In this article 7 sections
Blood pressure is one of the most familiar measurements in a health check, but the two numbers can still be confusing. You may feel well when a reading is high, or wonder why the result at home differs from the one at a clinic. Understanding what is being measured helps you make sense of the pattern and know when to seek advice.
What the two numbers mean
Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps it around the body. A reading is written as two numbers, such as 120/80 mmHg, spoken as ‘120 over 80’.
The first number, called systolic pressure, measures the pressure when your heart contracts. The second, called diastolic pressure, measures it when your heart relaxes between beats. Both numbers matter: either can be higher than it should be, even when the other looks reassuring.
When blood pressure is considered high
High blood pressure, also called hypertension, means that the pressure stays raised over time. A single unexpected result usually needs checking again rather than being treated as a diagnosis on its own.
A commonly used clinic threshold is a systolic reading of 140 or higher, or a diastolic reading of 90 or higher. For readings taken at home, an average of 135 systolic or 85 diastolic or higher is commonly used. These are general adult thresholds, not a personal treatment target.
Some guidelines identify high blood pressure from 130 systolic or 80 diastolic. Your doctor considers the pattern alongside your age, medicines and conditions such as diabetes, heart disease or kidney disease. They may recommend home monitoring or a device that records your blood pressure over 24 hours before confirming the diagnosis.
Why feeling well does not tell you the whole story
High blood pressure often causes no noticeable symptoms. You cannot reliably judge it by whether you have a headache, feel tense or seem healthy. Regular measurement is how it is usually found.
Over time, uncontrolled high blood pressure can damage blood vessels and increase the risk of heart attack, stroke and kidney problems. Treatment helps reduce these risks. The aim is to protect your long-term health, even when there is nothing you can feel today.
Getting a reliable reading at home
Choose a validated automatic upper-arm monitor with a cuff that fits your arm. Ask your doctor to check your technique and compare the monitor with the clinic equipment. A cuff that is too small or too large can give an inaccurate result.
Avoid smoking, caffeine and exercise for 30 minutes beforehand, and empty your bladder. Sit quietly for at least five minutes, with your back supported, feet flat on the floor and legs uncrossed. Place the cuff on bare skin and support your arm at heart level. Stay still and avoid talking during the measurement.
Take two readings one minute apart and record both, with the date and time. Follow the schedule your doctor recommends. Keeping the conditions similar makes the readings easier to compare and more useful at your next appointment.
What everyday care can do
Reducing salt, being regularly active and working towards a healthy weight can help manage blood pressure. Think about the foods you eat often: pickles, papad, namkeen, packaged snacks and ready-made sauces can add salt alongside the amount used in cooking. Avoiding tobacco and limiting alcohol also support your health.
Some people need medicine as well as changes to daily habits. Take it as prescribed and discuss troublesome side effects with your doctor. A better reading may mean the treatment is working; it does not mean you should stop the medicine or change the dose yourself.
What a low reading can mean
Blood pressure below 90/60 mmHg is commonly described as low. Some people naturally have lower readings and feel well. Repeated dizziness, weakness, blurred vision or fainting need assessment, particularly if the symptoms are new or began after a medicine change. Share the readings and symptoms with your doctor rather than trying to correct the number yourself.
When to seek urgent help
If your systolic pressure is 180 or higher, or your diastolic pressure is 120 or higher, and you feel otherwise well, sit quietly and repeat the measurement after at least one minute. If it remains this high, contact a doctor immediately for advice.
Chest pain, severe breathlessness, sudden weakness, difficulty speaking or a sudden change in vision need emergency medical help. Do not delay to take more readings or wait for the pressure to come down. These symptoms can be an emergency even without a very high blood pressure reading.
Pregnancy and the weeks after birth need a different approach. Follow your maternity team's blood pressure advice, and seek urgent help for a severe persistent headache, vision changes or pain below the ribs. Do not wait for the general adult emergency thresholds above.