Checking your blood pressure at home is an important part of managing high blood pressure. Find out how to use home monitors accurately.
By Mayo Clinic Staff
Checking your blood pressure at home is an important part of managing high blood pressure (hypertension). The American Heart Association and other organizations recommend anyone who has high blood pressure monitor his or her blood pressure at home. Home monitoring can help you keep tabs on your blood pressure in a familiar setting, make certain your medication is working, and alert you and your doctors to potential health complications.
Because blood pressure monitors are available widely and without a prescription, home monitoring is an easy step you can take to improve your condition. Before you get started, it's important to know the right technique and to find a good home blood pressure monitor.
Monitoring your blood pressure at home offers several benefits. It can:
- Help make an early diagnosis of high blood pressure. If you have prehypertension, or another condition that could contribute to high blood pressure, such as diabetes or kidney problems, home blood pressure monitoring could help your doctor diagnose high blood pressure earlier than if you have only infrequent blood pressure readings in the doctor's office.
- Help track your treatment. Home blood pressure monitoring can help people of all ages keep track of their condition — including children and teenagers who have high blood pressure. Self-monitoring provides important information between visits to your doctor. The only way to know whether your lifestyle changes or your medications are working is to check your blood pressure regularly. Keeping track of changes can help you and your health care team make decisions about your ongoing treatment strategy, such as adjusting dosages or changing medications.
- Encourage better control. Taking your own blood pressure measurements can result in better blood pressure control. You gain a stronger sense of responsibility for your health, and you may be even more motivated to control your blood pressure with an improved diet, physical activity and proper medication use.
- Cut your health care costs. Home monitoring may cut down on the number of visits you need to make to your doctor or clinic. This can reduce your overall health care costs, lower your travel expenses and save in lost wages.
Check if your blood pressure is different outside the doctor's office. Your doctor may suspect that your blood pressure goes up due to the anxiety associated with being at the doctor's office, but is otherwise normal — a condition called white coat hypertension. Monitoring blood pressure at home or work, where that kind of anxiety won't cause those spikes, can help see if you have true high blood pressure or simply white coat hypertension.
Home and workplace monitoring may also help when the opposite occurs — your blood pressure seems fine at the doctor's office, but is elevated elsewhere. This kind of high blood pressure, sometimes called masked hypertension, is more common in women and those who have cardiovascular risk factors, such as obesity, high blood cholesterol and high blood sugar.
Not everyone can track blood pressure at home. If you have an irregular heartbeat, home blood pressure monitors might not give you an accurate reading. In some cases, the type of monitor you use could depend on your physical condition. If you're overweight or very muscular, you'll need to find a monitor with a larger arm cuff. If you have hearing loss, a monitor with a digital display may be more suitable.
Talk to your doctor, nurse or other health care professional about whether home monitoring is a good option. Keep in mind that a family member or friend who is properly trained may be able to take blood pressure measurements for you.
Today, most pharmacies, medical supply stores and some Internet sites sell home blood pressure monitors. All monitors have the same basic parts — an inflatable cuff or strap, a gauge for readouts, and sometimes a stethoscope, depending on the type of monitor you choose.
- Cuff. The cuff consists of an inner layer made of rubber that fills with air and squeezes your arm. The cuff's outer layer is generally made of nylon and has a fastener to hold the cuff in place.
- Gauge. Blood pressure monitors are either digital or aneroid. The aneroid monitors have a gauge with a dial on it that points at a number related to your blood pressure. Some older gauges look similar to a thermometer and contain mercury. Mercury devices should never be used in the home.
- Stethoscope. Some blood pressure monitors come with a stethoscope. It's used to listen to the sounds your blood makes as it flows through the brachial artery in the crook of your elbow. However, without proper training, it's difficult to interpret those sounds. Digital blood pressure cuffs usually have a built-in sensor that records the information for you.
There are two types of home blood pressure monitors:
- Manual devices. Manual blood pressure monitors use a stethoscope and an inflatable arm cuff connected by a rubber tube to a gauge that records the pressure. To measure your blood pressure, you inflate the cuff that goes around your arm by pumping a bulb at one end of the tube. You then check your blood pressure with a stethoscope — listening to the sounds of blood flowing through the main artery in your upper arm as the pressure decreases in the cuff. Manual monitors are usually less expensive than digital monitors, but can be more difficult to use.
Digital devices. Digital monitors have a cuff and a gauge that records the pressure. The cuff automatically inflates at the touch of a button. These devices automatically calculate heart rate and check your blood pressure by measuring the changes in the motion of your artery as the blood flows through the artery while the cuff deflates. Some even give you an error message if you aren't wearing the cuff properly. Digital monitors also deflate automatically.
Digital monitors can be fitted on the upper arm, wrist or finger. Arm devices are the most accurate. One use for wrist monitors is for those people for whom a large upper arm cuff is too small or can't be used because of shape or pain from the pressure of the cuff when it inflates. Be sure your arm is at heart level when using a wrist monitor. Devices that measure your blood pressure at your finger are not recommended.
Talk over the choices with your doctor or nurse so that you pick the monitor that's best for your situation.
Public blood pressure machines, such as those found in pharmacies, may not be accurate. They may not have been properly maintained, and the cuff may not be the correct size for you, depending on the size of your arm. You shouldn't rely on public blood pressure machines to regularly measure your blood pressure.
Features on home blood pressure monitors can vary widely, from simple manual models to fully automated devices that allow you to send data to your doctor's office through your phone line or Internet connection. Here are some general features to consider when choosing a blood pressure monitor:
- Cuff size. Having a properly fitting cuff is the most important factor to consider when purchasing a home blood pressure monitor. Many monitors are available with different-sized cuffs to fit different-sized arms. Poorly fitting cuffs will not give accurate blood pressure measurements. Ask your doctor or nurse what cuff size you need.
- Display. The display that shows your blood pressure measurement should be clear and easy to read.
- Stethoscope. If you get a monitor with a stethoscope, you must be able to place it correctly in your ears and to clearly hear the sounds through it. You must also know how to interpret those sounds — something your doctor or nurse can teach you.
Accuracy. Check with your doctor or the manufacturer to be sure the monitor has been validated, meaning its readings are accurate and repeatable. Only validated instruments can be relied on for accurate readings. You should bring your monitor to your doctor's office to compare the measurements your monitor gives you with the measurements taken at your doctor's office. Do this yearly to make sure your monitor is still working properly.
One way to choose an accurate monitor is to check the lists of validated home blood pressure monitors available from the Dabl Educational Trust and the British Hypertension Society. These organizations have tested many types of monitors and post their findings on their websites. Keep in mind, however, that if the monitor you use doesn't appear as a recommended monitor on the lists, it doesn't mean your monitor isn't effective — only that it hasn't been reviewed by the organizations.
- Cost. Your health insurance may not cover the cost of a home blood pressure monitor. Prices can vary from as little as $25 for manual monitors to over $100 for automatic devices that come enhanced with memory and electronic printout ability.
No matter what type of home blood pressure monitor you choose, proper use requires some practice and training. Take the device to your doctor or nurse to make sure the one you've chosen is the best fit for you and to learn how to use the monitor correctly and keep it calibrated so that it continues to give you accurate readings.
You can also follow these tips to help ensure accuracy when you measure your blood pressure at home:
- Check your monitor's accuracy. Before using a monitor for the first time, have your doctor or nurse check its accuracy against the office model. Also have your doctor or nurse watch you use the device to see if you're doing it properly. If you drop the device or damage it, take it in to be checked before using it again, as it may no longer work properly.
- Measure your blood pressure twice daily. You should measure your blood pressure twice daily, once in the morning before you take any medications, and once in the evening. Each time you measure your blood pressure, take two or three readings to make sure your results are accurate. Your doctor may recommend you try to take your blood pressure at the same times of day each time you measure it. Always use your left arm when taking your blood pressure.
- Don't measure your blood pressure right after you wake up. You can prepare for the day, but don't eat breakfast or take medications before measuring your blood pressure. If you exercise after waking, take your blood pressure before exercising.
- Avoid food, caffeine, tobacco and alcohol for 30 minutes before taking a measurement. Also, go to the toilet first. A full bladder can increase blood pressure slightly.
- Sit quietly before measuring your blood pressure. When you're ready to take your blood pressure, sit quietly for three to five minutes beforehand. Sit in a comfortable position with your legs and ankles uncrossed and your back supported against a chair. Try to be calm and not think about stressful things.
- Make sure your arm is positioned properly when measuring. Rest your arm, raised to the level of your heart, on a table, desk or chair arm. You may need to place a pillow or cushion under your arm to elevate it high enough. Place the cuff on bare skin, not over clothing. Rolling up a sleeve until it tightens around your arm can result in an inaccurate reading, so you may need to slip your arm out of the sleeve.
- Don't talk while taking your blood pressure. Take a repeat reading two to three minutes after the first one to check accuracy. You can wait as little as one minute in between your readings. If your monitor doesn't automatically log blood pressure readings or heart rates, write them down in your own log.
Your blood pressure at home may be slightly lower than it is in a medical office, typically by about five points. For instance, a reading at home of 135/85 millimeters of mercury (mm Hg) is about the same as 140/90 mm Hg at the doctor's office.
Talk to your doctor about what your home blood pressure goal is. If you have diabetes, chronic kidney disease or cardiovascular disease, you may need a goal lower than that of someone without these conditions.
Blood pressure varies throughout the day, and readings are often a little higher in the morning. But contact your doctor if you have any unusual or persistent increases in your blood pressure. Also ask what reading should prompt an immediate call to the medical office. If your home reading shows that your blood pressure is higher than normal and you experience symptoms such as severe headache, chest pain, numbness, or tingling in the face or limbs, contact your medical office immediately or seek emergency treatment.
Some people record their blood pressure readings by hand. But if you have an electronic personal health record, you may choose to enter your information into the record using a computer or mobile device. This gives you the option of sharing your readings with your health care providers and family members. Some blood pressure monitors upload this data automatically.
If your blood pressure is well controlled, you may need to check it at home only a few days each month. If you're just starting home monitoring, if you're making any changes in your medications or other treatments, or if you have another health problem, such as diabetes, you may need to check it more often.
Home blood pressure monitoring is not a substitute for visits to your doctor. Even if you get normal readings, don't stop or change your medications or alter your diet without talking to your doctor first. But, with continued home monitoring, you may be able to make fewer appointments with your doctor if home monitoring shows your blood pressure is under control.
Monitoring your blood pressure at home doesn't have to be complicated or inconvenient. You might even find that you enjoy tracking your readings and that home monitoring gives you more control over your condition. And in the long run, you may risk fewer complications related to high blood pressure and enjoy a healthier life.
July 07, 2012
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