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.

How is hypertension treated in people with obesity?

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:

• adjustable gastric banding
• sleeve gastrectomy
• gastric bypass
• biliopancreatic diversion with duodenal switch

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