What Your Kidneys Do (And Why You Can’t Live Without Them)

Kidney disease affects millions of Americans — and most don’t even know they have it. According to the National Kidney Foundation, 1 in 7 adults in the United States has chronic kidney disease (CKD), and many are undiagnosed because early kidney damage rarely causes noticeable symptoms.

That’s why Kidney Awareness Month matters. Before we can prevent kidney disease, slow its progression, or support those living with it, we need to understand one critical question:

What exactly do your kidneys do — and why are they so essential to life?

Where Are Your Kidneys and How Do They Work?
You have two kidneys, each about the size of a fist, located just below your rib cage on either side of your spine. Though small, they are extraordinarily sophisticated organs.

Inside each kidney are about one million microscopic filtering units called nephrons. These nephrons act like highly specialized filtration systems. Every minute, blood flows into the kidneys, waste is separated, and clean blood is returned to circulation.

In fact, your kidneys filter approximately 50 gallons of blood every single day.

But filtration is only part of the story.

The 5 Essential Functions of Your Kidneys
1. Waste Removal:
Your Body’s Natural Filtration System. As your body uses food for energy and cells perform daily metabolic functions, waste products accumulate in your bloodstream. Two major waste markers measured in lab tests are:

• Creatinine (from muscle metabolism)
• Urea (from protein breakdown)

​​​Healthy kidneys remove these substances efficiently through urine. When kidney function declines, these waste products build up in the blood — leading to fatigue, nausea, confusion, and, in severe cases, life-threatening complications.

2. Fluid Balance:
Maintaining the Right Internal Environment. Your body depends on precise fluid regulation. Too much fluid can cause:

• Swelling (edema)
• High blood pressure
• Shortness of breath
• Strain on the heart
  
  

Too little fluid can lead to dehydration, dizziness, and organ stress.
The kidneys constantly adjust urine output to maintain equilibrium. This delicate balance keeps your cardiovascular system stable and your tissues functioning properly.

3. Electrolyte Regulation:
Controlling Sodium, Potassium & More.  Electrolytes are minerals that carry electrical charges. They are essential for:

• Heart rhythm
• Muscle contraction
• Nerve signaling
  

The kidneys tightly regulate:

• Sodium
• Potassium
• Calcium
• Phosphorus
• Magnesium
  
  

When kidneys fail to regulate potassium, levels can rise dangerously — potentially causing fatal heart arrhythmias. This is one reason kidney disease must be taken seriously, even in early stages.

4. Blood Pressure Control:
The Renin-Angiotensin-Aldosterone System (RAAS)Kidneys play a major role in blood pressure regulation through a hormone cascade called the Renin-Angiotensin-Aldosterone System (RAAS).

When blood pressure drops, kidneys release renin, triggering a hormonal chain reaction that:

• Constricts blood vessels
• Retains sodium and fluid
• Raises blood pressure
  

However, when kidneys are damaged, this system can become overactive — contributing to chronic hypertension.

High blood pressure both causes and worsens kidney disease, creating a dangerous cycle.

5. Red Blood Cell Production: Preventing Anemia. 
Kidneys produce a hormone called erythropoietin (EPO). EPO signals bone marrow to produce red blood cells.
When kidney function declines, EPO production drops, leading to anemia. Symptoms may include:

• Fatigue
• Weakness
• Pale skin
• Shortness of breath

This is why anemia is a common complication of chronic kidney disease.

What Is Chronic Kidney Disease (CKD)?
Chronic kidney disease is defined as:

• Kidney damage OR
• An estimated glomerular filtration rate (eGFR) less than 60
• Present for three months or longer
  
  

The eGFR is a blood test that estimates how well your kidneys are filtering. A normal eGFR is typically above 90, though this varies slightly based on age and other factors.
CKD is staged from 1 to 5:

• Stage 1–2: Mild damage, often no symptoms
• Stage 3: Moderate decline
• Stage 4: Severe decline
• Stage 5: Kidney failure (also called End-Stage Renal Disease or ESRD)

The critical point: Kidney disease often progresses silently.

Why Kidney Disease Is Called a “Silent Disease”

Early kidney damage rarely causes pain.  Many people feel completely normal until kidney function has declined significantly. Symptoms such as swelling, fatigue, or appetite changes typically appear in later stages.
This is why screening is essential — especially for individuals at higher risk.

Who Should Be Screened?
You should talk to your healthcare provider about kidney screening if you have:

• Diabetes
• High blood pressure
• Heart disease
• A family history of kidney disease
• Obesity
• Age over 60
  
  

Screening typically includes:

• Serum creatinine (for eGFR calculation)
• Urine albumin-to-creatinine ratio (UACR)
  
  

These simple tests can detect kidney disease early — when intervention is most effective.

What Happens When Kidneys Fail?
When kidney function declines to Stage 5 (kidney failure), the body can no longer maintain safe levels of waste, fluid, and electrolytes.

At that point, treatment options include:

• Dialysis (hemodialysis or peritoneal dialysis)
• Kidney transplantation
  
  

Dialysis replaces part of the kidney’s filtering function, but it cannot fully replicate all of the kidney’s hormonal and regulatory roles. This is why prevention and early management are so important.

Can Kidney Disease Be Prevented?
In many cases — yes.
While not all kidney disease is preventable, progression can often be slowed significantly through:

• Tight blood pressure control
• Blood sugar management (for diabetics)
• Low-sodium diet
• Avoiding NSAID overuse
• Maintaining a healthy weight
• Staying hydrated appropriately
• Regular monitoring of labs
  
  

Early intervention dramatically changes outcomes.

Why Awareness Matters
Kidney disease does not always receive the public attention of other chronic illnesses, yet it impacts millions of families every year.

Organizations like the National Kidney Foundation provide:

• Patient education resources
• Screening programs
• Advocacy for kidney health policy
• Research funding
• Community events like the annual Kidney Walk
  
  

These initiatives save lives through education and early detection.

Our Commitment to Kidney Health
As a dialysis and kidney care team, we see firsthand:

• The strength of patients managing chronic kidney disease
• The importance of early education
• The power of community support
  
  

Kidney Awareness Month is more than a calendar event. It is an opportunity to:

• Encourage screenings
• Support prevention
• Celebrate resilience
• Raise funds to expand education and advocacy efforts
  
  

Every conversation about kidney health matters.

The Bottom Line
Your kidneys are responsible for:

• Filtering waste
• Balancing fluids
• Regulating electrolytes
• Controlling blood pressure
• Producing red blood cells

You cannot live without them.
The most powerful step you can take today is simple:
Know your numbers. Get screened. Share this information.

Awareness leads to prevention.
Prevention leads to better outcomes.
And together, we can change the trajectory of kidney disease in our community.

If you’d like to support kidney education, research, and patient advocacy, consider joining or donating to our upcoming Kidney Walk benefiting the National Kidney Foundation. 

Because kidney health is life health.