Uncontrolled hypertension (high blood pressure) can lead to serious health problems over time. Many people don’t realize they have high blood pressure, or they may have trouble keeping it under control — even with treatment.

Here’s a closer look at what can cause uncontrolled hypertension and some possible symptoms that may occur.

What Is Uncontrolled Hypertension?

Uncontrolled hypertension means blood pressure stays higher than the recommended range, even when it should be managed.

Some people may not know they have high blood pressure and aren’t taking steps (such as medication or lifestyle changes) to keep their numbers in a healthy range (generally below 120/80 mm Hg, which is considered normal blood pressure). About 33 percent of adults in the U.S. with high blood pressure are unaware they have it.

In other cases, people know they have high blood pressure, but treatment isn’t lowering it enough. When blood pressure remains high despite treatment, healthcare providers may call this resistant hypertension. About 20 percent of people with high blood pressure have resistant hypertension.

Healthcare providers typically define resistant hypertension as blood pressure that stays above goal despite taking three different blood pressure medications, including a diuretic (a medication that helps the body remove extra fluid and salt).

You may also be considered to have resistant hypertension if it takes four or more medications to control your blood pressure.

What Causes Uncontrolled Hypertension?

There are many reasons why blood pressure can be hard to control. Below are some common factors that may contribute to uncontrolled hypertension.

Underlying Medical Conditions

About 25 percent of people with uncontrolled or resistant hypertension have an underlying medical condition that makes it harder for them to lower their blood pressure.

Healthcare professionals often call this secondary hypertension (high blood pressure caused by another condition). When there’s no clear medical cause, it’s usually called primary or essential hypertension.

Some health conditions that may contribute to resistant hypertension include:

• Sleep apnea (a condition in which breathing repeatedly stops and starts during sleep)
• Renal (kidney) artery stenosis (narrowing of the arteries that supply the kidneys)
• Kidney failure
• Narrowing of the aorta (the body’s main artery)
• Cushing’s disease (a condition caused by high cortisol levels)
• Adrenal gland tumors (growths that can affect hormone levels)
• Hyperthyroidism (overactive thyroid)
• Hypothyroidism (underactive thyroid)
• Hyperaldosteronism (a hormone condition that affects salt balance)
• Neuroendocrine disorders (conditions affecting hormone-producing nerve cells)
• Overweight and obesity
• Metabolic syndrome (a group of conditions like high blood sugar, high blood pressure, and excess body fat)

Alcohol Use or Dependency

Drinking alcohol regularly — especially binge drinking or heavy use — can raise blood pressure and make it harder to control.

Research shows that cutting back on alcohol can help lower your blood pressure. For some people, avoiding alcohol altogether may help improve blood pressure control.

If you’re concerned about your alcohol use, consider talking with a healthcare provider or mental health professional. You can also visit FindTreatment.gov to look for support.

Medications and Supplements

Some medications and supplements can raise blood pressure or make blood pressure medications less effective.

The following medications an supplements may contribute to high blood pressure:

• Antidepressants
• Hormonal birth control pills
• Decongestants (often found in cold medicines)
• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen
• Certain herbal supplements
• Biologics (medications that target the immune system)
• Immunosuppressants (medications that reduce immune activity)
• Stimulants used to treat attention-deficit/hyperactivity disorder (ADHD)

It’s important to talk with a healthcare provider about any medications or supplements you take. Some, like caffeine pills or herbal products such as ginseng or licorice, may raise blood pressure.

Age, Sex, Race, and Family History

Several personal factors can affect your risk of high blood pressure.

High blood pressure can run in families, which suggests a genetic link. As people age, blood vessels can become stiffer (less flexible), which may raise blood pressure.

Patterns can also vary by sex and age. According to the National Heart, Lung, and Blood Institute, men are more likely to develop high blood pressure in middle age, while more women have high blood pressure as older adults.

Black adults tend to develop high blood pressure earlier and more frequently than white, Hispanic, or Asian adults, according to the National Heart, Lung, and Blood Institute. Some blood pressure medications may be less effective in Black adults than in other groups, according to the agency.

Smoking and Vaping

Smoking is a known risk factor for high blood pressure. Continuing to smoke after a diagnosis can make blood pressure harder to control.

Vaping (using e-cigarettes) may also affect heart and blood vessel health, even in younger people.

One team of researchers found that people who vaped often experienced the same negative impacts on their heart function as people who smoked traditional cigarettes even though they were younger and had been vaping for less time.

If you want help quitting smoking or vaping, talk with a healthcare provider about support options.

What Are the Symptoms of Uncontrolled Hypertension?

Most people with high blood pressure don’t experience symptoms. That’s why the condition is sometimes referred to as the silent killer. There are usually no signs your blood pressure is high until it has reached dangerous levels. At that point, you may experience a medical emergency.

Some people do experience a few warning signs before a medical emergency occurs, such as nosebleeds and occasional headaches.

If blood pressure rises to a hypertensive crisis (a severe increase in blood pressure), more serious symptoms may occur. These include:

• Dizziness
• Edema (swelling, often in the legs or feet)
• Confusion or trouble thinking clearly
• Decreased urination (making less urine than usual)
• Heart palpitations (feeling like your heart is racing or skipping beats)
• Vision changes (such as blurred or double vision)
• Signs of a stroke (such as sudden weakness, trouble speaking, or facial drooping)
• Seizures
• Severe headaches
• Shortness of breath
• Chest discomfort

Call 911 if you’re experiencing these symptoms and have a blood pressure reading of 180/120 mm Hg or higher. If you’re pregnant, seek emergency care if you have these symptoms and your blood pressure is 160/110 mm Hg or higher.

What Happens if You Have Uncontrolled Hypertension?

When blood pressure is not well managed, it can stay high without obvious symptoms. Over time, this can increase your risk of serious health problems, especially those affecting the heart and blood vessels.

Untreated hypertension can damage the walls of large arteries, such as the aorta and carotid arteries, as well as smaller vessels in organs such as the eyes. As this damage builds up, blood flow becomes less efficient, and the heart has to work harder to pump oxygen- and nutrient-rich blood throughout the body.

This added strain can affect multiple parts of the body, including the heart, brain, eyes, and kidneys.

Over time, uncontrolled hypertension can increase the risk of complications such as:

• Heart attack
• Stroke
• Coronary heart disease (a condition caused by reduced blood flow to the heart)
• Heart failure (when the heart can’t pump blood as well as it should)

It may also contribute to vision loss, chronic kidney disease (long-term kidney damage), and sexual dysfunction.

What Should You Do if You Have Uncontrolled Hypertension?

If you suspect that you have high blood pressure, follow up with your healthcare provider. They can do a physical exam, take your blood pressure, and recommend treatment options like blood pressure medications and lifestyle changes.

They also can determine what could be causing your high blood pressure and address those issues, especially if it’s caused by underlying health conditions or a particular medication.

Once you are diagnosed, it’s important to follow your healthcare provider’s instructions. This includes taking your medications as prescribed and making lifestyle changes, such as:

• Limiting alcohol
• Choosing nutritious foods
• Prioritizing sleep
• Reducing stress
• Managing your weight

Join the Conversation

On MyHeartDiseaseTeam, people share their experiences with heart disease, get advice, and find support from others who understand.

If you have uncontrolled hypertension, how did you learn about your condition and what steps have you taken to address it? Let others know in the comments below.