How can patients with kidney disease drink to stay healthy?

How can patients with kidney disease drink to stay healthy?

Author: Chen Zhou Shanghai Changhai Hospital

Reviewer: Mei Xiaobin, Chief Physician, Shanghai Changhai Hospital

We all know that water is the source of life, and there is no life without water. But do you know that how to drink water scientifically is also a science. Drinking too much or too little water will have an impact on our body, especially for patients with renal insufficiency, they should pay more attention to controlling water intake and excretion.

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So, how should kidney patients drink water? To answer this question, let's first understand what water balance is and the "gains and losses" of water in the human body under normal circumstances.

1. What is water balance?

Water balance refers to the balance of water intake and discharge in the human body. We take in and discharge water through different pathways every day to maintain the constant amount of fluid in the human body.

So, where do we take in and excrete water every day?

1. Ways to take in water

1. Drinking water is the most direct and common way to consume water. We can replenish the water needed by the body by drinking boiled water, tea, juice, milk, etc.

2. Water in food This is an invisible way to take in water. When we eat, we also take in the water contained in the food. For example, almost 90% of the weight of fruits and vegetables is water.

3. Water generated by oxidation This is an endogenous way of water intake. We also produce some water during the process of breathing and metabolism.

(II) Ways to discharge water

1. Urine This is the main way of drainage. We can excrete excess or harmful water and other substances from the body through urine. Normally, an adult urinates 500 to 1500 ml per day.

2. Sweat During exercise or in a hot environment, the human body will excrete sweat through the skin to dissipate heat and regulate body temperature. Normally, an adult excretes about 900 ml of sweat through the skin every day.

3. Breathing When we breathe, we exhale some of the water in our lungs. Normally, an adult exhales about 400 ml of water per day.

4. Feces When we defecate, we excrete some of the water in the intestines. Normally, an adult excretes about 200 ml of water through feces every day.

3. Maintaining water balance

Under normal circumstances, the human body system will naturally balance the water in and out, so that the water intake and excretion are roughly equal. For example, when we are dehydrated, the following changes will occur.

1. Increased blood sodium and blood osmotic pressure stimulate the body's thirst center, making us feel thirsty, thus prompting us to drink water.

2. The secretion of antidiuretic hormone (ADH) in the pituitary gland increases, which can act on the kidneys to reduce the excretion of water and thus retain more water.

3. The secretion of aldosterone in the adrenal glands increases, which can act on the kidneys to allow the kidneys to absorb more sodium and water, thereby increasing blood volume.

These changes tend to restore the body's normal water balance.

2. Under normal circumstances, the "gain and loss" of human water

So, under normal circumstances, how much water should we take in and excrete every day? This actually depends on many factors, such as age, gender, weight, climate, activity level, etc. We can make a simple estimate.

A healthy adult excretes about 1600 ml of water every day, including: 500 ml through the skin, 400 ml through the respiratory tract, 200 ml through feces, and 500 ml through urine.

If you want to balance this 1600 ml of water, the human body needs to obtain water through the following ways: 800 ml of water from food, 300 ml of water produced by oxidation, and 500 ml of drinking water.

It can be seen that for normal people, if they want to maintain the most basic life and health, they need to drink at least 500 ml of water every day (this 500 ml is estimated based on the balance between the total amount of water produced by the human body and the minimum rate of excretion through urine). If you cannot eat (fasting), you need to drink at least 1300 ml of water every day. This is also the basis for the recommendation that healthy people drink 1500-2000 ml of water every day.

Of course, these numbers are just a rough range and are not set in stone. In real life, we also need to adjust the amount of water we drink according to our physical condition and environmental factors. For example, when we exercise or sweat a lot, we need to increase the amount of water we drink to replenish the lost water and electrolytes; when we have a fever or vomit or diarrhea, we also need to increase the amount of water we drink.

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3. How do special groups of people drink water?

For some special groups, such as patients with kidney disease, the issue of drinking water is more complicated and important. Because their kidney function is impaired and they cannot normally regulate the balance of water and electrolytes. If they drink too much or too little water, it will have a serious impact on their bodies.

1. For patients with urinary tract infection, kidney stones, etc., it is recommended to actively replenish water, drink more water and urinate frequently. The purpose is to promote the timely excretion of bacteria and small stones through physical flushing of the urethra.

2. For patients with obvious edema, heart failure or anuria, it is necessary to control the amount of water you drink every day. It is recommended to listen to the doctor and not act on your own. The doctor will formulate a reasonable drinking plan based on the patient's urine volume, weight, blood pressure and other indicators. Generally speaking, the amount of water you drink every day should not exceed the urine volume of the previous day plus 500 ml.

3. For patients with hypertension, hyperglycemia, hyperuricemia, etc., they need to replenish water appropriately every day, drink water moderately, and check frequently. The purpose is to reduce the damage to blood vessels and kidneys by diluting sodium, sugar, uric acid and other substances in the blood. Generally speaking, the daily water intake should be 1500-2000 ml. At the same time, blood pressure, blood sugar, uric acid and other indicators should be tested regularly, and medication and diet should be adjusted in time.