5 early signs of slow kidney function

Our kidneys operate as filters in our body, which eliminate blood waste, along with excess water and toxic substances from the body. A decrease in kidney function leads to waste accumulation throughout the body, which produces various health problems. Slow kidney function leads to chronic kidney disease (CKD), which develops gradually. Early detection of these warning signs enables you to get timely treatment. Here are five warning indicators of reduced kidney function...

A kidney issue typically begins with altered urine frequency and production patterns. You might notice:

Frequent urination becomes more pronounced particularly during nighttime hours (nocturia).
Less urine than usual, or difficulty urinating.
The presence of foam or bubbles in urine indicates that proteins are leaking from the kidneys through urine.
Dark-colored urine or urine with blood.
When kidneys become damaged, they lose their ability to filter blood effectively, which results in protein and blood appearing in the urine. Inform your doctor immediately when you notice these signs.

The kidneys' slowing down function leads to inadequate removal of excess fluid from the body. This causes swelling or puffiness, often in the:

Feet and ankles
Hands
Face, especially around the eyes

The kidneys' failure to regulate salt and water in your body, leads to fluid accumulation. The swelling becomes more pronounced when you spend time standing, or during nighttime hours. Untreated swelling can lead to lung fluid accumulation, which results in breathing difficulties.

The kidneys produce erythropoietin (EPO), which is a hormone, which stimulates the creation of red blood cells. Red blood cells transport oxygen throughout our entire body structure. Slowed kidney function results in decreased EPO production, which then leads to anemia because of reduced red blood cell numbers. The reduction of red blood cells causes persistent fatigue together with muscle weakness, and reduced energy levels after minimal physical activity.
This exhaustion reaches such a point, that routine activities become challenging to perform. Fatigue is one of the earliest indicators of slow kidney function in patients.

The failure of kidneys to function properly, results in waste products and minerals including calcium and phosphorus accumulating in the bloodstream. Because of this,

The skin becomes itchy, especially at night.
The legs experience muscle cramps that transform into spasms.

The accumulation of toxins alongside mineral concentration fluctuations is said to cause irritation in both skin tissues and muscle cells.

A slowing down kidney function, allows toxins to remain in the bloodstream longer, which produces negative effects on brain function. This can cause:

Problems concentrating or paying attention.
Forgetfulness or memory issues.
Feeling confused or having difficulty making decisions.

A person experiencing this symptom, usually describes brain function as being clouded, while also experiencing exhaustion. The brain experiences the same waste accumulation that affects other parts of the body as well, thus indicating the presence of this symptom.


Sources

NHS.uk, "Chronic kidney disease - Symptoms" (2024)
Kidney Care UK, "10 Signs You May Have Kidney Disease"
Mayo Clinic, "Chronic kidney disease - Symptoms and causes"
Kidney.org, "10 Signs You May Have Kidney Disease"
Cleveland Clinic, "Kidney Failure: Stages, Causes, Symptoms" (2025)

Disclaimer: This article is for informational purposes only and is not a substitute for medical advice.

Take care of your kidneys for optimum health

If you notice these signs, consult a doctor.

Hydration is important to keep your kidneys healthy

Take care of your kidneys by following these

Consume a healthy diet to keep your kidneys in a good shape. Eat whole grains, vegetables, and fruits.

Prevention is always better than cure

Take care of your kidneys and stay safe