What is blood pressure and why measure it?

Blood pressure is the pressure of your blood pushing on the walls of your arteries as your heart pumps blood around your body. Your blood pressure peaks when your heart contracts (called systolic blood pressure) and falls when your heart relaxes (called diastolic blood pressure). This is why your blood pressure is described using 2 numbers (for example “120 over 80”). Blood pressure is measured in units known as ‘millimetres of mercury’ or mmHg.

High blood pressure can be dangerous to your health. It is associated with many different conditions, such as heart attack, stroke, heart failure or kidney disease. 

Monitoring blood pressure important because it can help your doctor:

• diagnose high blood pressure (a condition known as hypertension)
• treat high blood pressure

Why is blood pressure monitoring at home important?

Studies show that when you measure your blood pressure at home, your measurements are more accurate than when your blood pressure is measured at a medical place.

A doctor, pharmacist or nurse may measure your blood pressure in different health places, such as:

• at your doctor’s office
• in your local pharmacy
• at a hospital or clinic

Sometimes, your blood pressure readings measured at a place providing healthcare can be higher than your actual blood pressure because it is common to feel stressed or anxious when your blood pressure is measured by a health professional.

Because blood pressure tends to go up when you’re stressed, the readings may be higher when your doctor measures your blood pressure, than when you measure it yourself in the comfort of your home. In this situation, your at-home reading may be more accurate than the reading your doctor takes. This is known as ‘white coat hypertension’, because when some people see the traditional white coat a doctor may wear, it stresses them and raises their blood pressure, even when they don’t regularly have hypertension.

For this reason, if your doctor thinks you have high or unstable blood pressure and wants to know how to best manage your condition, it is common for them to ask you to monitor your blood pressure at home.

Your blood pressure measurements taken at home helps your doctor understand your actual blood pressure. They then use this information to diagnose and form the best treatment plan for you. This helps you have better control over your blood pressure and improves your health.

Research also shows that if you monitor your blood pressure at home, you are more likely to stick to your treatment plan. Your blood pressure will then be better controlled.

How do I measure my blood pressure at home?

You can measure your blood pressure at home using a blood pressure monitor (also known as sphygmomanometer), which is a small, portable device.

There are a few simple steps to follow when you measure your blood pressure at home.

Before measuring your blood pressure:

• sit down and relax for 5 minutes in a quiet and comfortable room, avoid distractions or stressful activities

While you’re measuring your blood pressure:

• sit with your feet flat on the floor with your legs uncrossed
• keep the top half of your arm bare
• your back and arm should be supported and relaxed
• the blood pressure cuff should be wrapped around your bare arm at heart level, the bottom of the cuff should be at your elbow

Measure your blood pressure twice, one minute apart. Record both readings.

What advice do you have for measuring my blood pressure at home?

Follow these tips to get the most accurate blood pressure measurements:

• For 5 minutes before measuring, rest and sit quietly, avoid talking and distractions or extreme temperatures.
• Make sure your bladder is empty beforehand; a full bladder can raise your blood pressure.
• Measure your blood pressure at around the same time every morning and evening.
• Measure your blood pressure before taking medicines, eating or exercising.
• Do not measure your blood pressure if you are in pain, uncomfortable or stressed.
• Do not drink caffeine or smoke for 30 minutes before measuring your blood pressure.

How do I record my blood pressure measurements?

As soon as you measure your blood pressure, write down your measurement in a paper diary or on a spreadsheet that you can bring to your doctor’s appointment.

You can also get a blood pressure machine that saves your measurements. This way your doctor can check your machine to see your measurements over time. This reduces mistakes in recording your blood pressure.

You can download the Heart Foundation blood pressure measuring guide and diary to record your blood pressure.

How often should I measure my blood pressure at home?

Your health professional will guide you on how often to measure your blood pressure. Often, doctors recommend a home blood pressure check twice a day (morning and evening) for 7 days, but no less than 5 days.

Your doctor may also ask you to monitor your blood pressure:

• 7 days before an appointment at your clinic
• 4 weeks after you have changed medicines
• every 6 months as part of follow up

Remember, every person is unique. If you have been asked to monitor your blood pressure at home, ask your doctor how often and for how long they want you to check your blood pressure. 

When should I see my doctor?

You should see your doctor if you have persistent (ongoing) high blood pressure (above 140/90mmHg).

What type of blood pressure monitor should I use at home?

You should use a blood pressure monitor that has been validated and shown to be accurate at measuring blood pressure.

You can find a list of blood pressure devices that have been validated on the Menzies Institute for Medical Research website.

Your blood pressure monitor should:

• have a rubber cuff that wraps around your upper arm and fits you properly
• be automatic
• be tested to make sure it measures your blood pressure accurately
• ideally have storage memory to save your blood pressure measurements

Some blood pressure machines measure your blood pressure on your finger and/or wrist. These are not recommended.

Blood pressure monitors are available at medical supply stores, including online stores and many pharmacies. Ask your doctor or pharmacist for advice before you by one. Rebates are available from most private health insurance providers.

It is very important to follow these recommendations. A machine that has not been validated could give you a blood pressure measurement that is wrong. This can be dangerous for your health.

Resources and support

• Learn more about high blood pressure, its causes and treatment options on the Victor Chang Cardiac Research Institute
• See the Heart Foundation, ‘blood pressure action plan’ webpage to learn more about key steps you can take to manage your blood pressure and improve your health.
• Find out more about monitoring your blood pressure at home on the Hypertension Australia
• You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.

Do you prefer to read in languages other than English?

The Menzies Institute has developed a range of resources in many different community languages, to help people check if an automatic blood pressure monitor has been validated.