We come to the conclusion that it is wrong to drink eight glasses of water a day!

Is there any basis for saying eight glasses of water a day?

Medical research points out that people should consume at least 2000 ml of water every day, which is equivalent to about 8 cups, so there is a saying of "eight glasses of water a day". However, the food that the human body consumes every day already contains a lot of water, which should be decided according to the actual situation of the individual. Don't be superstitious about the saying "eight glasses of water" If you don't drink enough water in a day, then you will drink the rest immediately, which will not only make your stomach feel heavy, affect your normal breathing, but also cause water poisoning. ?

Detailed explanation of eight glasses of water

Books and articles in medical journals claim that the "8×8" drinking principle-eight glasses of water a day and eight ounces (237 ml) each time-can bring many benefits to human health, from accelerating weight loss, eliminating toxins in the body, fighting constipation, fatigue and dry skin, to accelerating the recovery of colds and flu. This statement lacks scientific basis.

The media even joked that the principle of "8×8" drinking water is "watertight" and "cannot be decontaminated".

Let science speak.

The debate about eight glasses of water is more from the perspective of the problem.

Many studies have linked drinking more water with health, but critics usually think that the data of such studies are insufficient, the conclusions are uncertain or not widely applicable. For example:

1999 A study of nearly 48,000 men published in the New England Journal of Medicine 10 showed that the risk of bladder cancer decreased by 7% for every glass of water people drank every day. Other studies have found that the more water you drink, the less likely you are to develop colon polyps with precancerous characteristics. A study of 20,000 Adventists in California, published in the American Journal of Epidemiology, found that women who drink at least five glasses of water a day are 465,438+0% less likely to develop fatal heart disease, and men are 54% less likely than those who drink only two glasses of water a day.

Henry, a physiologist at Dartmouth Medical College? In a groundbreaking article published in the American Journal of Physiology in 2002, Walding discussed the above studies and concluded that these studies could not support the general recommendation that everyone should drink eight glasses of water a day, but only applied to those who were known to have certain diseases. Six years later, Dr. Valding said, I haven't seen any scientific report to refute my conclusion.

Similarly, in an editorial in April, the Journal of the American Society of Nephrology refuted the conclusion of small-scale research that drinking water can increase heat production (burn calories), reduce migraine attacks and accelerate skin blood circulation. The editorial reiterated Dr. Valding's conclusion that there is no clear evidence that drinking more water is good for health. However, the editorial added, we also admit that there is no clear evidence that drinking more water is not good for health.

This makes researchers in this field feel quite frustrated.

What is water poisoning?

Water poisoning is a symptom of dehydration and hyponatremia caused by excessive intake of water. Although the probability of death from water poisoning is very low, it is still possible. The maximum sustained diuresis rate of human kidney is 16 ml per minute. Once the rate of water intake exceeds this standard, the excess water will expand the cells, thus causing dehydration and hyponatremia. When drinking too much water, the electrolyte in the blood drops to a concentration lower than safe water because it is excreted by water, which affects the operation of the brain and may be fatal.

The specific causes of water poisoning are as follows:

Drinking too much water or injecting too much glucose intravenously (such as abusing sodium-free solution during hypotonic dehydration), especially for patients with poor heart and kidney function and infants with poor renal dilution function. In addition, after major surgery, the body is in a state of stress, with excessive secretion of antidiuretic hormone and decreased urine output. At this time, if a large amount of infusion is given, it will also cause water poisoning. Another example is a child with Hirschsprung's disease. After washing the intestine with a large amount of water, a large amount of water is absorbed into the blood circulation from the intestinal wall, leading to water poisoning.

Malnutrition, due to low plasma protein and blood sodium, the osmotic pressure of extracellular fluid is reduced, and water enters intracellular fluid from extracellular fluid, which reduces effective circulation, promotes the secretion of antidiuretic hormone, and reduces urine volume, resulting in water retention.

Pneumonia, severe infection, shock and brain diseases, at this time, the secretion of antidiuretic hormone increases, leading to water storage poisoning.

Acute renal failure and oliguria, even if ingested normally, can cause water poisoning.

Drowned in fresh water.

Mental factors: mental stress, severe pain and various acute stress States (such as major surgery and trauma).

Tumors.

Another possibility is that you drink too much water because of the influence of an unknown schizophrenia drug. The side effect of this drug will affect the secretion of antidiuretic hormone, making patients feel thirsty and keep drinking water.

There is too much water in the body, first of all, the extracellular fluid is too large and in a hypotonic state, and the water is transferred from the outside to the inside of the cell. Therefore, water poisoning is due to the increase of the volume of intracellular and extracellular fluids, but the proportion of body fluids is still normal (that is, intracellular fluid accounts for 2/3, and extracellular fluids account for 1/3). Mild to moderate water poisoning, the water stored in tissue fluid is not enough to cause depressed edema or pulmonary edema, and the clinical manifestations are not obvious and can be ignored, but it can still develop into increased intracranial pressure.

We give advice.

Judging when to replenish water by urine color

Director Ren reminded that drinking water should also be people-oriented. Normal people can judge when to replenish water by the color of urine: normal urine is light yellow, and if it is too dark, it should be replenished.

In addition, drinking water varies from person to person. Patients with acute nephritis and renal failure should not drink more water, and drink more water than usual when they have a cold and fever.

It's healthier to drink water like this.

Drinking warm water instead of cold water will suddenly cool the gastrointestinal mucosa, shrink the originally unobstructed capillaries, and cause gastrointestinal discomfort and even diarrhea. Too hot water enters the esophagus, which is easy to destroy the esophageal mucosa and induce esophageal cancer. Therefore, the optimum temperature of drinking water is 10℃~30℃.

Drink light but not sweet. Drink some light salt water to supplement sodium in hot weather. Self-made mung bean soup and lemonade can not only relieve summer heat, but also supplement vitamins and other nutrients. All kinds of sweet drinks are high in sugar and energy, and their nutrients are monotonous. It is not recommended to drink in large quantities, nor can it be used to replace boiled water.

Drinking slowly but not quickly, drinking a lot of water quickly, will make the blood dilute rapidly, increase the burden on the heart, and it is easy to swallow a lot of air together, which is easy to cause hiccups or bloating. The correct way to drink water is to put a mouthful of water in your mouth and slowly swallow it several times, which can fully moisten your mouth and throat and effectively quench your thirst.

Drink early, not late. When you are thirsty, upset, tired and have a headache, it means that the cells of your body have begun to dehydrate. At this time, drinking water is already "passive drinking". Over time, the human body will be in a state of potential water shortage for a long time, which is not conducive to normal metabolism. Therefore, drinking water, like eating, also needs timing, changing passive drinking into active drinking, and drinking water before feeling "thirsty".

Drinking water also "eats" water. Water in fruits and vegetables such as cucumber, watermelon and tomato can enter cells more easily than ordinary water. Therefore, while drinking water, you should also "eat" water. Fruits and vegetables are also rich in various antioxidants, minerals and important B vitamins, which are of great benefit to enhancing human immunity, preventing aging and resisting diseases.

Reference materials &; Reference link:

Baidu Encyclopedia:/news/m/2013-08-08/155131553.html.

China Waterway Network:/html/culture/2013/08/83008003905284.html.

39 Health Network: /nutrition/087/4/549825.html