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Blood Pressure: The Basics

Almost 1 in 2 Americans have high blood pressure, but one-third are unaware they have it.
Helen Massy
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Helen Massy

Undoubtedly, your blood pressure has been measured at some point. But why is it something doctors keep an eye on and measure so often?

"Blood pressure is the force exerted by blood on the walls of arteries," said Naomi Jean-Baptiste, M.D., who is a board-certified emergency medicine physician in Orlando, Florida, and the founder and CEO of Hope4Med, a metaverse platform designed to support healthcare professionals in managing burnout and maintaining their mental health and well-being.

This is an important measurement of how well your heart is working and how well blood is flowing throughout your body.

"It's measured using two numbers: systolic, when the heart pumps, and diastolic, when the heart relaxes," she added.

The measurement is taken in millimeters of mercury (mmHg) and is written as two numbers, such as 120/80; 120 is the systolic reading and 80 is diastolic.

The most common types of blood pressure machines have an arm cuff attached to them. The cuff is wrapped around your upper arm and filled with air until it tightens, which can feel uncomfortable but lasts only a few seconds.

"Your blood pressure is the most important indicator of your health," stressed Deborah Lee, M.B.Ch.B., a sexual and reproductive health specialist at Dr Fox, an online doctor and pharmacy service in the United Kingdom.

It's a very quick, simple and cost-free test to find out what your blood pressure isand it could save your life.

High blood pressure and low blood pressure

Jean-Baptiste said high blood pressure (hypertension) means the force of blood against artery walls is consistently too high. In contrast, low blood pressure (hypotension) means it's consistently too low.

"Although the normal blood pressure range varies slightly from person to person, typically a blood pressure of 120/80 is considered normal," she advised.

There is no specific number where your daily blood pressure would be considered "too low," as long as you don't encounter adverse symptoms. But for some people, low blood pressure drops can cause symptoms such as:

  • Blurred vision
  • Clammy or pale skin
  • Dehydration
  • Dizziness
  • Fainting
  • Fast, shallow breathing
  • Fatigue
  • Lack of concentration
  • Nausea
  • Shock, in severe cases

The main concern healthcare providers look for when checking your blood pressure is a high reading. This can put extra strain on your heart and blood vessels, leading to several health problems if left untreated.

"High blood pressure is a major risk factor for cardiovascular disease," Lee said.

Blood pressure is generally considered high if the systolic pressure (top number) is consistently above 130 mmHg or the diastolic pressure (bottom number) is consistently above 80 mmHg. However, it's important to note that what is considered "normal" varies based on individual circumstances, and your healthcare provider can help determine what blood pressure range is best for you.

Many people with high blood pressure have no symptoms, which is why it's vital to check your blood pressure regularly. According to Million Hearts—an organization dedicated to averting 1 million preventable cardiovascular disease events in the next five years—about 1 in 2 adults in the United States has hypertension.

Symptoms for excessively high blood pressure include:

  • Blurred vision
  • Chest pain
  • Dizziness
  • Headaches that won't go away
  • Nosebleeds
  • Shortness of breath

Don't ignore symptoms of high blood pressure, as leaving it untreated can have severe consequences.

What happens if hypertension goes untreated?

Your arteries—the blood vessels that carry blood from your heart to your organs—are stretchy to cope with your blood pressure going up and down. If you have high blood pressure, your arteries lose their stretchiness and become stiff or narrow. The narrowing makes it easier for fatty material to clog them up.

If the arteries that carry blood from your heart get damaged and clogged, this can lead to a heart attack. If this happens in arteries that carry blood to your brain, it can lead to a stroke.

If high blood pressure is left untreated, it can lead to several serious health problems over time, such as:

  • Eye damage. High blood pressure can damage the blood vessels in the eyes, causing vision problems or even blindness.
  • Heart disease. High blood pressure puts extra strain on your heart, which can lead to conditions such as heart attack, heart failure and thickening of the heart muscle.
  • Kidney disease. High blood pressure can damage the blood vessels in the kidneys, leading to kidney disease or even kidney failure.
  • Peripheral artery disease. High blood pressure can cause the arteries in the legs and feet to narrow, which can lead to pain, numbness and difficulty walking.
  • Stroke. High blood pressure can cause damage to the blood vessels in the brain, increasing the risk of stroke.

It's essential to check your blood pressure regularly and work with your healthcare provider to manage it if necessary. Lifestyle changes, such as a healthy diet, regular exercise and stress management, can often help lower blood pressure. In some cases, medication may also be necessary to manage high blood pressure.

What you need to know about blood pressure

Jean-Baptiste said it's important to know your blood pressure numbers and understand the risks associated with high or low blood pressure.

"You can take steps to manage your blood pressure through lifestyle changes, medication and regular checkups with a healthcare professional," she said.

Lee advised that the lifestyle changes you can adopt to help manage blood pressure include:

  • Controlling your weight. Try to keep within the normal body mass index (BMI) range of 18.5 to 24.9.
  • Eating a healthy diet. Full of fresh fruit and vegetables, healthy unsaturated fats, whole grains and fiber. These foods contain health-giving antioxidants, which combat oxidative stress and help ensure the endothelium (a single layer of cells lining the blood vessel walls) is functioning correctly, allowing your blood vessels to constrict and relax, ultimately governing the level of your blood pressure.
  • Engaging in regular physical exercise. Exercise has numerous positive effects on lowering blood pressure as it works the heart muscle so it pumps more efficiently. It also lowers peripheral vascular resistance, lowers the stress response of the sympathetic nervous system and reduces levels of oxidative stress.
  • Reducing your alcohol intake. Alcohol stimulates the renin-angiotensin system (RAS), increasing blood pressure. As we age, our ability to metabolize alcohol reduces, meaning our alcohol level gets higher and stays higher for longer. Alcohol is full of calories and is a great contributor to obesity, which also raises blood pressure.
  • Quitting smoking. Each cigarette you smoke causes a spike in blood pressure. Smoking also results in the production of acrolein, which is needed in the transport of HDL (good) cholesterol. As a result, smoking is directly linked to accelerated atherosclerosis, the deposition of fatty plaques in the arteries, which underpins the occurrence of major cardiac events such as heart attacks and strokes.
  • Reducing salt in your diet. Most people consume 9 to 12 grams of salt per day, which is around twice the recommended amount. We should all be using less than 5 grams per day. You can do this by cooking from scratch and not eating processed foods. Don't add salt to food and avoid eating salty snacks; choose the low-salt variety of snack food instead.

These lifestyle changes may not completely eliminate high blood pressure, but they can help reduce it and improve overall health.

"We can all help our health and longevity by making good lifestyle choices," Lee said. "Focus on things you can do."

Blood pressure and heart health resources

Educating yourself about blood pressure is a worthy goal, especially because it's estimated that 1 in 3 people who have high blood pressure are unaware of their condition. Here are some great places to start that journey:

  • The American Heart Association has tools and resources for all types of heart conditions, including hypertension.
  • Million Hearts is an initiative run by the Centers for Disease Control and Prevention (CDC) to protect and save lives impacted by heart disease and stroke in the United States.
  • The Heart Foundation is a charity dedicated to providing information on heart disease.
  • The CDC has several fact sheets on hypertension, updated on a regular basis.

The British Heart Foundation has a helpful fact sheet on blood pressure that you can download.