A blood pressure result has two numbers. The upper number is systolic pressure—the pressure when the heart beats. The lower number is diastolic pressure—the pressure while the heart rests between beats. Readings are written in millimeters of mercury, or mm Hg.
One reading is only one moment in time. A clinician considers repeat measurements, your health history, medicines, and other factors before confirming a diagnosis or recommending a treatment plan.
Adult blood pressure categories
The categories below reflect current American Heart Association and American College of Cardiology guidance for nonpregnant adults. Pregnancy has different considerations, and your personal goal may differ based on your medical history.
| Category | Systolic (upper) | Diastolic (lower) |
|---|---|---|
| Normal | Less than 120 | and less than 80 |
| Elevated | 120–129 | and less than 80 |
| Stage 1 high blood pressure | 130–139 | or 80–89 |
| Stage 2 high blood pressure | 140 or higher | or 90 or higher |
| Severe high blood pressure | Higher than 180 | and/or higher than 120 |
When a very high reading may be an emergency
If your blood pressure is higher than 180 and/or 120 and you also have chest pain, shortness of breath, back pain, numbness, weakness, a vision change, or difficulty speaking, call 911. Do not wait for an office response.
If a repeated reading remains that high without those symptoms, contact a health care professional promptly for instructions. Do not change or stop blood pressure medicine on your own because of a home reading.
How to take a more reliable home reading
Ask your health care team whether home monitoring is appropriate for you and which schedule to follow. Use a validated automatic upper-arm monitor with a cuff that fits.
- Avoid smoking, caffeine, and exercise for 30 minutes beforehand, and empty your bladder.
- Sit quietly for at least five minutes with your back supported.
- Keep both feet flat, legs uncrossed, and the cuff on bare skin.
- Support your arm so the cuff is at heart level, and do not talk during the reading.
- Take two readings about one minute apart and record both, unless your clinician gives different instructions.
What to bring to a blood pressure visit
Bring your reading log, medicine list, and home monitor if the office asks you to. Your care team can check the cuff fit, review your technique, and decide what the pattern means for you.
Sources
- American Heart Association: Blood Pressure Explained: A Helpful Guide
- Centers for Disease Control and Prevention: Measuring Your Blood Pressure
- American Heart Association: Home Blood Pressure Monitoring