Understanding your blood pressure numbers

Checking blood pressure at home can help you understand your numbers and talk with your provider about what they mean for your heart health.

You've probably heard your doctor or nurse rattle off some numbers after they remove the blood pressure cuff from your arm. But what do those blood pressure numbers actually mean for your health? It turns out, they mean a lot.

Blood pressure normally rises and falls throughout the day. When you're running errands, it may go up. Sitting in a comfortable chair and reading a book might make it go down. Walking into a tense meeting could cause it to spike again. The issue arises when blood pressure stays high most of the time. The higher the blood pressure, the greater the risk.

Half of Americans have high blood pressure, also known as hypertension, according to the Centers for Disease Control and Prevention. Because high blood pressure usually doesn't cause symptoms, many people are unaware they have it until complications such as heart attacks or strokes occur. That's why we commonly refer to hypertension as the "silent killer." Understanding blood pressure numbers can be a key first step in protecting your health.

What is high blood pressure?

High blood pressure occurs when blood moves through the arteries at a pressure higher than normal. When pressure remains elevated over time, it can damage the blood vessels and put extra strain on the heart, brain and kidneys.

Blood pressure is so important that it's considered one of the four key vital signs used by clinicians to assess overall health. Taking blood pressure is a normal part of a health checkup or sick visit. Everyone should have their blood pressure checked at least once a year.

To measure your blood pressure, your clinician will use a cuff that fits on your upper arm. The cuff inflates, temporarily cutting off circulation, and then deflates. The blood pressure monitor records pressure twice — once when blood first begins to flow in the artery and a second time when the heart muscle relaxes between beats.

What blood pressure numbers mean

Blood pressure is measured in millimeters of mercury (mm Hg) because the original blood pressure monitors contained mercury. Although most blood pressure monitors now use digital technology, they are still calibrated to the original standard.

When your clinician tells you your blood pressure, they will give two numbers, such as 130/80 or "one-thirty over eighty." The first or top number is the systolic pressure, which is the pressure of blood flowing out of the heart. The second or bottom number is the diastolic pressure, which is the pressure in the arteries between heartbeats. Here's what those blood pressure numbers mean:

• Normal blood pressure is anything less than 120/80.
• Elevated blood pressure is between 120 and 129 systolic and less than 80 diastolic.
• High blood pressure stage 1 is 130 to 139 systolic OR 80 to 89 diastolic.
• High blood pressure stage 2 is 140 or higher systolic OR 90 or higher diastolic.

When blood pressure rises above 180 systolic or over 120 diastolic and causes symptoms, it's called a hypertensive crisis and requires immediate contact with a doctor. Symptoms of a hypertensive crisis include sudden headache, difficulty breathing, chest pain, stomach or back pain, vision changes and trouble talking. If you experience these symptoms, call 911.

If your blood pressure is consistently above 130/80, it's important to lower it. Even if you have no symptoms, uncontrolled high blood pressure can lead to other health problems, such as heart disease, kidney disease and stroke. It may also contribute to the development of certain types of dementia and can affect sexual function.

Getting blood pressure numbers under control

In general, there is no cure for high blood pressure, but most types can be managed with lifestyle changes, medication or both. Your healthcare team will work with you to create a personalized treatment plan.

Sometimes managing stress, eating a heart-healthy diet or getting more exercise is enough to lower blood pressure. For example, losing just five percent of body weight — 10 pounds for someone who weighs 200 pounds — can reduce blood pressure by 10 points and offer additional health benefits.

Reducing salt can also help lower blood pressure. Salt (sodium) increases the volume of fluid in the blood, which stresses the heart and raises blood pressure. Most Americans consume far more than the recommended 2,300 mg or less of salt daily, mainly from packaged and processed foods. By focusing on fruits, vegetables and whole grains and preparing food from scratch at home, it becomes much easier to stay within the guidelines and lower blood pressure. Limiting alcohol and quitting smoking can also help reduce blood pressure levels.

If lifestyle changes aren't enough, your doctor might also prescribe medication. While high blood pressure increases the risk of many health problems, the good news is that both lifestyle changes and medication can lower it to healthy levels. If you're worried about high blood pressure or if it runs in your family, it's a good idea to see your doctor to have your blood pressure checked and learn what you can do to protect your health.