Knowing both is important and could save your life.
What Does the Systolic Blood Pressure Number Mean?
A normal systolic pressure is below 120.
What Does the Diastolic Blood Pressure Number Mean?
A normal diastolic blood pressure is lower than 80.
90 or higher is high blood pressure.
Our charts below have more details.
How Your Numbers Translate
How Is Blood Pressure Measured?
A doctor or nurse will measure your blood pressure with a small gauge attached to an inflatable cuff. It’s simple and painless.
The person taking your blood pressure wraps the cuff around your upper arm. Some cuffs go around the forearm or wrist, but often they're not as accurate.
Your doctor or nurse will use a stethoscope to listen to the blood moving through your artery.
She’ll inflate the cuff to a pressure higher than your systolic blood pressure, and it will tighten around your arm. Then she'll release it. As the cuff deflates, the first sound she hears through the stethoscope is the systolic blood pressure. It sounds like a whooshing noise. The point where this noise goes away marks the diastolic blood pressure.
In a blood pressure reading, the systolic number always comes first, and then the diastolic number. For example, your numbers may be "120 over 80" or written as 120/80.
How Often Should I Get My Blood Pressure Checked?
- If your blood pressure is normal (less than 120/80), get it checked at least every 2 years or more frequently as your doctor suggests.
- If your blood pressure is borderline high (called prehypertension) -- systolic blood pressure between 120 and 139 or diastolic blood pressure of 80 to 89 -- check it at least every year or more often as your doctor suggests. Depending on whether you have other medical issues, a “borderline” reading might be considered too high.
- If your reading is 140/90 or higher, you have high blood pressure and need to see your doctor. You may need to start medication.
Can I Check my Blood Pressure at Home?
Monitoring blood pressure at home is important for many people, especially if you have high blood pressure. This helps you and your doctor find out if your treatment is working.
Your doctor may also suggest that you check your pressure at home if she thinks you may have "white coat hypertension." It’s a real condition. The stress of being in a doctor’s office raises your blood pressure, but when you’re home, it’s normal.
Ask your doctor to recommend an easy-to-use home blood pressure monitor. Make sure the cuff fits properly. If your arm is too big for the cuff, the reading may be higher than your blood pressure really is. Ask your doctor for a larger cuff or make sure you buy a home monitor with a cuff that fits you.
You also can use a wrist blood pressure monitor, but they often aren't as accurate. Follow the directions that come with the device to make sure you are using it correctly.
No matter which type of blood pressure monitor you have, it's a good idea to take it to your doctor's office. You can compare its reading to the numbers your doctor gets. You should avoid caffeine, cigarettes, and exercise for at least 30 minutes before the test.
When you take your blood pressure at home, sit up straight in a chair and put both feet on the floor. Ask your doctor or nurse to show you the right way to position your arm so you get accurate readings.
When you check your blood pressure at home regularly, take it at the same time of day so the readings are consistent. Then, take several readings about 1 minute apart. Be sure to write down these readings.
Take your blood pressure journal to your doctor's office so you can talk about any changes in your numbers. Your doctor will decide whether you need blood pressure medications.
Even if your blood pressure is high, you probably won't have symptoms. That's why high blood pressure is often called the "silent killer." The first symptom of untreated high blood pressure may be a heart attack, stroke, or kidney damage