Which is worse: wanting to urinate as soon as you drink water or drinking a lot of water but not urinating?

Tuchong Creative

Have you ever had this experience: you feel like urinating as soon as you drink water? In contrast, some people drink more water than you, but rarely go to the toilet. Why does this happen? Which of these two situations is better?

Before answering this question, we must first understand why we need to drink water?

Because drinking water is essential to maintaining good health. 70% of our body weight is water, especially more than 90% of plasma is water. The existence of so much water is necessary. First, it can play a role similar to water transport in plasma, transporting nutrients to cells and taking away metabolic waste. Second, it has the function of maintaining osmotic pressure. Junior high school biology taught that if the osmotic pressure inside and outside the cell is different, the normal morphology of the cell will be destroyed. Third, water is also the basis of metabolism. All biochemical reactions in cells, such as the tricarboxylic acid cycle, gluconeogenesis, and glycolysis, must be completed in a water environment. Therefore, it is not wrong to say that water is the source of life.

In addition, the body excretes waste water in the form of urine every day, and also secretes digestive juices, saliva, and tears. When the ambient temperature is high or when exercising, we also sweat, which are all water. Since there is loss, it must be replenished quickly, otherwise once the water in the body is reduced, dehydration will occur. It can be said that people can go a day without eating, but they cannot go without drinking water. If the lack of water is serious, it can be fatal.

The second is the urine problem. The main reason for the confusion is that you are worried about your body. If you want to know the answer, you must first understand a process, that is, how the water you drink turns into urine.

It is certain that water does not turn into urine immediately after drinking it, it will go around in the body for a long time. Let's briefly describe it, after drinking water, the first to feel the moisture are the mouth and throat, but the real water absorption starts from the stomach, and most of the water is actually absorbed in the small intestine mucosa.

Where does the absorbed water go? The answer is that it enters the blood and becomes part of the plasma, and then circulates throughout the body. When the body senses that new water has entered, it will excrete part of the water originally in the blood. When this part of water flows through the kidneys, it will first form primary urine under the action of the glomerulus, which is the initial state of urine. Then, it will be repeatedly reabsorbed by the renal tubules and finally form urine, which flows into the bladder along the ureter for storage. The whole process from drinking water to urine formation generally takes 40 minutes.

Why does urine have different shades of color? What's the reason? And what does the amount of urine have to do with it?

Normal urine is slightly yellow because it contains bilirubin metabolites. Normal urine is light yellow. If you don't drink enough water, the urine will be concentrated and the color will turn yellow or even dark yellow. On the contrary, if you drink too much water, the color will be lighter. If you have certain diseases, such as nephritis, urinary tract infection, or eat too much food containing pigments, such as carrots and pumpkins, the color of urine will be darker. As for the amount of urine, it is related to the amount of water you drink. For healthy people, the more water you drink, the more urine you will naturally produce. If you drink very little water, you may even have less urine.

Why do some people feel the urge to go to the toilet after drinking water, while others don’t?

Generally speaking, as long as you drink enough water, you will naturally produce more urine. And the faster you drink water, the faster urine is formed. Especially after eating some diuretic foods such as watermelon, urine is formed even faster.

However, drinking water is not the same as urinating, because there is a urine storage tank in our body, which is the bladder. Generally speaking, when the urine in the bladder reaches about 300 ml, you will feel the urge to urinate. At this time, the brain will receive a signal from the bladder saying that the bladder is full and will overflow if you don't empty it out. The brain will prompt you to find a place to "drain" and relieve the pressure on the bladder. However, if you don't find a suitable place, the bladder and urethral sphincter will remain tense and resist to the end.

However, everyone's physique is different. Even if they drink the same amount of water, some people urinate more and some people urinate less. This is because people of different genders and weights have different amounts of circulating blood, so the amount of water that needs to be added to the plasma is naturally different, and the excess water will be excreted. Urine volume is also related to sweating. When drinking the same amount of water, the more people sweat, the less they urinate. In addition, urine volume will also change in certain disease states, such as metabolic diseases such as diabetes and hyperthyroidism, and people with kidney disease will also have increased urine volume.

Some people have a very elastic bladder and a stronger tolerance, and can even drink beer from a box without any problem, but this is not a good habit, and is very detrimental to the health of the circulation and urinary system, and may even cause urinary tract infection or nephritis. Some people have a slightly poorer tolerance and want to go to the toilet as soon as they feel the urge to urinate, while some people are purely a matter of habit, such as the act of drinking water gives the brain a signal to release water.

How much water should we drink for our health, and how do we know when we need to drink water?

According to the recommendations of the Chinese Dietary Guidelines, adult men with low physical activity levels in a mild climate should drink at least 1,700 ml of water a day, and women should drink 1,500 ml of water. If the weather is hot or if you have done a lot of physical activity, you should drink more water. The correct way to drink water is not to wait until you are thirsty due to dehydration, but to drink 100-200 ml of water every 1-2 hours. Remember to drink water after exercise or when you wake up. When you are thirsty or urinate less, it means that your body is already dehydrated. If you get used to drinking water at this time, it will affect your body over time.

To sum up, you should develop the habit of drinking water regularly, do not hold your urine and do not urinate too frequently. 5-7 times is normal.

This article is a work supported by the Science Popularization China Creation Cultivation Program

Author: Zhang Yu, PhD in Nutrition

Reviewer: Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.