Can high blood pressure affect kidney function?

When was the last time you thought about your blood pressure? If it’s not high, probably not recently. And what about kidney function? Again, probably not something you’ve thought about. But when you have chronic kidney disease or high blood pressure, you might not realize that each condition can complicate the other. Here’s what to know about the relationship between high blood pressure and how well your kidneys function.

What is high blood pressure?

High blood pressure, or hypertension, is a chronic condition where your numbers measure 130/80 or higher consistently. “The higher the number, the higher the force your blood has on your artery walls,” says Atul Bali, MD, nephrologist at Geisinger. High blood pressure often has no symptoms.  It can have many causes including:

• Eating a diet high in salt
• Being sedentary
• Smoking
• Excessive alcohol consumption
• Diabetes
• Obesity
• Smoking
• Prolonged stress

Another cause of hypertension? Kidney disease. “High blood pressure can also be one of the first signs of kidney disease,” Dr. Bali says.

How does high blood pressure affect your kidneys?

High blood pressure makes your entire cardiovascular system work harder. That extra work puts stress on the arteries inside and around your kidneys. Over time, those arteries get narrower and weaker. They can also harden. 

When those arteries get damaged, blood flow to your kidneys is reduced. “When they don’t get enough oxygenated blood, your kidneys react by producing hormones that increase blood pressure,” Dr. Bali says. That makes them have to work harder to filter and remove fluid from your body.

It’s a continuous cycle. As your kidneys work harder, your blood pressure increases. And that increased blood pressure continues to stress your kidneys, which raises your blood pressure. This leads to a type of high blood pressure called renovascular hypertension.

This type of high blood pressure compromises the kidneys in a few different ways, including:

Reducing filtering ability

“Increased blood pressure affects tiny filtering units within the kidneys called nephrons,” says Dr. Bali. “This prevents them from properly filtering waste from the body.”

Causing protein leakage

When filters within the kidneys are damaged, they allow protein (also called albumin) to seep into urine. This is an early symptom of kidney disease. “It often appears before it shows up in bloodwork,” Dr. Bali notes.

Scarring

Damage to the filtering system causes scarring and makes the kidneys shrink. This leads to reduced kidney function.

Kidney failure

Excess stress on the kidneys eventually leads to kidney failure.

Symptoms of kidney disease and high blood pressure 

Renovascular hypertension rarely causes symptoms. This means it can cause damage to your kidneys without you knowing. That’s why checking your blood pressure regularly matters.With renovascular hypertension, it’s also important to note that you may have high blood pressure that doesn’t respond to a combination of medications, making it difficult to treat.

Lowering your risk

Keeping your kidneys as healthy as possible starts with building healthy habits. Dr. Bali recommends these simple lifestyle changes to control your blood pressure and protect your kidneys.

Be active

Physical activity can help you feel your best. Aim for 30 minutes a day most days of the week. This will help you hit a goal of 150-300 minutes of moderate intensity exercise or 75-150 minutes of vigorous exercise. Not sure where to start? Try taking a walk during your work day or after dinner.

Eat a balanced diet

Good health starts with good nutrition. To control your blood pressure and keep your kidneys healthy, eat a balanced diet. Start with a healthy mix of fruits and veggies, proteins, dairy and grains. Also avoid processed foods and things high in sodium. And to help you feel fuller longer, look for options that are high in fiber.

Take medication

If you’re taking medications for high blood pressure or other conditions, be sure to take it on a regular and consistent schedule.

Manage other health conditions

If you have other conditions that can put pressure on your kidneys, like diabetes, work with your care team to help you manage them.

Quit smoking

If you smoke, the best thing you can do for your health is to quit. Your body will thank you. If you’re not sure where to start, help is available. Talk to your healthcare provider about resources to help you stop smoking.

Maintain a healthy weight

Being overweight can cause kidney function to decline faster. It can also increase blood pressure. By maintaining a healthy weight, you can help lower your blood pressure and keep your kidneys functioning as well as possible.

Healthy habits matter

When it comes to achieving your best kidney health, small changes add up. Start by taking a few small steps. And look for the results. By putting a few healthy habits in place, you can protect your kidney health and feel your best.

See also:

Learn about nephrology and hypertension care at Geisinger
How to accurately check your blood pressure at home
Can kidney stones cause kidney failure?