The kidneys and the blood circulation system depend on each other to stay in good health. The kidneys need a lot of blood vessels to carry out their role in filtering waste from the blood. If blood pressure is high, it can affect kidney function.

Hypertension, or high blood pressure, is one of the most common causes of kidney failure in the United States.

Hypertension can cause the arteries around the kidneys to become narrow, weak, or hard. This affects the blood supply to the kidneys and may mean they receive less oxygen and nutrients. Damaged kidney arteries can keep the kidney’s filtering units, or nephrons, from functioning properly.

Also, kidney damage can raise a person’s blood pressure due to fluid buildup or by producing hormones that further increase blood pressure.

Keep reading to learn more about the link between hypertension and kidney disease.

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Hypertension affects 47% of adults, or 116 million people, in the U.S. This includes people with blood pressure greater than 130/80 millimeters of mercury (mmHg) or taking blood pressure medication. Most adults with hypertension in the U.S., or about 92.1 million people, are not in control of the condition.

The Centers for Disease Control and Prevention (CDC) reports that chronic kidney disease affects more than one in seven, or 37 million, U.S. adults. However, it states that 90% of adults with chronic kidney disease do not know they have it.

Blood pressure is the force with which flowing blood presses on the walls of the arteries as it travels from the heart to all of the body’s tissues and organs.

It is normal for blood pressure to fluctuate throughout the day. However, if blood pressure consistently remains high, it can have serious health consequences. High blood pressure is also known as hypertension.

The American College of Cardiology and the American Heart Association consider blood pressure high at pressures of at least 130/80 mmHg. They define this as stage 1 hypertension. High blood pressure reaches stage 2 at pressures of 140/90 mmHg or above.

Learn more about high blood pressure.

How does high blood pressure affect the body?

According to the CDC, people with hypertension may be at greater risk of heart disease or stroke, two leading causes of death in the U.S.

Many people do not know they have hypertension as the condition does not always cause obvious symptoms. However, a few related health conditions or physical states link to high blood pressure, including:

Hypertension might not be obvious until it causes other health problems. For example, it damages the arteries and makes them less stretchy, which can decrease blood and oxygen flow to the heart. This can lead to:

Hypertension may also affect the brain, causing a stroke if arteries supplying the brain become blocked or burst. Additionally, research has linked cognitive decline and dementia to hypertension.

People with hypertension are at higher risk of developing kidney disease. However, multiple factors play into the development of kidney disease. Hypertension is just one of these.

The kidneys are two small organs that act as the body’s filtration system. They play an important role in controlling blood pressure, alongside a range of other tasks that keep the body in good health.

These include:

  • removing toxins and waste
  • removing excess water and forming urine
  • stimulating red blood cell production
  • maintaining bone health
  • regulating blood chemicals

Learn more about the kidneys.

In people with hypertension, the increased pressure from their blood flow leads to the narrowing of the blood vessels throughout the body. This damages the blood vessels, making it difficult for the kidneys to perform their regulatory function.

Filtering units within the kidney called nephrons do not receive enough oxygen or nutrients to function. As a result, the kidneys cannot effectively remove all the toxins, waste, and extra fluid in the urine.

Excess fluid and waste that builds up in the blood vessels can increase blood pressure further, creating a cycle.

As damage to the blood vessels in the kidneys progresses, it can lead to kidney disease and, ultimately, kidney failure.

Healthy kidneys also respond to a hormone, aldosterone, which helps regulate blood pressure. If the kidneys are unable to function well, it can cause a further elevation in blood pressure and make it difficult for the body to get high blood pressure under control.

Is it possible to reverse kidney damage?

Doctors may use blood and urine tests to detect if a person’s kidney is not functioning properly.

According to the CDC, reversing kidney damage might not be possible, but people can take certain measures to slow it down.

Whether or not the initial cause of kidney disease was hypertension, increased blood pressure in the vessels of the kidneys will worsen the condition. Therefore, it is important for people with kidney disease to find ways to manage their blood pressure successfully.

Learn more about chronic kidney disease.

Symptoms of kidney disease

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), people in the early stages of kidney disease may experience swelling in the legs, feet, ankles, or, in some cases, the hands or face.

Advanced kidney disease symptoms may include:

Learn more about other causes of kidney disease.

People with hypertension can use certain methods to help keep their blood pressure under control. This might require using a combination of medication and making some lifestyle changes.

A person may:

  • Take any medication their doctor prescribes: These might include angiotensin converting enzyme inhibitors and angiotensin receptor blockers, medications to lower blood pressure that may also help slow kidney disease progression.
  • Exercise regularly: It may help to cycle, swim, walk briskly, or wheel in a wheelchair for at least 2.5 hours per week.
  • Maintain a moderate weight: According to the NIDDK, it may be beneficial for people who are overweight or have obesity to reduce their weight by 7–10% during the first year of treatment for high blood pressure. It suggests this can lower the chance of developing health problems related to the condition.
  • Keep stress under control, where possible: Techniques that may help with managing stress include exercising, doing yoga, practicing tai chi, listening to music, or meditating.
  • Limit their salt intake: A 2018 study found that limiting salt consumption could help prevent the progression of kidney damage.
  • Avoid or quit smoking, where applicable: Smoking damages the blood vessels, increases the risk of developing high blood pressure, and can worsen any existing health problems.

Visit our hypertension hub for science-backed resources on managing high blood pressure.

Consistent high blood pressure damages the blood vessels, including those in the kidneys. This places people with hypertension at a higher risk of developing kidney disease. People with either of these conditions may not notice any symptoms in their early stages.

Multiple factors play into kidney disease. While hypertension is a risk factor, the vascular damage it can cause is not the only process that creates kidney disease.

However, even if hypertension is not the original cause of kidney disease, it can worsen the condition. While it is not possible to reverse kidney damage, it may be possible to slow down the progression of the disease using medications and lifestyle interventions.