High Blood Pressure (Hypertension): A Guide to Symptoms, Causes and Tests

Explore risk factors for high blood pressure, testing options and why it is known as the silent killer

Kimberly Hayes,

AARP

Reviewed by

Merle Myerson, M.D.

Comments

En español

Published June 03, 2024

a man getting his blood pressure checked at the doctor's office

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High Blood Pressure Guide

A staggering three-quarters of Americans over age 60 have high blood pressure, otherwise known as hypertension, putting them at increased risk for stroke, heart attack and heart failure. Men tend to have higher blood pressure rates in their younger years, but women catch up around the time of menopause.

Hypertension increases with age: Only 22.4 percent of people ages 18–39 have the condition. But those numbers rise to 54.5 percent for people age 40–59 and 74.5 percent for people 60 and over. These alarming rates are even higher for people of color, especially for African Americans. Hypertension prevalence across all ages is higher among non-Hispanic Black adults (57.1 percent) than non-Hispanic white (43.6 percent) or Hispanic (43.7 percent) adults.

What causes high blood pressure?

“The main cause of high blood pressure is aging blood vessels,” said Jordana Cohen, MD, MSCE, Associate Professor of Medicine, Renal-Electrolyte and Hypertension at the Hospital of the University of Pennsylvania. She is also chair of the Hypertension Science Committee for the American Heart Association.

Blood vessels tend to stiffen with age and becomes less flexible, which can drive up the pressure inside them. However, studies have found that there are populations of older people who don’t have high blood pressure, for example the remote South American Yanomami tribe, whose members live in near-total isolation in the rainforests in southern Venezuela and northern Brazil. They eat very little salt and fat and have a diet high in plantains, fruit and meat, and their blood pressures stay the same as when they were younger.

Research suggests that this could be related to their lower consumption of salt, and the fact that they eat a lot of potassium, Cohen said. They also have less exposure to modern-day risk factors such as pollution, stress and other diseases that are prevalent in our society, such as diabetes, heart disease and kidney disease, which all contribute to high blood pressure, Cohen added.

Understanding a blood pressure reading

Blood pressure is measured in stages, with a normal range being less than 120/80. The top number — the systolic— measures the pressure in your arteries when your heart beats. The bottom number — the diastolic — measures the pressure in your arteries when the blood is flowing back to the heart through the veins. Your blood pressure numbers are measured in millimeters of mercury (mm Hg). Stages at or above 120/80 include: elevated, stage 1 hypertension and stage 2 hypertension. A severely elevated blood pressure of 180/120 or greater can be a hypertensive crisis and could require guidance from your doctor, or in some cases, emergency care.

VIDEO: How to Read Your Own Blood Pressure

“The top number is what’s mostly considered our biggest indicator of risk,” Cohen said. It also tends to be the most responsive to treatment. The bottom number tends to be higher in younger people and then gets lower with age. Older patients can see a very wide split between their top and the bottom number, which can be concerning, Cohen said, especially if the bottom number gets too low as it can increase the risk of falls and kidney problems. “This is something that I see in my much older patients in their 80s, 90s and 100s.”

What are symptoms of high blood pressure?

Most people with hypertension shouldn’t expect to experience symptoms from high blood pressure.

“If your expectation is that you’re going to feel it, then you’re going to be somebody who’s missing it 90 percent of the time,” Cohen said.

Generally, people will not feel any symptoms of high blood pressure unless they are having the severely elevated blood pressure, which occurs when a patient’s underlying high blood pressure has accelerated to 180/120 or above and is damaging their vital organs, including the brain, heart, kidneys or eyes. In this scenario the person could face additional symptoms including sudden headache, blurred vision or vomiting, and should seek emergency medical assistance. It’s important to note that people with poorly controlled blood pressure could have readings in this higher range, but as long as they are not having other symptoms it may not be an emergency. However, they still should follow up with their doctor within a couple of days.

Measuring your blood pressure

While patients may assume a blood pressure measurement at a doctor’s office is the most accurate, that’s not always the case. To get a good blood pressure reading, it’s recommended the person sit in a quiet environment with their feet flat on the floor and their arms on a table or desk in front of them, which may not always be how you are positioned at the doctor’s office. Couple that with the stress of a doctor’s visit, and it’s easy to see how readings may not be 100 percent accurate.

White coat hypertension and masked hypertension

According to the Cleveland Clinic, between 15 to 30 percent of people have so-called white coat hypertension, which means their blood pressure is higher at a health care provider’s office, but normal at home. Estimates vary, however, with some research saying up to 50 percent or more people have white coat hypertension.

But it’s important not to discount these higher doctor’s office readings totally. “I think white coat can be used to deny high blood pressure,” said Beverly Green, M.D., senior investigator for Kaiser Permanente Washington Health Research Institute. “There’s literature showing that people with white coat hypertension are higher risk of eventually getting high blood pressure.”

At the opposite end of white coat hypertension is masked hypertension. Approximately 10 to 40 percent of people have this condition, which occurs when blood pressure is normal in the doctor’s office but high in everyday life. This can happen among people who typically smoke but avoid doing so right before a doctor’s visit. People who have sleep apnea could also be at risk, Cohen said.

The importance of home blood pressure monitoring

With home monitoring, patients can hopefully control their environment and take their readings at ideal times. (Look for guidelines on checking your blood pressure at home at the end of this article.)

It’s important to make sure you are using an accurate device, and more than two-thirds of devices on the market right now are not, Cohen said. The website validatebp.org from the American Medical Association provides a list of devices that have been validated for accuracy and includes price ranges.

It is of course important to still get your blood pressure checked at your doctor’s office and to discuss the readings you take at home with them. Some providers use an automated office blood pressure machine, which provides multiple readings over a series of intervals. This can be used in a quiet room without a medical professional present, hopefully reducing white coat hypertension.

Ambulatory blood pressure monitoring

Some patients are referred for ambulatory blood pressure monitoring, where your blood pressure is measured on a continuous basis for 24 hours as you live your daily life, even as you sleep. Your doctor will calculate the average blood pressure and also look at the range, how often readings are high or low, and if there is a “dip,” meaning a lowering of blood pressure during nighttime hours, which is normal. Ambulatory monitoring can be used for patients who have had high blood pressure readings but haven’t yet started treatment, need changes to their medications, or whose blood pressure is not responding to medications, or who have felt dizziness or have had fainting episodes.

Green has used ambulatory monitoring herself and, to her surprise, found that she had high blood pressure during the workday. “I wouldn’t have known that I had high blood pressure while at work, and there are a lot of people walking around just like that whose hypertension wouldn’t have been caught otherwise,” Green added.

It’s been shown both home monitors and the ambulatory monitors do a better job predicting heart attacks, strokes and death because they catch the variability in the average blood pressure much better than you can get from occasional blood pressure readings in the doctor’s office, Green said.

Unfortunately, ambulatory monitoring can be difficult for some patients to access as it’s a subspecialty in medicine and not available in every doctor’s office, Cohen says. But studies have shown that home blood pressure monitoring with a store-bought monitor is a good surrogate for ambulatory. “It’s not expensive and everyone can do it.”

Read more about home blood pressure monitoring.

VIDEO: How to Lower Your Blood Pressure

This high blood pressure guide shows you the science behind high blood pressure and the various factors that can play a role in high blood pressure causes and symptoms:

High blood pressure myths

Blood pressure myths about types of salt, wine intake and medications persist in popular culture. Here’s a look at six blood pressure myths, plus tips you can use to maintain a healthy blood pressure.

Read more about high blood pressure myths.

Alcohol and high blood pressure

Research has traditionally shown that heavy drinking raises your risk for high blood pressure, but now experts believe even light to moderate drinking can carry risks.

Read more about alcohol and high blood pressure.

Smoking and high blood pressure

While smoking is not a primary risk factor for high blood pressure, the habit can damage blood vessels, contributing to plaque buildup and hardening arteries. Nicotine, the addictive chemical compound in cigarettes, can also increase blood pressure.

Read more about smoking and high blood pressure.

Anxiety, stress and high blood pressure

Stress can trigger blood pressure to rise in the short-term, and if that happens frequently enough, it could damage the blood vessels, heart and kidneys, similar to what happens in people with long-term hypertension. But that’s different from saying stress or anxiety themselves produce high blood pressure.

Read more about the links between anxiety, stress and high blood pressure.

Is high blood pressure genetic?

A May 2024 study in Nature Genetics analyzed the genes of more than 1 million people of European heritage and uncovered some 113 gene variants associated with high blood pressure. While you can’t change your genes, there are lifestyle changes you can make that will likely have a much bigger impact on your risk for high blood pressure.

Read more about high blood pressure and genetics.

Medications that cause high blood pressure

Pain and migraine medicines, decongestants, corticosteroids and some herbal supplements are all examples of pills that could raise your blood pressure. Yet a 2021 study revealed that 18.5 percent of adults with hypertension were taking one or more of these medications.

Surprising causes of high blood pressure

While salt is one of the most associated risk factors for high blood pressure, there are a handful of unsuspected foods, habits and health issues that can play a role, too.

Hypertension headache

A common myth persists among some patients that they can sense their blood pressure is creeping up because they’ve started getting headaches. Yet research shows the link between high blood pressure and headaches is shaky, particularly for mild and moderate high blood pressure.

Read more about high blood pressure headaches.

Todd Detwiler

How to properly measure your blood pressure at home

Do’s:

Make sure your blood pressure monitor has been validated at validatebp.org. Confirm that the cuff fits by measuring around your upper arm and choosing a monitor with the correct cuff size. Wrist and finger monitors are not recommended due to less reliable readings.
Be in a quiet room, avoid conversation and relax for three to five minutes before taking your blood pressure.
Make sure that you’re positioned correctly: Sit at a kitchen table or a desk where your feet are flat on the floor, your back is supported and your arms are resting on the table at the level of your heart.
Put the cuff on your bare arm. If you must push your sleeve up, make sure it is loose fitting. A tight sleeve could create a tourniquet effect and raise your blood pressure.
Empty your bladder prior to a reading. Having a full bladder can raise your blood pressure, according to the AMA.
Take your blood pressure twice. People often get a surge of adrenaline when they first take the reading.
Record your blood pressure measurements, along with the time of day you took them, and discuss these results with your doctor. The AHA offers a printable blood pressure log.

Don’t

Smoke, eat or drink coffee or other caffeinated beverages at least 30 minutes before taking your blood pressure.

“We usually recommend checking two back-to-back readings about 30 seconds to a minute apart in the morning, before taking medications … and two back-to-back readings in the evening before going to bed, at least an hour after dinner, for a minimum of three days per month,” said Jordana Cohen, MD, MSCE, Associate Professor of Medicine, Renal-Electrolyte and Hypertension at the Hospital of the University of Pennsylvania. “That’s the minimum needed to get a really accurate reading.”

Doing this series of checks once a month is recommended for people currently being treated with blood pressure medication. If your blood pressure is borderline, three days of monitoring every two to three months is recommended, Cohen said.

While these are general guidelines, you should discuss how frequently to take your blood pressure with your doctor, based on your individual medical needs.

The website Targetbp.org offers additional tools and guides for measuring your blood pressure accurately at home as does the AHA.

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Kimberly Hayes is an editor-writer for AARP and has written on health and social justice issues for numerous organizations, including the National Organization for Women, the Robert Wood Johnson Foundation and the Lawyers’ Committee for Civil Rights. She previously served as editor of Native American Report.

Dr. Merle Myerson is a board-certified cardiologist with specialties in sports medicine, lipids, women’s health and prevention of cardiovascular disease.

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