Blood pressure

High Blood Pressure

Good technique and a useful record help you and your clinician make sense of your blood pressure.

Updated

What the numbers mean

Blood pressure is the force of blood against artery walls. The top number, systolic, measures pressure during a heartbeat; the bottom number, diastolic, measures pressure between beats. Either number can be high. Hypertension often causes no symptoms, so measuring it matters.

A diagnosis uses repeated, properly measured readings and your clinical context. Home measurements can help identify a difference between office and everyday blood pressure.

How to measure at home

  1. Use a validated upper-arm monitor with a cuff that fits. Bring it to an appointment to check technique and accuracy.
  2. Avoid exercise, nicotine and caffeine for 30 minutes beforehand. Empty your bladder.
  3. Sit quietly for at least five minutes, with back supported, feet flat and legs uncrossed.
  4. Place the cuff on bare skin and support your arm at heart level. Stay quiet while measuring.
  5. Take two readings one minute apart. Record both systolic and diastolic numbers from both readings; do not select only the lowest.

How often should I check?

Agree on a schedule with your clinician. When establishing a baseline or reviewing a medication change, a short structured series is often useful: two readings in the morning and two in the evening for several days, commonly seven. Once BP is stable, your clinician may recommend less frequent checks.

Average readings help identify a pattern. They do not replace attention to symptoms or a very high reading. You do not need to wait 12 weeks to contact your clinician or make a treatment decision together.

Download a BP log or record individual measurements in My Heart Health Tracker.

Treatment and your personal target

Food choices, activity, sleep, limiting sodium and alcohol, and medication can all help. Your target and treatment depend on your overall risk, other conditions, side effects and preferences. Many people need more than one medication.

Keep an up-to-date medication list. Ask what to do if you miss a dose or feel dizzy. Do not change or stop a medicine based only on a home reading without following your care plan.

When to seek care

If systolic BP is above 180 or diastolic BP is above 120: if you have chest pain, shortness of breath, new weakness, vision changes or trouble speaking, call 911. Do not delay emergency care to collect more readings.

If you have no concerning symptoms, wait at least one minute and repeat the measurement. If it remains this high, contact your healthcare professional immediately. Severe symptoms need urgent evaluation even when BP is below these numbers.

For a persistent rise in usual readings, medication problems or recurrent lightheadedness, contact your care team according to your agreed plan.

Questions for your next visit

  • What is my BP target?
  • What schedule should I use, and when should I send my readings?
  • Which readings or symptoms mean I should call?

References and further reading

  1. AHA: Home Blood Pressure Monitoring (2025)
  2. AHA: How to measure blood pressure at home (2022)
  3. ACC/AHA: 2025 High Blood Pressure Guideline overview

Use these sources with your own clinician's advice. Recommendations depend on your health history and can change as evidence develops.