"Old Zhang, why have you been drinking so much water lately, yet hardly going to the bathroom?"

"I'm also puzzled. I used to drink a lot and urinate frequently, but now the more I drink, the more swollen I become, and I keep waking up at night."

On a park bench in the morning, two elderly friends were chatting.

Lao Zhang, 62 years old, has been cheerful and optimistic since retiring, and he insists on drinking 2000ml of water every day. However, over the past two months, he has noticed that while he used to feel the urge to urinate as soon as he drank water, now no matter how much he drinks, his urine output has significantly decreased. He also constantly feels swelling in his hands and feet, and his weight has increased by three to four pounds.

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His family initially thought it was just a normal part of aging, but he secretly started looking up health information and grew increasingly anxious. Could it be a kidney problem? Do you also believe that drinking more water is nothing but beneficial for the body?

But in fact, the simple daily act of "drinking water" may hide a significant "health alarm"—especially concerning kidney function! Some bodily signals are not about how much you know or how much you drink, but rather about how keenly you notice subtle changes. What exactly do the four abnormalities after drinking water mean? Many people only realize after reading this: it turns out the kidneys can quietly "sound the alarm"!

Drinking a lot of water but always feeling abnormal? The kidneys really do "speak up" first!

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The kidneys, known as the body’s "detoxification factory," are responsible for filtering blood, regulating water and electrolytes, and expelling waste from the body. Under normal conditions, the kidneys can flexibly adjust urine concentration and output—drinking more water leads to more excretion, exercising more leads to more excretion—maintaining internal balance.

However, once kidney failure occurs (classified into acute and chronic types), this ability to regulate water significantly declines. Whether it’s a malfunction in blood filtration (glomeruli) or water reabsorption (renal tubules), the body’s response after drinking water can become abnormal, even serving as one of the earliest signs of impaired kidney function. According to data from the Chinese Society of Nephrology, the detection rate of chronic kidney disease among Chinese adults is as high as 10.8%, yet most people remain completely unaware in the early stages!

Doctors warn: Kidney issues aren't just about frequent or infrequent urination. Be especially alert to four prominent abnormalities after drinking water, particularly what you might consider "normal increased water intake," which may not actually be safe.

These 4 Abnormalities Are Most Common After Drinking Water When Kidney Function Declines

Abnormal urine output—drinking more water but urinating too little or too much

Healthy individuals urinate more when they drink more and less when they drink less, but in kidney failure, urine output regulation becomes disordered. Some people may drink a lot but produce very little urine or even none at all, while still feeling constantly thirsty, leading to the accumulation of water and toxins in the body. Others may experience a "polyuric phase," where they urinate continuously as soon as they drink water, needing to get up 3–5 times at night due to renal tubule dysfunction and impaired water reabsorption.

According to the *Chinese Kidney Health Guidelines*, individuals with renal dysfunction may have a 24-hour urine output below 400 ml (oliguria) or above 3000 ml (polyuria), both of which are abnormal signs.

Swelling worsens, water goes down, but the person turns into a "bubble."

Do you notice significant swelling in your eyelids, face, or ankles after drinking water? This isn't just "getting fat" from drinking too much water! When kidney function is impaired, water and sodium cannot be excreted, leading to excess fluid accumulation in the tissues.

Studies have shown that patients with kidney failure can gain up to 2 kg in 1–3 days compared to healthy controls. Common signs of edema include "puffy eyelids" upon waking in the morning and shoes feeling tight. If edema is accompanied by reduced urine output, be especially alert to these "signals of kidney failure"!

Nausea and vomiting—not from eating something bad, but from "toxins" causing trouble.

Many people suddenly feel nauseous, experience stomach discomfort, or even vomit occasionally after drinking water, wondering why their stomach issues never seem to improve. In fact, this is a sign that metabolic waste products, such as urea nitrogen and other toxins, are not being excreted due to kidney failure, irritating the gastrointestinal mucosa.

According to a review survey on renal failure in the Chinese Journal of Medicine, approximately 32% of patients with chronic renal failure exhibit significant gastrointestinal symptoms during the progression stage (such as vomiting, decreased appetite, oral odor, etc.). If you consistently feel nauseous after drinking water, especially when eating less but still feeling thirsty, this is not a minor issue!

Blood pressure fluctuations, abnormal blood pressure elevation after drinking water

The kidneys are the body's "blood pressure regulation station." When renal function is impaired and water-sodium retention occurs, drinking water can directly increase blood volume, leading to elevated blood pressure, dizziness, and palpitations. Clinically, about 15-25% of newly diagnosed or refractory hypertension cases are related to kidney disease.

Some patients may notice a sudden spike in blood pressure after drinking water (e.g., from 135/85 mmHg to 150/100 mmHg), accompanied by headaches and other discomfort. This water-related fluctuation in blood pressure often indicates impaired kidney function, and it cannot be resolved simply by "drinking less water"!

Does any abnormality necessarily mean kidney dysfunction? Not necessarily. Excessive daily water intake, intense sweating, or a diet high in salt can also affect urine output and cause swelling. However, if the aforementioned four abnormalities persist long-term without other causes such as fever, excessive fluid loss, or heart disease, kidney issues should be highly suspected. It is essential to seek medical attention promptly and undergo urine and kidney function tests.

How to protect kidney health? Doctors recommend these practical daily actions

Maintain moderate water intake. Drinking more water does not necessarily equate to better health. For the average adult, limiting daily intake to around 1500-2000 ml is sufficient. Individuals with known chronic conditions or the elderly should follow their doctor's advice, drinking water in small, frequent amounts rather than consuming large quantities at once.

Control salt intake. A high-salt diet increases the burden on the kidneys and exacerbates water and sodium retention. Authoritative guidelines recommend limiting daily salt intake to less than 6 grams (approximately the amount that fits in a beer bottle cap).

Avoid misuse of medications. Some commonly used painkillers and antibiotics can directly damage nephrons if taken without medical supervision or in high doses over long periods. For drugs that are not suitable for indiscriminate use, drinking more water will not help eliminate toxins.

Undergo regular health screenings for kidney function. Individuals with a history of diabetes, hypertension, or a family genetic predisposition should undergo comprehensive kidney function tests, including urinalysis, once or twice a year. Indicators such as serum creatinine, blood urea nitrogen, and urinary protein are sensitive markers of early kidney damage, providing an opportunity for timely prevention and treatment.

Engage in reasonable exercise and maintain a healthy weight. Lifestyle factors such as obesity, prolonged sitting, and insomnia can increase the metabolic and endocrine burden on the kidneys. Scientific exercise, a balanced diet, quitting smoking, and limiting alcohol consumption are all effective "kidney-protecting actions." Do not wait until a doctor advises you to "pay attention to your water intake" before regretting your choices!