How to measure your blood pressure at home and use the results

September 16, 2026Mediwell Support General Practitioners Fourways mediwell

Home blood pressure measurement can help your healthcare professional understand what happens between appointments. It is useful when checking a possible diagnosis or following an existing treatment plan. Its value depends on a suitable device, a repeatable routine and sharing the results with the person responsible for your care.

A reading taken while talking, rushing or using a poorly fitting cuff can be misleading. The aim is to build a useful record, rather than chase one reassuring number. This guide is for adults; pregnancy and children’s blood pressure need their own clinical advice.

Start with a suitable monitor

An automatic upper-arm monitor with independently validated accuracy is generally preferred. The Southern African Hypertension Society links to validated-device information; ask your pharmacist or healthcare professional to help check the model and cuff size. The cuff must fit the circumference of your arm; a device labelled for general use is not automatically suitable for every person.

Take your monitor to an appointment so that someone can watch your technique and compare it with the practice equipment. Keep the instructions accessible. If you cannot use an upper-arm cuff, or the monitor repeatedly displays an irregular-heartbeat warning or error, ask for advice rather than substituting an unverified device.

Understand the two numbers

The first, or systolic, number describes pressure when the heart contracts. The second, or diastolic, number describes pressure as it relaxes between beats. Both matter, and readings are recorded in millimetres of mercury, written as mmHg.

High blood pressure often causes no noticeable symptoms. Feeling well does not tell you whether it is controlled. Over time, untreated hypertension can damage the heart, brain and kidneys, which is why a clear measurement and follow-up plan are worthwhile.

Prepare before you press start

Choose a quiet place with a supportive chair and a surface for your arm. A reading squeezed in immediately after a stressful commute or a gym session is unlikely to match a settled measurement at home.

Avoid smoking, caffeinated drinks and exercise for at least 30 minutes beforehand. Empty your bladder.
Sit quietly for at least five minutes before measuring. Keep your back supported, feet resting flat and legs uncrossed.
Place the cuff on bare skin following its instructions. Support your arm so the cuff is at heart level, with your hand relaxed.
Stay still and do not talk, text or take a call during the reading.
Take two readings at least one minute apart and record both. Use the arm your healthcare professional has advised.

If you are unsure about the position, ask for a demonstration. If a home monitor is unaffordable or unsuitable, ask your GP, local clinic or community pharmacy about another measurement plan. Confirm where the readings will be reviewed; a screening result needs appropriate follow-up.

Keep a record your GP can interpret

Follow the schedule given to you. The 2026 International Society of Hypertension guidance for Africa, hosted by the Southern African Hypertension Society, describes two readings each morning and evening for seven days before a review visit. The first day is excluded from the average. Your clinician may choose a different schedule for ongoing monitoring.

Keep all the original readings, including the first day, so the clinician can review the complete record. Write down the date, time and both numbers. Include relevant notes such as feeling dizzy, being unwell or an interrupted measurement. Do not delete a high reading simply because the next one was lower.

Ask when to measure in relation to your usual medicines and when to submit the record. Continue prescribed treatment unless your treating clinician tells you otherwise. A good reading does not mean you should stop medicine, and a high reading is not a reason to take an extra dose on your own.

What does the pattern mean?

Clinic and home measurements are interpreted differently. The African regional guidance uses a home average of at least 135 mmHg systolic or 85 mmHg diastolic as a threshold for hypertension assessment. Either number can be raised. A single reading is not the same as that average, and the threshold is not your personal treatment target.

Your GP considers your age, symptoms, other conditions and the quality of the measurements. Tell them if home readings are consistently different from clinic readings. They may review the technique or recommend a monitor worn over a longer period to clarify the pattern.

When a reading needs urgent attention

If the top number is 180 or higher, or the bottom number is 110 or higher, seek urgent professional advice the same day. South African guidance treats readings in this range as severely elevated. If you feel well, sit quietly and repeat using the correct technique, but do not let repeated testing delay contact or wait to complete a week’s record. A clinician must assess the reading and decide what care is needed.

Chest pain, severe breathlessness, new weakness, difficulty speaking, confusion or sudden visual changes require emergency assessment, especially with a very high reading. Do not delay help to repeat the measurement or wait for it to fall. Call 112 from a cellphone or 10177 for an ambulance in South Africa. These symptoms can be an emergency even without a blood pressure reading.

Repeated low readings accompanied by dizziness or fainting also need medical review. Record the symptoms and when they happen; do not adjust treatment yourself.

Bring the numbers to your next appointment

Mediwell provides medical assessments and hypertension care in Fourways. Ask reception about a GP appointment and bring your monitor, reading record and medicine list. Before leaving, agree on your individual target, future measurement schedule and what should prompt earlier contact.

This article provides general health information and does not diagnose symptoms or replace an assessment by a qualified healthcare professional.