Checking your blood pressure at home, properly

High blood pressure causes no symptoms until it has already done damage, which is why it is called the silent killer and why checking matters. Home monitors have become inexpensive, and used properly they give a far better picture than a single reading taken in a clinic while you are anxious.

Used improperly, they generate numbers that are either falsely alarming or falsely reassuring. Getting the technique right takes five minutes to learn.

What the two numbers mean

The upper number is the pressure as your heart contracts and pushes blood out. The lower number is the pressure between beats, while the heart refills. Both matter, and a raised reading in either is worth attention.

A single high reading does not mean you have high blood pressure. Pressure rises with stress, pain, caffeine, a full bladder and the simple fact of having a cuff on your arm. A diagnosis rests on a pattern across several readings on different days, which is exactly what a home monitor is good at building.

How to take a reading that means something

• Sit quietly for five minutes first, in a chair with a back, feet flat on the floor and legs uncrossed.
• No caffeine, cigarettes or exercise for half an hour beforehand, and empty your bladder first.
• Rest your arm on a table so the cuff is level with your heart.
• Put the cuff on bare skin, not over a sleeve, snug enough that two fingers just fit underneath.
• Stay still and do not talk during the measurement.
• Take two readings a minute apart and record the second one.

Talking during a reading can add several points on its own, and a cuff over clothing or positioned below heart level distorts it further. These are not fussy details; they are the difference between a useful number and a meaningless one.

Choosing a monitor

Choose an upper-arm monitor rather than a wrist or finger one, which are less reliable. Look for one that has been validated for accuracy rather than simply being cheap. Make sure the cuff fits your arm — a cuff that is too small reads falsely high, which is a common and consequential error for people with larger arms.

A memory function or the ability to record two users is useful if more than one person at home will use it.

Keeping a record that helps

If your clinician has asked you to monitor, the usual approach is twice a day — morning and evening — for about a week, writing down both numbers each time. Take that record to your appointment. It is far more informative than one reading taken in a corridor, and it sometimes reveals that pressure is fine at home and only rises in clinic, which changes what should be done.

Do not check obsessively through the day. It causes anxiety, the anxiety raises the readings, and the readings cause more anxiety. A planned week is more useful than constant monitoring.

What to do about a high reading

A single raised reading means repeat it later rather than panic. A consistent pattern of raised readings means an appointment, not an emergency. But seek help immediately for a very high reading combined with chest pain, breathlessness, severe headache, visual changes, confusion or weakness down one side.

The things that lower it

Reducing salt makes a measurable difference, and in most Kenyan kitchens the salt comes as much from stock cubes, crisps and processed meats as from the salt pot. Regular activity, a healthy weight, less alcohol, stopping smoking and treating sleep problems all help. These are not alternatives to medicine where medicine is needed, but they lower the dose required and they improve everything else at the same time.

Taking a reading that means something

• No caffeine, cigarettes or exercise for half an hour beforehand.
• Empty your bladder first.
• Feet flat, legs uncrossed, back supported.
• Cuff on bare skin, level with your heart.
• Two readings a minute apart; record the second.

Questions we are asked about this

Which monitor should I buy?

An upper-arm monitor rather than a wrist or finger one, validated for accuracy, with a cuff that fits your arm. Cuff size is the detail that matters most: too small and it reads falsely high, which leads to unnecessary treatment.

My readings vary a lot. Is something wrong?

Blood pressure naturally varies through the day and with activity, stress, caffeine and a full bladder. That is why a pattern across several days matters rather than any single reading. Follow the technique carefully and record the second of two readings.

How often should I measure?

If you have been asked to monitor, twice a day for about a week before an appointment is usually the most useful approach. Checking many times a day causes anxiety, and the anxiety raises the readings.

My pressure is fine now. Can I stop my tablets?

No — it is fine because of the tablets. Blood pressure medicine controls rather than cures, and stopping it usually sees the pressure climb back within weeks. If you want to reduce or stop, that is a planned conversation with monitoring.

This article is general information from the Dantrio Pharmacy team. It cannot take the place of advice from a pharmacist or doctor who knows your medical history. If you feel seriously unwell, seek medical help straight away.