Patient education: Checking your blood pressure at home (The Basics)

How is blood pressure measured? — Blood pressure is usually measured with a device that goes around your upper arm. This is called a "blood pressure cuff." This is often done in a doctor's office. But some people also check their blood pressure themselves, at home or at work.

Blood pressure is explained with 2 numbers. For instance, your blood pressure might be "140 over 90." The first (top) number is the pressure inside your arteries when your heart is contracting. The second (bottom) number is the pressure inside your arteries when your heart is relaxed. The table shows how doctors and nurses define high and normal blood pressure (table 1).

If your blood pressure gets too high, it puts you at risk for heart attack, stroke, and kidney disease. High blood pressure does not usually cause symptoms. But it can be serious.

What is a home blood pressure meter? — A home blood pressure meter (or "monitor") is a device you can use to check your blood pressure yourself. It has a cuff that goes around your upper arm (figure 1). Some devices have a cuff that goes around your wrist instead. But doctors aren't sure if these work as well. The meter also has a small screen, or dial, that shows your blood pressure numbers.

There are also special meters you can wear for a day or 2. These are different because they automatically check your blood pressure throughout the day and night, even while you are sleeping. If your doctor thinks you should use 1 of these devices, they will tell you how to wear it.

Why do I need to check my blood pressure at home? — If your doctor knows or suspects that you have high blood pressure, they might want you to check it at home. There are a few reasons for this. Your doctor might want to look at:

●Whether your blood pressure measures the same at home as it did in the doctor's office

●How well your blood pressure medicines are working

●Changes in your blood pressure, for example, if it goes up and down

People who check their own blood pressure at home usually do better at keeping it low.

How do I choose a home blood pressure meter? — When choosing a home blood pressure meter, you will probably want to think about:

●Cost – Some devices cost more than others. You should also check to see if your insurance will help pay for your device.

●Size – It's important to make sure the cuff fits your arm comfortably. Your doctor or nurse can help you with this.

●How easy it is to use – You should make sure you understand how to use the device. You also need to be able to read the numbers on the screen.

You do not need a prescription to buy a home blood pressure meter. You can buy them at most pharmacies or online. Your doctor or nurse can help you choose the right device for you. They should also check your device about once every year to make sure it is working correctly.

How do I check my blood pressure at home? — Once you have a home blood pressure meter, your doctor or nurse should check it to make sure it fits you and works correctly.

When it's time to check your blood pressure:

●Go to the bathroom and empty your bladder first. Having a full bladder can temporarily increase your blood pressure, making the results inaccurate.

●Sit in a chair with your feet flat on the ground.

●Try to breathe normally and stay calm.

●Attach the cuff to your arm. Place the cuff directly on your skin, not over your clothing. The cuff should be tight enough to not slip down, but not uncomfortably tight.

●Sit and relax for about 3 to 5 minutes with the cuff on.

●Follow the directions that came with your device to start measuring your blood pressure. This might involve squeezing the bulb at the end of the tube to inflate the cuff (fill it with air). With some monitors, you press a button to inflate the cuff. When the cuff fills with air, it feels like someone is squeezing your arm, but it should not hurt. Then you will slowly deflate the cuff (let the air out of it), or it will deflate by itself. The screen or dial will show your blood pressure numbers.

●Stay seated and relax for 1 minute, then measure your blood pressure again.

How often should I check my blood pressure? — It depends. Different people need to follow different schedules. Your doctor or nurse will tell you how often to check your blood pressure, and when. Some people need to check their blood pressure twice a day, in the morning and evening.

Your doctor or nurse will probably tell you to keep track of your blood pressure for at least a few days (table 2). Then they will look at the numbers. This is because it's normal for your blood pressure to change a bit from day to day. For example, the numbers might change depending on whether you recently had caffeine, just exercised, or feel stressed. Checking your blood pressure over several days – or longer – will give your doctor or nurse a better idea of what is average for you.

How should I keep track of my blood pressure? — Some blood pressure meters will record your numbers for you, or send them to your computer or smartphone. If yours does not do this, you will need to write them down. Your doctor or nurse can help you figure out the best way to keep track of the numbers.

What if my blood pressure is high? — Your doctor or nurse will tell you what to do if your blood pressure is high when you check it at home. If you get a number that is higher than normal, measure it again to see if it is still high. If it is very high (above a certain number, which your doctor or nurse will tell you to watch out for), you should call your doctor right away.

If your blood pressure is only a little high, your doctor or nurse might tell you to keep checking it for a few more days or weeks, and then call if it does not go back down. Then they can help you decide what to do next.

More on this topic

Patient education: High blood pressure in adults (The Basics)
Patient education: Controlling your blood pressure through lifestyle (The Basics)
Patient education: High blood pressure emergencies (The Basics)
Patient education: Medicines for high blood pressure (The Basics)

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