High blood pressure can be hard to control, even when you’re following your treatment plan. If your blood pressure stays high while you’re taking three or more medications, your doctor may call it resistant hypertension. For many people, obesity can make blood pressure harder to control.

Obesity, which is usually defined as a body mass index (BMI) of 30 or higher, can make your heart work harder to pump blood. It can also affect your blood vessels and organs, including the kidneys.

These changes can raise blood pressure and make it harder to control, even with medication. Together, they may increase the risk of serious health problems, including heart disease and stroke.

Learning how obesity can contribute to resistant hypertension may help you take steps to protect your health. Here’s what you need to know about resistant hypertension and obesity.

What Is Resistant Hypertension?

Blood pressure measures how strongly your blood pushes against the walls of your arteries. When that pressure is too high, your heart has to work harder to move blood through your body. The medical term for blood pressure that’s higher than normal is hypertension.

In the United States, high blood pressure means blood pressure is consistently at or above 130/80 millimeters of mercury (mm Hg). This means either:

• Your systolic blood pressure, the first number, is 130 mm Hg or higher.
• Your diastolic blood pressure, the second number, is 80 mm Hg or higher.

High blood pressure is usually treated with lifestyle changes and medications. If you’re taking at least three blood pressure medications and still have blood pressure measurements above 140/90 mm Hg, you may have what’s called resistant hypertension.

People with resistant hypertension are often already taking the highest safe doses of antihypertensive drugs. This usually includes an angiotensin-converting enzyme inhibitor, a calcium channel blocker, and a diuretic (water pill).

High blood pressure can be either controlled or uncontrolled. Uncontrolled hypertension is when blood pressure readings are above the normal range. This means people with uncontrolled high blood pressure may or may not be taking antihypertensive medications.

However, high blood pressure that stays high during treatment isn’t always resistant hypertension. One study found that 26 percent to 48 percent of people with overweight or obesity had uncontrolled high blood pressure. Although 10 percent to 20 percent appeared to have treatment-resistant hypertension, only about 0.9 percent had true resistant hypertension.

Most cases of uncontrolled high blood pressure were linked to factors like missed medication doses and the white coat effect. With the white coat effect, a person’s blood pressure is high only during a doctor’s visit.

Obesity Can Contribute to High Blood Pressure and Treatment Resistance

Obesity is closely linked to primary hypertension. This type of high blood pressure can develop because of age, family history, or other factors.

Research has shown that between 65 percent and 78 percent of cases of primary hypertension are related to obesity. This link may happen because extra body weight can raise blood pressure.

Extra adipose tissue (fat tissue), especially around the belly, can increase inflammation. Inflammation can damage blood vessels, which can make blood pressure medications less effective. It can also cause plaque to build up in the arteries, which contributes to high blood pressure and cardiovascular disease.

Obesity can also raise blood pressure by affecting the kidneys and hormone systems that help balance fluids in the body. In people with obesity, the kidneys may hold on to too much salt, which can cause fluid buildup and higher blood pressure.

Extra body fat can also turn on hormone systems, such as the renin‐angiotensin‐aldosterone system. This system can make the body hold on to salt and water and tighten blood vessels.

Together, these factors can combine to increase blood pressure and make it harder for standard treatments to work.

Other Obesity-Related Conditions Can Make It Harder To Control Blood Pressure

People living with obesity may also have comorbidities (other health conditions) that can affect blood pressure. Having one or more of these conditions can make high blood pressure harder to treat.

Sleep Apnea

Obstructive sleep apnea (OSA) is a sleep disorder that’s closely linked to obesity. With OSA, breathing slows or stops during sleep because the airway briefly closes.

When breathing is disrupted often, it can activate the body’s stress response, which raises blood pressure. People with OSA often have high blood pressure at night, and it may rise and fall during the day, making it harder to control. OSA can also change the structure of blood vessels, causing arteries to stiffen over time.

Research has shown that OSA becomes more common as weight increases. Carrying extra weight, especially around the neck and throat, can put pressure on the airways. This can make the airway collapse more easily, reduce muscle control, and lower lung capacity.

One study noted that a 10 percent increase in body weight led to a six times higher risk of OSA. Another study by the Obesity Medicine Association found that sleep apnea was much more common in people with obesity. It affected 63 percent of men and 22 percent of women with obesity, compared with 11 percent of men and 3 percent of women without obesity.

Diabetes

People with obesity are more likely to develop type 2 diabetes mellitus. Diabetes can cause high blood pressure because it affects how the body uses insulin.

Normally, insulin helps blood vessels relax and keeps blood pressure low. But people with diabetes may have insulin resistance, which means the body does not respond well to insulin.

When the effect of insulin is weaker, it can cause blood vessels to stay tighter and blood pressure to rise. One study found that 70 percent of people with obesity had insulin resistance.

Diabetes can also affect hormones like the renin-angiotensin-aldosterone system, which can make the body hold on to salt and water. It also increases stress on the nervous system, which controls blood vessels.

Blood vessels then become stiffer, and blood pressure increases. These changes can make high blood pressure harder to control. That’s why diabetes may be a risk factor for resistant hypertension.

Kidney Conditions

Obesity is a risk factor for kidney conditions and chronic kidney disease (CKD). The kidneys play an important role in blood pressure control. Having a kidney condition, such as CKD, can raise your risk of resistant hypertension.

Healthy kidneys help remove extra fluid, balance salt, and regulate blood pressure. When the kidneys are damaged, they may not work as well.

Damaged kidneys can cause fluid and salt to build up in your body and raise the pressure inside your blood vessels. Over time, this leads to a rise in blood pressure.

High blood pressure and diabetes can also damage blood vessels in the kidneys. So, having high blood pressure can be both a cause and a symptom of CKD.

Having Obesity and High Blood Pressure Raises Your Cardiovascular Risks

Living with obesity increases your risk of heart disease and serious heart and blood vessel problems, such as heart attack, heart failure, and stroke. According to the European Society of Cardiology, cardiovascular disease causes two-thirds of deaths in people with obesity. At the same time, having resistant hypertension also raises your cardiovascular risk.

One large study found that people with obesity had an 85 percent higher risk of heart failure compared to those without overweight or obesity. The risk of heart failure may stay higher in people with obesity, even if they don’t have high blood pressure. The same study found that heart failure risk was even higher when combined with other conditions like high blood pressure and diabetes.

A study in the journal Circulation found that people with resistant hypertension had a higher risk of death than people whose blood pressure was well controlled. Resistant hypertension was linked to a 33 percent higher risk of death from heart-related causes and a 21 percent higher risk of death from any cause.

The study authors noted that people with resistant high blood pressure were more likely to have obesity, diabetes, and cardiovascular disease than those with controlled blood pressure.

Managing Resistant Hypertension With Obesity

Excess body fat contributes to high blood pressure. So, people with obesity may need more than one type of treatment to manage high blood pressure that’s hard to control. Lowering weight and improving your overall health can help you better control your blood pressure.

To manage resistant high blood pressure and obesity, your healthcare team may recommend a combination of strategies, including:

• Healthy eating — Eating healthy foods, such as fruits, vegetables, whole grains, and lean proteins, while limiting salt, can help you manage your weight and blood pressure.
• Getting more exercise — Regular physical activity like walking, swimming, or cycling can help support weight loss and lower blood pressure. If you notice any issues with your heart rate, breathing, or joint pain while exercising, talk to your doctor.
• Adjusting blood pressure medications — Your healthcare provider may suggest you adjust the medications you’re taking to better control high blood pressure. Make sure to take medications exactly as prescribed.
• Trying weight loss medications — If diet and exercise aren’t enough, weight loss drugs may help you better control your weight and blood pressure. In addition to helping with weight loss, glucagon-like peptide 1 (GLP-1) medications have been shown to lower blood pressure in people with obesity over nine months.
• Surgery — Bariatric surgery may lead to long-lasting weight loss and reduced blood pressure. Your doctor may recommend surgery if you have resistant hypertension and a BMI of 35 or higher.

If you have other health conditions that affect blood pressure, talk with your doctor. Treating these conditions may help you get better control of your high blood pressure. Work with your healthcare team to find a treatment plan that you can stick with over time.

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