The kidneys play a crucial role in filtering blood, eliminating toxins, and regulating blood pressure. Yet, many people don’t recognize the early warning signs of kidney weakness—especially those that appear at night.

Here are five common nighttime symptoms that may signal kidney trouble.

1. Frequent Nighttime Urination

If you often wake up many times at night to urinate, it may be a sign of underlying kidney problems.

Urinating more than twice per night without an increase in evening fluid intake is among the earliest indicators of weakened kidney function. As per a study published in the Journal of Urology, frequent nighttime urination may be linked to a decline in the kidneys’ ability to concentrate urine. When kidney function weakens, the organs lose control over fluid excretion, causing frequent urination at night. If this persists, patients should undergo blood tests such as creatinine measurement and glomerular filtration rate (GFR) assessment.

2. Swelling in the Feet or Ankles at Night