How to Read Blood Pressure Using a Blood Pressure Chart

We’re all familiar with getting our blood pressure taken—the black cuff gets Velcro-ed around your arm, the squeezie ball is pumped until the cuff inflates, and the doctor or nurse patiently listens through the stethoscope pressed to your arm. The result is two numbers, representing your blood pressure, added to your chart. But how many of us really understand what blood pressure is and what those numbers reveal about the health of our heart? Dr. Zachry Zichittella  of Baystate Cardiology explains.

What is Normal Blood Pressure?

Blood pressure, often referred to as BP, is the force or pressure within our arteries that moves blood through your circulatory system and throughout your body.

When you’re healthy, just enough blood pressure is created to pump blood containing oxygen, antibodies, hormones, and nutrients to your vital organs. In addition to delivering essentials throughout the body, your blood also picks up and disposes waste products of metabolism.

The numbers recorded in your blood pressure reading can help your physician spot a variety of circulatory problems.

Understanding Your Blood Pressure Numbers

Blood pressure is measured with two key metrics: the top number called systolic blood pressure and the bottom number called diastolic blood pressure.

The systolic number represents how much pressure your arteries are under when your heart is squeezing.

The diastolic number represents how much pressure your arteries are under between heartbeats when your heart is relaxed.

Together, they convey how well blood is or isn’t traveling through your circulatory system.

Blood Pressure Ranges: What's Normal and What's High

Blood pressure readings fall into four categories: normal, elevated, Stage 1, Stage 2, and hypertensive crisis.

In a normal blood pressure reading, the systolic number is less than 120 and the diastolic is less than 80.

A blood pressure reading is considered elevated when the systolic number is between 120-129 and the diastolic is less than 80.

An individual with a systolic reading between 130-139 and a diastolic between 80-89 is considered to have Stage 1 high blood pressure (hypertension). A Stage 2 high blood pressure reading features a systolic number of 140 or higher and diastolic of 90 or higher.

When an individual’s systolic exceeds 180 and diastolic is 120 or higher, they are considered to be in hypertensive crisis and should seek medical attention immediately (See chart below. Swipe right for full view.)

SOURCE: American Heart Association

Why is High Blood Pressure Bad?

A high blood pressure reading indicates your heart is working too hard and that the force of the blood flowing through your arteries and veins is too high. Over time, increased pressure can cause arteries to thicken or harden and can weaken blood vessels. Left untreated, it can lead to a number of serious and potentially fatal conditions, including blood clots, heart disease, heart failure, stroke, and kidney disease. Controlling high blood pressure may also reduce your risk of dementia, according to a study called the SPRINT MIND trial.

What are the Symptoms of High Blood Pressure?

High blood pressure is often referred to as the ‘silent killer,’ and with good reason. With the exception of blood pressure in the hypertensive crisis range, high blood pressure generally has no symptoms which it’s important to check it regularly. Plus, high blood pressure is easiest to treat in the earliest (elevated) stages. (See tips for lowering your blood pressure.)

If you are in good health and have no family history of hypertension or heart disease, having your pressure checked at your annual visit should be sufficient. However, if you currently have or have had a high blood pressure diagnosis in the past or have a family history of hypertension or heart disease, you should consider monitoring your levels at home.

Choosing a Home Blood Pressure Monitor

If you are being treated for high blood pressure, home monitoring can help determine whether your medication or treatment is working. However, it’s important to purchase a quality monitor.

The American Heart Association recommends an automatic, cuff-style, bicep (upper-arm) monitor. Be sure whatever monitor you purchase comes with an appropriate-sized cuff for you (measure around your upper arm). If you are purchasing a monitor for a senior, child, or pregnant woman, look for a monitor that is validated for these conditions.

If you’re uncertain what monitor to buy, ask your doctor, pharmacist, or visit validatebp.org for a list of devices validated for clinical accuracy.

Once you’ve purchased your monitor, be sure to bring it to your next doctor appointment. This will allow your doctor to make sure you’re using the device correctly and that it is producing the same readings as the equipment in the office.

Tips for Taking Your Blood Pressure at Home

In order to ensure accurate readings from your monitor, it’s important to follow these tips:

• Do not smoke, drink caffeinated beverages or exercise 30 minutes before taking your reading
• Sit in a straight-backed chair (no sofas or recliners), legs uncrossed, and with your feet on the floor.
• Position your arm on a flat surface so that your upper arm is at heart level. The cuff should sit directly on your flesh (not over clothing) above your elbow
• Take readings at the same time every day, taking 2 to 3 readings one minute apart.
• Record all readings. Depending on your monitor, you may be able to store readings in the device or upload them to a secure website. Be sure to take your reading history with you to all doctors’ appointments.

It is important to note that home monitoring is not a substitute for regular visits to your physician. If you have been prescribed medication to lower your blood pressure, do not stop taking it without speaking to your doctor, even if your home blood pressure readings are in the normal range.

Learn more about Baystate Health’s nationally recognized heart and vascular program.