzyme in plasma, thus inhibiting the production of free radicals in the body during exercise. At the same time, it is concluded that taking compound termite preparation can effectively delay the occurrence of exercise fatigue and accelerate the recovery of some physiological and biochemical indexes of the body after exercise, thus having obvious anti-exercise fatigue effect; Liao et al.' s research results show that track and field athletes can enhance their physical working ability and accelerate the elimination of sports fatigue by taking royal jelly for promoting blood circulation during training.
Therefore, sports drinks have become the first choice for sports rehydration. Sports drinks refer to drinks containing electrolyte components such as potassium, sodium, calcium and magnesium, and a small amount of sugar and vitamins. This is a drink specially designed for athletes. Exercise helps to restore the balance of water in the body. During strenuous exercise, a certain concentration of sugar in the beverage can provide some fast energy-supplying substances for exercise. Take part in sports with a large amount of exercise and a long time, and you can drink sports drinks. For patients with heart disease and hypertension, the sodium contained in sports drinks will increase the burden on the body, resulting in increased heart load and elevated blood pressure. It is not advisable to drink more sports drinks containing more sodium and salt. In addition, sports drinks contain a certain amount of sugar, which is not suitable for people who exercise and lose weight.
References:
[1] General textbooks for physical education colleges. Sports training [M]. People's Sports Publishing House. 2000.
[2] physique and nutrition recovery [M]. Beijing Sport University Press.2010.7.
[3] Wang Peng. Exercise rehydration [J]. Time sports. 2009 (8): 47。