Answer:

Healthy kidneys effectively regulate urine volume according to the body's needs. During the day, as the body is active and consumes fluids, the kidneys excrete excess water. At night, kidneys enhance their ability to concentrate urine, limiting the need to urinate while sleeping.

When kidney function declines or chronic kidney disease progresses, the kidneys' ability to concentrate urine may decrease. The urine becomes more dilute, and the amount of urine produced at night can increase, causing individuals to wake up multiple times to urinate.

In some cases, especially with leg swelling or fluid retention, nighttime urination also relates to changes in body fluid distribution. During the day, when standing or sitting for extended periods, fluid can accumulate in the legs. When lying down to sleep, this fluid returns to the circulatory system, where it is filtered and excreted by the kidneys, increasing nighttime urine output.

However, frequent nighttime urination is not a specific symptom of kidney disease. This condition can also occur in individuals who drink a lot of fluids in the evening, consume alcohol or caffeine, or have prostate conditions, diabetes, heart failure, or certain sleep disorders. Therefore, a doctor needs to evaluate accompanying symptoms and conduct appropriate tests to determine the cause.

Doctor Huy examining and consulting a patient with chronic kidney disease. Photo: Tam Anh General Hospital

Your case requires an assessment of risk factors, the extent of kidney function decline, and other potential causes. A doctor may order tests such as creatinine, estimated glomerular filtration rate (eGFR), urinalysis, and urine albumin, along with checking blood pressure, blood sugar, and reviewing current medications.

You should also record the number of times you urinate, the amount of fluid you drink, and when symptoms appear throughout the day to provide information to your doctor during the examination. If you experience difficulty urinating, a weak urine stream, incomplete bladder emptying, or straining during urination, the doctor may further evaluate your prostate condition.

If the cause of nighttime urination is related to kidney disease, it is essential to manage blood pressure, blood sugar, and co-existing conditions effectively, take prescribed medications, and adjust salt and fluid intake appropriate for your kidney function. You should not arbitrarily restrict fluid intake excessively just because of nighttime urination, as the amount of water needed varies for each person depending on kidney function, urine output, and accompanying medical conditions.

You should seek an early medical examination to identify the cause and establish a treatment plan, including regular monitoring, risk factor control, and lifestyle adjustments to manage the condition effectively and prevent complications.

Dr. Vo Xuan Huy, M.S.

Department of Urology, Center for Urology - Nephrology - Andrology

Tam Anh General Hospital, Ho Chi Minh City