Your Guide to Understanding High Blood Pressure

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.