How Does Kidney Disease Affect Heart Health?

The kidneys and the heart are closely connected. Although they perform different jobs, they rely on each other to keep the body healthy. The kidneys filter waste, remove extra fluid, and help control blood pressure, while the heart pumps blood around the body so the kidneys can do their work.

When the kidneys become damaged, the heart often has to work harder. Likewise, when the heart is not working properly, the kidneys may not receive enough blood to function well. This means that disease affecting one organ can also damage the other.

"People with chronic kidney disease (CKD) have a much higher risk of developing heart disease than those with healthy kidneys. In fact, heart disease is one of the leading causes of illness and death in people with kidney disease. Understanding this link can help people take steps to protect both organs," shares Dr Deebanshu Gupta, Cardiologist at Sarvodya Hospital, Jalandhar.

The Connection Between Kidneys and Heart

The heart and kidneys work together every minute of the day.

The heart pumps blood to the kidneys, providing them with oxygen and nutrients. The kidneys then clean the blood by removing waste and excess fluid before returning it to the circulation. They also help regulate blood pressure, balance minerals such as sodium and potassium, and produce hormones that support healthy blood cells.

When the kidneys stop working properly, these important functions are affected. This places extra pressure on the heart. Similarly, if the heart cannot pump enough blood, the kidneys receive less oxygen-rich blood, which can reduce their ability to work effectively.

According to a study published in the Journal of CardioRenal Medicine, this two-way relationship is known as the cardiorenal connection.

High Blood Pressure: Link Between Kidney Disease and Heart Disease

High blood pressure is one of the strongest connections between kidney disease and heart disease.

Healthy kidneys help control blood pressure by regulating the amount of fluid and salt in the body. Damaged kidneys lose this ability, allowing excess fluid and sodium to build up in the bloodstream.

As blood pressure rises, the heart has to pump harder to move blood around the body. Over time, this extra workload can enlarge the heart muscle and damage blood vessels.

High blood pressure can also worsen kidney damage, creating a cycle in which kidney disease and heart disease continue to affect each other.

Keeping blood pressure under control is one of the most important ways to protect both organs.

Fluid Build-up Puts Pressure on the Heart

Another problem caused by kidney disease is fluid retention.

Healthy kidneys remove excess water from the body. When kidney function declines, this fluid begins to build up. Swelling may appear in the feet, ankles, legs or hands. In severe cases, fluid can collect in the lungs, making breathing difficult.

The extra fluid increases the amount of blood the heart must pump. This forces the heart to work harder and may eventually lead to heart failure, where the heart cannot pump enough blood to meet the body's needs, according to the Kidney Research UK.

People with both kidney disease and heart failure often experience tiredness, breathlessness and swelling that becomes worse over time.

Also Read: Silent Heart Attack: Symptoms, Causes, Risk Factors, Diagnosis and Treatment

Kidney Disease Can Damage Blood Vessels

Kidney disease also affects the blood vessels.

According to a study published in the journal ‘Biomolecules’, people with chronic kidney disease are more likely to develop atherosclerosis, a condition in which fatty deposits build up inside the arteries. This narrows the blood vessels and reduces blood flow to the heart and brain.

Kidney disease is also linked with long-term inflammation and changes in the balance of calcium and phosphate in the blood. These changes can make arteries become stiff and less flexible.

Damaged arteries increase the risk of heart attacks, strokes and poor circulation.

Anaemia Increases the Heart's Workload

The kidneys produce a hormone called erythropoietin, which tells the bone marrow to make red blood cells.

When the kidneys are damaged, they produce less of this hormone. As a result, fewer red blood cells are made, leading to anaemia.

With fewer red blood cells carrying oxygen around the body, the heart has to pump faster to meet the body's needs.

Over time, this extra effort can enlarge the heart and increase the risk of heart failure, especially if anaemia is not treated.

Shared Risk Factors

Kidney disease and heart disease often occur together because they share many of the same risk factors including:

• Diabetes
• High blood pressure
• High cholesterol
• Smoking
• Obesity
• Lack of physical activity
• Older age
• A family history of kidney or heart disease

Managing these risk factors reduces the chance of developing both conditions.

Signs to Watch For

Kidney disease often develops slowly, and symptoms may not appear until significant damage has already occurred. Possible signs include:

• Swollen feet, ankles or hands
• Tiredness
• Loss of appetite
• Changes in urination
• Difficulty concentrating
• Nausea
• Itchy skin
• Heart problems may cause chest pain, shortness of breath, dizziness, palpitations or swelling in the legs.

Anyone with these symptoms, particularly those with diabetes or high blood pressure, should seek medical advice.

How to Protect Your Heart and Kidneys

Looking after your kidneys also benefits your heart. Healthy habits include:

• Keeping blood pressure under control
• Managing diabetes effectively
• Eating a balanced diet that is low in salt
• Staying physically active
• Maintaining a healthy weight
• Avoiding smoking
• Limiting alcohol intake
• Taking medicines as prescribed
• Attending regular medical check-ups

People with kidney disease should also have regular blood and urine tests to monitor kidney function and detect any changes early.

Early treatment can slow kidney damage and reduce the risk of heart complications.

Why Early Diagnosis Matters

Many people are diagnosed with chronic kidney disease only after it has progressed because the early stages often have no symptoms.

Routine screening is particularly important for people with diabetes, high blood pressure or a family history of kidney disease. Simple blood and urine tests can detect kidney damage before serious problems develop.

Early diagnosis allows doctors to begin treatment sooner, helping preserve kidney function and reducing the likelihood of heart disease.

Final Word

Kidney disease and heart disease are closely linked. Damaged kidneys can cause high blood pressure, fluid retention, anaemia and blood vessel damage, all of which place extra strain on the heart. At the same time, heart disease can reduce blood flow to the kidneys, making kidney function worse. Because these organs depend on each other, protecting one helps protect the other. Managing blood pressure, controlling diabetes, following a healthy lifestyle, and having regular health checks can lower the risk of complications.