Checking blood pressure at home can help a healthcare professional understand readings between appointments. The equipment, preparation and way a person sits all matter. A home monitor supports clinical care; it does not establish a diagnosis on its own.
Start with a suitable monitor
The American Heart Association recommends an automatic upper-arm monitor that has been validated for accuracy. The cuff must match the size of the arm. A healthcare professional or pharmacist can help check suitability.
Take the monitor to an appointment so a professional can check the technique and compare it with the clinic's equipment. Ask how often to measure and which arm to use.
Prepare before pressing start
The AHA's measurement instructions recommend avoiding smoking, caffeine, alcohol and exercise for 30 minutes beforehand. Empty the bladder and spend at least five minutes resting quietly.
Sit with the back supported, feet flat on the floor and legs uncrossed. Rest the arm on a surface so the cuff is at heart level. Place the cuff against bare skin above the elbow, following the device's instructions. Keep still and avoid talking during the measurement.
Take two readings a minute apart and record both. A notebook or the monitor's memory can help preserve the results for an appointment.
Agree on a recording plan
A series of readings gives more context than one result. Monitoring to help confirm a diagnosis can follow a different schedule from monitoring an established condition.
For example, NICE's 2019 adult hypertension guideline describes a multi-day recording and averaging process when home monitoring is used to confirm a diagnosis. That is a clinical assessment process, not a rule that everyone must follow indefinitely.
Agree on the schedule with the treating professional and bring the record to the review. Do not stop prescribed blood pressure medicine because of home readings without speaking to that professional.
Know when urgent help is needed
For adults who are not pregnant, the AHA identifies a reading with the top number, or systolic pressure, above 180, or the bottom number, or diastolic pressure, above 120 mm Hg as severely high. Either number counts.
If this occurs with chest pain, breathlessness, back pain, numbness, weakness, vision changes or difficulty speaking, call the local emergency service immediately. Do not wait for the pressure to fall.
Warning signs of a heart attack or stroke require immediate emergency help regardless of the blood pressure reading. Do not delay calling the local emergency service to take a measurement.
If there are no new concerning symptoms, wait at least one minute and repeat the measurement. If it remains severely high, contact a healthcare professional immediately. The AHA explains this distinction in its guidance on very high readings.
This is general information for adults, not a diagnosis or treatment plan. Pregnancy requires separate clinical guidance.
