Understanding your blood pressure numbers

When you go to the doctor, one of the most common vitals you’ll have checked is your blood pressure. After strapping the inflatable cuff on your arm, the nurse will tell you something like “120 over 80.” But what does that really mean?

A close up of a blood pressure reading being taken


Understanding the numbers behind your blood pressure may help control your risks of hypertension, heart disease and more. To help you feel more empowered when you visit the doctor, let’s look at what these vitals mean.

Blood pressure has two numbers:

  • The top number is your systolic blood pressure. This is the pressure in your blood vessels when your heart beats. If your number is higher, your blood is exerting more pressure against your artery walls during each contraction of your heart muscle.
  • The bottom number is your diastolic blood pressure. This is the pressure in the blood vessels in between heartbeats. A normal diastolic number is lower than 80.

For a normal, healthy adult, the top and bottom numbers usually add up to something around 120 over 80. If these numbers are too low, or too high, there might be a problem.

For example, someone with high blood pressure may have a systolic reading of 130-139 or a diastolic reading of 80-89. The higher the numbers go, the more at-risk you may be for heart attack or stroke. 

While both numbers are important, the top number (systolic) is given more attention as a way to figure out if you may be at risk for heart disease. These numbers typically increase with age but if you have an elevated reading, it can be part of a diagnosis for high blood pressure. About a third of adults in the U.S. have high blood pressure (also known as hypertension), and only 54 percent are keeping it under control.

High blood pressure is the result of more blood being pumped by your heart through narrowing arteries, which can raise your risk for heart disease and stroke. You may not experience any signs or symptoms, as the only way to know is by checking your blood pressure regularly. Readings may range from about 130 over 80 to 140 over 90 and higher.

The good news is you may be able to control high blood pressure through lifestyle changes and a healthier diet that is low in sodium, fat and cholesterol. Being active, not smoking and if needed, a prescription for medication may also help. 

Checking blood pressure might be as common as putting a thermometer in your mouth or stepping on the scale at the doctor’s office but it’s a crucial test for your health care team to help make sure you are staying healthy and thriving. If you have any questions about your blood pressure, be sure to reach out to your primary care physician.