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The cold and dryness of winter pose a dual challenge for patients with chronic kidney disease. Low temperatures make it harder to maintain the balance of water and salt, while indoor heating causes the air to become dry, easily leading to thirst and a sore throat. Additionally, a higher salt intake in winter diets inadvertently increases the burden on the kidneys. So, how can one hydrate scientifically in winter? Experts from Kuangjie provide some practical tips to help everyone stay healthy during the cold season.

General Principles for Hydration: Strict Salt Control Personalized Fine-Tuning

When kidney function is impaired, excessive drinking may lead to fluid overload, blood pressure fluctuations, and even hyponatremia, pulmonary edema, heart failure, etc.; while insufficient drinking may trigger constipation, dry mouth and throat, and even hypoperfusion, elevated blood creatinine. So, how much water should one drink?

General principles for drinking water in winter:

1. Strictly limit sodium (≈salt ≤ 5g/d);

2. On this basis, fine-tune by combining urine output, symptoms, and signs.

What to drink: Choose the right beverages

Kidney disease patients should prioritize warm plain water, drink less sparkling water and functional beverages. Tea or coffee can be consumed in small amounts, but they should be accounted for in total liquid intake, and it's best to use less sugar and milk. Coconut water, broths, and juices contain both water and potassium, sugar, and sodium, so chronic kidney disease patients, especially those in advanced stages or on dialysis, should use them with caution.

How much to drink: How to gauge your fluid intake

01 How to determine if you're drinking enough water

First, look at the weight trend (after urinating and defecating in the morning, fasting, weighing the same scale): If it increases continuously in the short term, with a daily increase of ≥0.5-1.0kg, it indicates overhydration;

Second, observe physical signs and breathing. If symptoms such as ankle pitting, worsening edema, elevated blood pressure, chest tightness and shortness of breath, or even labored breathing appear, it indicates overhydration. Severe symptoms require immediate medical attention;

Third, check urine volume and color. If there is a significant decrease and the color is dark, it usually suggests that water intake should be appropriately increased.

02 Water Intake for Patients in Different Stages of Kidney Function

Chronic Kidney Disease Stage 1-2 (Glomerular Filtration Rate ≥ 60 mL/min/1.73m²): If urine output is normal, without edema, and blood pressure is relatively stable, the total daily fluid intake (including plain water + soup/cereal beverages + "hidden water" from fruits and vegetables) is basically the same as that of healthy individuals: about 1500-2000 mL. The premise is to limit salt (no more than 5 grams of salt per day). Once salt intake is controlled, thirst is reduced, making it easier to manage fluid intake.

Chronic Kidney Disease Stage 3-4 (Glomerular Filtration Rate 15-59 mL/min/1.73m²): Refer to the formula: Today's total fluid intake ≈ Yesterday's urine output + 500 mL (if the environment is hot, feverish, or sweating heavily, it can be increased to 600 mL). Then adjust the intake slightly up or down by 200-300 mL daily based on weight trends, ankle edema, and blood pressure.

Chronic Kidney Disease Stage 5 (Glomerular Filtration Rate < 15 mL/min/1.73m²): Some patients experience significantly reduced urine output. The principle is "prioritize stability over quantity," first controlling salt intake, then cautiously planning fluid intake under medical guidance to avoid edema caused by "drinking but not excreting." Adjust diuretics or dialysis plans as needed according to medical advice.

03 Dialysis Patient Fluid Intake

Patients undergoing hemodialysis should aim for a dry weight gain (IDWG) of ≤ 2-3% of dry weight (or ≤ 2-3 kg, whichever is smaller) as a minimum standard; if this limit is frequently exceeded, it is usually due to "salt load + free water" both being excessive, requiring a reduction in dietary sodium and ultrafiltration strategy. Peritoneal dialysis is relatively stable, but the general principle remains unchanged: sodium restriction first, with fine-tuning of fluid intake based on weight, edema, blood pressure, and ultrafiltration volume.

More importantly, whether undergoing hemodialysis or peritoneal dialysis, regular communication with the supervising healthcare team is essential.

How to Drink: Hydration Tips for Kidney Patients

01 Practical Hydration Tips

Record your daily water intake; sip small amounts slowly, avoid gulping; distribute it roughly 3:3:2:2 for morning/noon/evening/night, stop drinking 2-3 hours before bed to help reduce nighttime urination; avoid cold water, prefer warm water; moisturize the indoor air, don’t rush to drink when coming back from outside, wait and see before rehydration.

02 How to calculate "hidden water"

"Hidden water" = the total sum of all water except plain water, including soup, congee, dairy products, beverages, fruits, vegetables, etc. Specifically, a bowl of soup or congee, or a small cup of beverage ≈ 300-400mL of water, fruits like watermelon and oranges can contain up to 85%-90% water. Vegetables like cucumber, tomato, and lettuce also have high water content, about 80-90%, all of which should be included in your daily fluid intake, especially for patients with edema, oliguria, and heart failure, proper management of hidden water is crucial.

03 How to Easily Limit Salt Intake

Limit salt intake, reduce thirst sensation, and it will be easier to control water intake. You can follow these steps to make limiting salt effortless:

1. Set a goal: Limit daily salt intake to about 5 grams (sodium < 2 grams);

2. Gradually reduce: Reduce salt by 20% in the first week, another 20% in the second week, and aim to reach ≤5g/day in the third week;

3. Use measuring spoons and limit total amount—Measure out the day's salt using measuring spoons and a "salt-limiting jar" while cooking, distribute it per meal, and stop once it's used up;

4. Avoid high-salt foods;

5. Smartly use flavor substitutes, such as replacing heavy saltiness with "sour, pungent, savory, and spicy" (lemon/rice vinegar, scallions, ginger, garlic, and a small amount of chili);

6. Provide timely feedback—measure blood pressure and weigh yourself every morning: if thirst decreases, nighttime urination reduces, and blood pressure stabilizes, it means you're on the right track. Additionally, it's important to note that most "low-sodium salt" contains potassium, so caution is needed for late-stage CKD or high-potassium individuals.

If these signs appear, seek medical attention immediately.

1. Obvious edema, sudden weight gain of ≥2kg in a short period, chest tightness and shortness of breath, even orthopnea;

2. Sudden decrease in urine output (<400mL/d) or anuria;

3. Morning blood pressure consistently higher than usual; 4. Rapid rise in creatinine/blood potassium; 5. High fever accompanied by symptoms such as vomiting/diarrhea, indicating high risk of volume or electrolyte imbalance, seek medical attention immediately.