Obesity and overweight are common conditions in the United States. According to the National Heart, Lung, and Blood Institute, nearly 75 percent of all U.S. adults over 20 years old fall into one of the two categories.

Obesity generally describes an increase of fat cells in the body or an increase in their size. It can be caused by:

  • the amount and types of food you eat
  • the amount of physical activity you get
  • your genetics
  • your family history
  • the amount and quality of sleep you get

Obesity is a cause for concern as it increases your risk of many health conditions, including heart disease, diabetes, and hypertension. It’s worth noting that the effects of weight discrimination can also contribute to negative health effects.

Hypertension, or high blood pressure, is a common condition in which blood flows through your arteries at higher than usual pressures. According to the Centers for Disease Control and Prevention (CDC), high blood pressure can lead to:

  • heart disease
  • stroke
  • kidney disease
  • brain and cognitive problems
  • higher risk of dementia

About 47 percent of adults and 70 percent of people 65 years or older have high blood pressure. As many as 1 in 3 people has no idea they have it, and only 1 in 4 people has it under control.

In this article, we’ll look specifically at how obesity increases your risk of hypertension, and the steps you can take to prevent it.

Obesity can cause you to develop hypertension, or worsen it if you already have it.

A 2020 review estimates that obesity accounts for 65 to 78 percent of cases of primary hypertension. Having more fat tissue can cause complex changes in the body that combine to create or worsen hypertension. Those changes include:

  • sympathetic nervous system overactivation
  • stimulation of the renin-angiotensin-aldosterone (RAAS) system
  • changes in adipose-derived cytokines (hormones)
  • insulin resistance
  • changes to the kidneys and how they function

Obesity vs. overweight

The difference between obesity and overweight is the number of fat cells present. Doctors measure this using body mass index (BMI). Your BMI is the ratio between your weight and your height.

The Centers for Disease Control and Prevention (CDC) considers a person overweight with a BMI between 25 and 29.9. A BMI of 30 or higher indicates obesity.

Not sure what your BMI is? Use the CDC tool.

BMI is not always the best marker for obesity, though, as it doesn’t consider how people carry their weight. Your amount of visceral fat, or fat carried around your abdomen, may put you most at risk of complications. Some scientists will consider your waist size to be a better indicator.

Studies have shown that having obesity or being overweight both contribute to a higher risk of hypertension. And the risk increases along with BMI.

In one European study from 2018 of more than 7,000 people, the prevalence of hypertension increased as BMI increased. Hypertension was present in:

  • 45 percent of participants with a “normal” BMI
  • 67 percent of participants who were overweight
  • 79 to 87 percent of participants who had obesity

Ethnicity, race, and BMI

Scientists are beginning to understand the limits of BMI as a health tool. Since they were developed only for white people, BMIs may not make accurate predictions. This is especially true for Black women and Asian people.

A 2021 study recommended different BMI calculations for different ethnic groups. This was supported by experts at Harvard Health. But research has a long way to go until doctors can make accurate predictions for everyone.

In the meantime, here are some other ways to think about your health and body weight.

Obesity can cause or worsen hypertension in a variety of ways. Having obesity can also make it more difficult to treat hypertension because of other related health conditions.

The mechanisms through which obesity causes or worsens hypertension include:

  • changed hormone signaling
  • changes in the function of the sympathetic nervous system, part of the autonomic nervous system in charge of the fight-or-flight response
  • alterations in the structure and function of the kidneys

Many people who have obesity carry a higher proportion of visceral fat, meaning fat around their midsection. Visceral fat surrounds and puts pressure on the abdominal organs and more stress on the cardiovascular system.

This extra pressure often leads to resistant hypertension — uncontrolled blood pressure, according to 2015 research, despite using three or more blood pressure medications.

Renin-angiotensin-aldosterone system

A 2017 review suggests that one of the contributors to high blood pressure is the RAAS system. The RAAS helps to regulate blood volume and pressure across your whole body. When the RAAS system is not acting properly, blood pressure can remain elevated for a long time.

Another 2017 review shows that obesity causes the levels of all the hormones in the RAAS to rise. This imbalance leads to high blood pressure.

Sympathetic nervous system

The sympathetic nervous system is part of the body’s autonomic nervous system. People often call it the fight-or-flight system. It plays a key role in your metabolism and heart health.

Storing a lot of fat, especially visceral, causes higher levels of certain hormones to be secreted, according to 2015 research. These hormones cause this system to become overactive, leading to insulin resistance and even organ damage.

Renal compression

Having a lot of body fat increases the pressure on the kidneys. The kidneys are in charge of excreting excess water and regulating the level of salt in the body, which helps to regulate blood pressure. When squeezed for a long time, your kidneys become less efficient at absorbing and excreting water and salt.

According to 2019 research, if you have obesity, your kidneys also need a higher than average blood flow to function properly. This increases blood pressure.

Leptin resistance

Leptin is a hormone that makes you less hungry by telling your body you are full. This helps you maintain a moderate weight.

Some people, especially those with obesity, are resistant to leptin. They have plenty of leptin in their bodies, but it doesn’t create a sense of satisfaction because their body can’t use it in the right way.

Those with leptin resistance are more likely to eat a lot and still feel hungry, leading to weight gain. Part of the problem is that more fat cells create more leptin, so your body becomes increasingly tolerant to its effects.

Research from 2016 suggests leptin may also affect your blood pressure. If leptin isn’t working properly in your body, it can cause hypertension.

Insulin resistance

Obesity can sometimes trigger other conditions, including type 2 diabetes and prediabetes.

Your pancreas creates insulin, a hormone that allows your cells to absorb sugar and use it for energy. If you have insulin resistance, your cells don’t respond to insulin in a typical way. More insulin is needed to achieve the same effect.

Over time, your pancreas becomes overworked and can’t make enough insulin to keep your blood sugar down, such as in type 2 diabetes. When blood sugar is high for too long, it can damage or harden arteries, according to 2014 research. This leads to or worsens high blood pressure.

It’s very possible to reverse or mitigate these body changes and manage your weight and blood pressure.

Weight loss is the primary method doctors use to treat both conditions. They often recommend dietary and lifestyle changes, sometimes combined with bariatric or weight loss surgery.

Doctors usually combine weight loss (with or without surgery) with other interventions, including medications. Because medications can have side effects, doctors recommend deep lifestyle changes to manage your weight. Consistent medical checkups are a must.

Medications

Doctors can prescribe several medications to help treat obesity-related hypertension. The medications can work together, or doctors may make substitutions if one doesn’t work.

There are nine classes of antihypertensive medications that act on your body in different ways. Doctors may also consider prescribing weight loss medications on a case-by-case basis. Some medications work better in those with obesity than others.

Surgery

Doctors who treat obesity generally provide counseling on lifestyle changes. They’ll suggest a diet that includes less salt, caffeine, and alcohol. They’ll also encourage more exercise.

But it can be hard to implement and sustain these changes over a long period. Or, you may need to lose a lot of weight quickly to lower your risk of serious complications. If so, your doctor may also recommend bariatric surgery. According to a 2020 review, this is meant to help you lose enough weight.

The American Heart Association advocates for surgery to help treat obesity-related hypertension, especially if you have another related condition or a BMI over 40. Their review of studies showed that high blood pressure was completely resolved in 63 percent of people who had metabolic surgery. Even more people were able to reduce their use of blood pressure-lowering medication after surgery.

A 2019 review looked at four types of metabolic surgery currently performed in the United States:

These procedures all reduce the size of your stomach, limiting how much you can eat. The second two also bypass portions of the intestine, meaning you can’t absorb all of what you’ve eaten.

Lifestyle changes

Considerable lifestyle changes are key to establishing a moderate weight and maintaining it. The aim is to reduce fat mass while preserving lean mass.

Those changes include:

  • eating a healthy, lower calorie diet
  • limiting caffeine
  • getting active by finding an activity you enjoy and doing it regularly
  • getting a good night’s sleep
  • avoiding excessive alcohol consumption
  • quitting smoking if you do smoke and avoiding secondhand smoke
  • managing stress
  • monitoring blood pressure at home
  • getting support from family and friends

Dietary changes

Doctors may advise that people with obesity and hypertension eat a low calorie diet. According to 2016 research, this ranges from 500 to 1,500 calories per day for men and from 500 to 1,200 calories per day for women. They should also:

  • eat less salt, both added salt and the kind found in many processed foods
  • lower their intake of saturated fats and cholesterol
  • increase intake of water, fruits, fresh and raw vegetables, fish, lean meats, and whole grains

Like adults, children are now far more likely to be overweight or have obesity. A 2017 review found that the rate of obesity among children has tripled since 1980, and estimated that 17 percent of children ages 2 to 19 currently have obesity.

Children with obesity are at increased risk of high blood pressure, cardiovascular disease, and insulin resistance. They’re also at greater risk of having cardiovascular disease in adulthood.

Obesity is evaluated differently in children than it is in adults. Children up to 20 years old have obesity if they have a BMI at or higher than the 95th percentile for their age and gender. They have severe obesity if their BMI is greater than or equal to 120 percent of the 95th percentile.

As in adults, obesity in children is correlated with higher blood pressure. But children who have high blood pressure may need a larger cuff when measuring their blood pressure. This is because children often carry their weight in their arms.

The American Academy of Pediatrics recommends educating children with obesity-related hypertension about how to maintain a moderate weight and healthy lifestyle. They also recommend weight loss for children over 6 years old who have obesity, and weight maintenance only when a growing child is deemed overweight.

Children in a 2017 review who lost weight by changing their diet and physical activity patterns, and who received education and counseling, demonstrated a decrease in blood pressure.

Obesity and obesity-related hypertension are rapidly increasing among children and adults in the United States. Obesity causes and worsens high blood pressure in several ways, and doctors usually treat both conditions in tandem.

It’s very possible to manage both conditions. To recover from obesity and related conditions, doctors recommend that adults and children maintain a healthy BMI for their age and gender.

Treatment for obesity and hypertension begins with making key lifestyle changes. Other effective options may include medications and, as a last resort, surgery. For children, doctors and researchers suggest focusing on weight management and education.

Consistent checkups and medical care are very important.

Other conditions that obesity can put you at risk for are:

  • high cholesterol, a risk factor for heart disease
  • type 2 diabetes
  • breathing problems, such as asthma and sleep apnea
  • joint conditions, such as osteoarthritis and musculoskeletal discomfort
  • gallstones and gallbladder disease
  • stroke
  • many types of cancer
  • mental health conditions such as depression and anxiety

Maintaining a moderate weight and managing your blood pressure can contribute to you living a longer, healthier life.