A guide to understanding your numbers
Two numbers. One clear picture of your heart health.
High blood pressure usually causes no symptoms at all. The only way to know where you stand is to measure it — and to measure it properly. Here's what your reading means, how to take it accurately at home, and what actually helps keep it in a healthy range.
High blood pressure, or hypertension, quietly raises the pressure inside your arteries every time your heart beats. Left unmanaged over years, it's one of the biggest contributors to stroke, heart attack, heart failure and kidney disease in the UK — and most people with it feel completely fine.
UK adults are estimated to have high blood pressure at some point in adulthood.
Typical warning symptoms before a reading actually reveals a problem.
Adults in the UK are thought to have high blood pressure that hasn't yet been diagnosed.
What your reading actually means
A blood pressure reading is always written as one number over another — for example 120/80 mmHg. Both numbers matter, and neither needs to be high on its own for it to be worth a conversation with your GP.
Systolic pressure
The pressure in your arteries at the moment your heart beats and pushes blood out. This is generally the more important figure for assessing risk in adults over 50.
Diastolic pressure
The pressure in your arteries while your heart rests and refills between beats. A raised diastolic reading alone can still matter, particularly in younger adults.
Low
Often nothing to worry about. Can cause light-headedness or fainting in some people, especially on standing up quickly — worth mentioning to your GP if it happens often.
Normal
Associated with the lowest long-term risk to your heart, brain and kidneys. If you're here, the goal is simply to stay here.
Elevated
A signal rather than a diagnosis. This is the range where lifestyle changes tend to make the biggest difference, often before medication is ever needed.
High
Diagnosed as hypertension only after several consistent readings — never from a single one. Speak to your GP about a management plan.
Very high
A hypertensive crisis, particularly alongside chest pain, severe headache or blurred vision. This needs urgent medical attention, not a home fix.
Ranges shown reflect general NHS and British Heart Foundation guidance for adults, with a lower threshold of 135/85 mmHg often used for home readings rather than 140/90 mmHg in clinic. Your own healthy target may differ — always confirm it with a healthcare professional rather than relying on a single reading.
An inaccurate reading is worse than no reading at all
A few small mistakes — talking, a cold room, a cuff over your sleeve — can shift a reading by 10 mmHg or more. These five steps, in line with British and Irish Hypertension Society guidance, take a little extra care but give you a result you can actually trust and track over time.
Rest first
Sit quietly for five minutes before you begin. Avoid caffeine, exercise, and smoking for at least 30 minutes beforehand — all three can temporarily raise your reading.
Sit correctly
Back supported, feet flat on the floor, legs uncrossed. Rest your arm on a table so the cuff sits roughly level with your heart, not hanging by your side.
Position the cuff properly
Fit it directly against bare skin, around 2cm above the bend of your elbow — snug enough to stay put, loose enough to slide two fingers underneath.
Stay still and stay quiet
Don't talk, check your phone, or move your arm while the monitor is taking a reading. Movement and conversation are two of the most common causes of an inflated result.
Take two readings, one minute apart
Record both rather than just the first. Measuring at a similar time each day builds a far more useful picture than a single one-off reading.
Use a validated monitor
The British and Irish Hypertension Society maintains an up-to-date list of blood pressure monitors that have been independently tested and approved for clinical and home use. For most adults, an upper-arm cuff monitor gives a more reliable reading than a wrist or finger device — check that any monitor you buy has been clinically validated before relying on it.
What actually helps keep blood pressure in range
Research consistently shows that people who monitor their blood pressure at home achieve better control than those who don't. Pair regular checks with these everyday changes, and take medication exactly as prescribed if it's part of your plan.
Cut back on salt
Most UK adults eat well above the recommended 6g a day. Cooking from scratch and checking labels is often the single most effective dietary change you can make.
Move more
Around 150 minutes of moderate activity a week — brisk walking counts — can lower blood pressure as effectively as some medications for many people.
Mind your alcohol
Regularly drinking above recommended limits raises blood pressure over time. Cutting back is one of the faster changes to show up in your readings.
Manage your weight
Even a modest, sustained weight loss can produce a meaningful drop in blood pressure, particularly when combined with more activity.
Take medication as prescribed
If you've been prescribed blood pressure medication, don't stop or skip doses because you feel fine — hypertension has no symptoms to warn you it's returned.
Keep checking
Regular home monitoring is how you and your GP find out whether any of the above is actually working — and catch changes early.
Take the next step
How to measure your blood pressure at home
A comprehensive, step-by-step fact sheet covering technique, timing, and how to keep a reading log worth showing your GP.
Read the fact sheet → Approved monitorsClinically validated blood pressure monitors
The British & Irish Hypertension Society's list of monitors tested and approved for both clinical and home use, and how to use them properly.
See the monitor list → Talk to someoneBook an NHS health check
Adults aged 40–74 in England are eligible for a free NHS Health Check roughly every five years, which includes a blood pressure check.
Find your GP surgery →About this information — content on this site is informed by a team of hypertension professionals and support teams, drawing on guidance aligned with the British Heart Foundation and the British & Irish Hypertension Society. It's intended to help you understand and discuss your readings, not to replace individual medical advice.