How Does A Blood Pressure Monitor Work
Blood pressure is measured using a sphygmomanometer, or blood pressure monitor. It consists of an inflatable cuff thats wrapped around your arm, roughly level with your heart, and a monitoring device that measures the cuffs pressure.
The monitor measures two pressures: systolic, and diastolic. Systolic pressure is higher, occurring when your heart beats and pushes blood through the arteries, and diastolic pressure is measured when your heart is resting and filling with blood. So, for example, your blood pressure might be 120 over 80.
Blood pressure monitors may be manual or digital, but home monitors are usually digital and the whole measurement process is automatic apart from placing the cuff around your arm.
The cuff then inflates until it fits tightly around your arm, cutting off your blood flow, and then the valve opens to deflate it. As the cuff reaches your systolic pressure, blood begins to flow around your artery. This creates a vibration thats detected by the meter, which records your systolic pressure. In a traditional analogue sphygmomanometer, the blood sounds are detected by the doctor using a stethoscope.
As the cuff continues to deflate, it reaches your diastolic pressure, and the vibration stops. The meter senses this, and records the pressure again.
Normal Blood Pressure For Children
Normal BP ranges vary in children by age. The University of Iowa Stead Family Childrens Hospital provides this chart:
| Normal Blood Pressure for Children | |
|---|---|
| Systolic | |
| 112128 mm Hg | 6680 mm Hg |
What is considered healthy for your child also varies by height, age, and sex. You can use Baylor College of Medicine’s calculator to see if your childs blood pressure reading is in a healthy range.
What Affects A Blood Pressure Reading
Many things can affect a blood pressure reading, including:
- Nervousness about having your blood pressure taken. This is called white coat syndrome. As many as 1 in 3 people who have a high blood pressure reading at the doctors office may have normal blood pressure readings outside of it.1
- What you ate, drank, or did before your reading. If you smoked, drank alcohol or caffeine, or exercised within 30 minutes of having your blood pressure measured, your reading might be higher.2
- How you are sitting. Crossing your legs and letting your arm droop at your side rather than rest on a table at chest height can make your blood pressure go up.2
Its important to get an accurate blood pressure reading so that you have a clearer picture of your risk for heart disease and stroke.
A reading that says your blood pressure is lower than it actually is may give you a false sense of security about your health. A reading that says your blood pressure is higher than it actually is may lead to treatment you dont need.
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Measurement Of Force Of Arterial Blood Flow
Blood pressure is the term used to describe the force of blood as it is pumped through the arteries with each heartbeat. A blood pressure reading consists of two numbers, with the pressure measured in millimeters of mercury . A normal blood pressure reading is less than 120/80 mmHg, or 120 over 80. The systolic pressure is the pressure of the blood in the arteries when the heart beats . The diastolic pressure is the pressure of the blood in the arteries when the heart is resting .
Which Number Matters More
The answer is both. Years ago, doctors focused more on the bottom number, but it is now understood that the top number is just as important.
Both numbers can define high blood pressure and the need for treatment, Baker said.
A normal reading is less than 120 over 80. Readings above that are now considered elevated or high. The new guidelines, which were announced last November and are based on years of data, now mean that many more Americans are categorized as having high blood pressure.
High blood pressure is not a disease by itself, but its a risk factor for things like heart attack, kidney failure, stroke and more, Baker said. The new guidelines dont necessarily mean that many more people have to be on medication. They just mean a very large number of people need to be aware they have elevated or high blood pressure and need to do something about it.
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When To See The Doctor
The doctor should check your monitor at least once a year. This ensures that the measurements are accurate.
Only a doctor can diagnose you with high blood pressure. Contact your doctor if you have high readings for several days. Be sure to take your blood pressure log with you to the visit.
Hypotension is low blood pressure. This occurs when your systolic pressure is consistently below 90 or is 25 points below your normal reading. Contact your doctor if you have low readings. Hypotension can be a sign of shock, which is life threatening. Call your doctor right away if you are dizzy or lightheaded.
Huawei Watch 2 For Blood Pressure
Huawei is the second on the list for the 7 smartwatches that can measure blood pressure. The Huawei Watch 2 provides a sleek design that is ideal for both style and functionality, making it one of the best smartwatches for women. Its case material is made of metal, plastic, and stainless steel.
In terms of health monitoring and other features, the Huawei Watch 2 has an accelerometer, ambient light sensor, barometer, blood pressure monitor, gyroscope, and heart rate monitor. This accessory has a fingerprint sensor and GPS. One of the best things about this device is water-resistance, making it ideal for water adventures.
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How Blood Pressure Is Tested
Blood pressure machines vary, but they’re all a type of measuring device, which often have an arm cuff attached to it.
The cuff is usually wrapped around your upper arm and filled with air until it feels tight. This can feel uncomfortable but it only lasts a few seconds.
It’s important to relax and not talk during this time, because this is when your blood pressure is measured.
If a healthcare professional is doing this for you, they may also use a stethoscope to record your blood pressure.
An automatic device usually picks up the measurements from sensors in the arm cuff, which are sent to a digital display.
You should get the results straight away.
What Does The Systolic Blood Pressure Number Mean
When your heart beats, it squeezes and pushes blood through your arteries to the rest of your body. This force creates pressure on those blood vessels, and that’s your systolic blood pressure.
Hereâs how to understand your systolic blood pressure number:
- Normal: Below 120
- Stage 1 high blood pressure : 130-139
- Stage 2 hypertension: 140 or more
- Hypertensive crisis: 180 or more. Call 911.
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A Step By Step Guide On How To Take A Blood Pressure Measurement
Step 1
- Introduce yourself and verify patient identity using your clinical setting protocol.
- Obtain consent from the patient for the assessment and explain the procedure.
- Ensure that the patient has not had caffeine or tobacco in the last 30 minutes.
- The patient should be allowed to rest for 5 minutes following activity.
- Prepare the environment by making the room quiet, ensure patient privacy and equipment is intact and clean. Blood pressure is measured indirectly with a stethoscope or doppler and a sphygmomanometer. A sphygmomanometer includes the blood pressure cuff, connection tubes, air pump and manometer.
- Perform hand hygiene.
Step 2
Choose a measurement site:
- The preferred site is the brachial pulse site where the brachial artery runs across the antecubital fossa.
- Another site is the posterior thigh, where the popliteal artery runs behind the knee joint.
- A site should be free from pain, injury, surgical incisions, intravenous cannulas, central venous or arterial lines, areas with poor perfusion, arteriovenous fistulas or AV shunts. This reduces the risk of patient harm and helps to ensure result accuracy.
Step 3
Position the patient either sitting, standing, supine or prone depending on your choice of measurement site.
Step 4
Palpate the artery to determine the systolic BP:
Step 5
Position the stethoscope over the brachial artery and use the bell side.
Step 6
Advise the patient of the result.
Step 11
Clean and return the equipment.
Step 12
Document.
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If a doctor recommends ambulatory blood pressure monitoring, you will need to wear a blood pressure cuff for 24 hours. It’s connected to a small, portable measuring device that automatically measures your blood pressure at set times and records the readings.
Ambulatory blood pressure monitoring is used, for example, to see whether blood pressure levels vary greatly over the course of the day and night or whether they are constantly elevated. During those 24 hours, you can do all of the usual things you would otherwise do over the course of the day. If you are especially active at certain times, you can make a note in a diary. Then the doctor has a better idea of how to interpret the recorded values when evaluating them.
Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. New York: McGraw-Hill 2015.
Pschyrembel. Klinisches Wörterbuch. Berlin: De Gruyter 2017.
Stierle U . Klinikleitfaden Kardiologie. Munich: Urban und Fischer 2017.
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What Is The Significance Of Mean Arterial Pressure
Written byBel Marra HealthPublished onMarch 2, 2017
Mean arterial pressure, or MAP, is something that tells a doctor how well the body is processing oxygenated blood that is delivered to the tissues and organs. It is used to explain average blood pressure in a person during a single cardiac cycle. If MAP is low, a person can go into shock, but a high MAP can also have negative implications.
Most people are familiar with the term systolic blood pressure, but it isnt an adequate measure of perfusion . Mean arterial pressure can help determine actual pressure of blood against the arterial walls. The arteries are fibrous and muscular vessels that carry blood from the heart to other structures throughout the human body.
Fortunately, the majority of blood pressure machines in hospitals will calculate mean arterial pressure for us. In intensive care situations, MAP is often monitored with invasive tools, such as an arterial line, which is a thin catheter inserted into an artery.
Diagnosing High Or Low Blood Pressure
Only one of your numbers needs to be higher than it should be to be diagnosed with high blood pressure, and only one needs to be lower than it should be to be diagnosed with low blood pressure.
So if your top number is over 140 or the bottom number is over 90, you may be diagnosed with , regardless of the other number. If your top number is under 90 or your bottom number is under 60, you may be diagnosed with . Use the to see where your numbers sit.
If your top number is consistently higher than 140mmHg, but the bottom number is healthy – this is known as Isolated Systolic Hypertension. If the bottom number is consistently higher than 90mmHg but the top number is healthy – this is known as Isolated Diastolic Hypertension.
Making sure your readings arent a one-off
A single high reading doesnt necessarily mean you have high blood pressure, as many things can affect your blood pressure throughout the day, such as the temperature, when you last ate, and if youre feeling stressed.
Your doctor or nurse will probably want to measure your blood pressure a number of times over a few weeks to make sure the reading wasnt just a one off and that your blood pressure stays high over time.
Read about how , getting a , the you might have if you have a high blood pressure reading, and .
Read more
Find out why systolic blood pressure is the most important when it comes to keeping an eye on your numbers.
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When To See A Doctor
If a person who monitors their blood pressure at home does not see lower readings despite implementing lifestyle changes, they should get in touch with a doctor to determine the underlying cause of their high blood pressure.
A person should seek immediate medical attention if they get two readings of 180/120 mm Hg or higher within a 5-minute period, especially if they are experiencing a headache or nosebleed.
Heart Rate And Exercise
In discussions about high blood pressure, you will often see heart rate mentioned in relation to exercise. Your target heart rate is based on age and can help you monitor the intensity of your exercise.
- If you measure your heart rate before, during and after physical activity, youll notice it will increase over the course of the exercise.
- The greater the intensity of the exercise, the more your heart rate will increase.
- When you stop exercising, your heart rate does not immediately return to your normal heart rate.
- The more fit you are, the sooner your heart rate will return to normal.
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What Do The Numbers Mean
When a healthcare professional takes your blood pressure, its expressed as a measurement with two numbers, one number on top and one on the bottom , like a fraction. For example, 120/80 mm Hg.
Blood pressure is measured in millimeters of mercury. Thats what the mm/Hg stands for. Heres what the numbers mean:
- Your systolic pressure is the pressure of the blood in your arteries when your heart contracts or beats.
- Your diastolic pressure is the pressure of the blood in your arteries between beats, when your heart relaxes.
Both numbers are important in determining the state of your heart health.
Numbers greater than the ideal range may be a sign that your heart is working too hard to pump blood to the rest of your body.
For a normal reading, your blood pressure needs to show:
- a systolic pressure thats above 90 mm Hg and less than 120 mm Hg, and
- a diastolic pressure thats between 60 mm Hg and less than 80 mm Hg
The American Heart Association considers blood pressure to be within the normal range when both your systolic and diastolic numbers are in these ranges.
If youre in the normal range, no medical intervention is needed. However, its important to maintain a healthy lifestyle and moderate weight to help prevent high blood pressure from developing.
You may need to be even more mindful of your lifestyle if high blood pressure runs in your family.
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In Germany and other countries, people with high blood pressure can attend patient education courses that teach a number of things, including how to measure your blood pressure. As part of specialized disease management programs for people who have narrow coronary arteries , statutory health insurers offer additional healthcare services. These include patient education about high blood pressure. Some doctors practices don’t offer these courses, though.
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How Do I Know If My Monitor Is Accurate Or If I Am Using It Correctly
Once you buy your device, have your doctor check it for accuracy. They should check your monitor once a year. On your own, periodically check the tubing for cracks and leaks. Proper care and storage are necessary. Make sure the tubing is not twisted when you store it. Keep it away from heat.
Ask your doctor or nurse to teach you how to use your blood pressure monitor correctly. This will help you achieve good results in controlling your blood pressure.
Manual Blood Pressure Readings
Blood can only be heard through a stethoscope if it is turbulent. As the cuff is inflated, the artery is compressed, making the blood flow through the artery turbulent. When the artery is completely closed, there is no blood flow and no sound. As pressure in the cuff is reduced, the point at which the artery is open just enough to let the blood pass, is the systolic blood pressure.
This is detected by turbulent blood flow heard through the stethoscope. As pressure in the cuff is further reduced, the vessel will once again be completely open and non-turbulent. At this point, no more sound is heard and diastolic blood pressure has been reached.
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Blood Pressure Monitoring At Home
Many people monitor their blood pressure at home. They often do this to manage or treat a certain health condition. If you monitor your blood pressure at home, keep a record, or log, of the measurements. The record shows your doctor how your blood pressure changes throughout the day. If you take medicines to control your blood pressure, it will help document if they are working. Measuring your blood pressure at home is a good way to take part in managing your health.
How To Prepare For The Test
Before you measure your blood pressure:
- Rest for at least 5 minutes, 10 minutes is better, before blood pressure is taken.
- DO NOT take your blood pressure when you are under stress, have had caffeine or used tobacco in the past 30 minutes, or have exercised recently.
Take 2 or 3 readings at a sitting. Take the readings 1 minute apart. Remain seated. When checking your blood pressure on your own, note the time of the readings. Your provider may suggest that you do your readings at certain times of the day.
- You may want to take your blood pressure in the morning and at night for a week.
- This will give you at least 14 readings and will help your provider make decisions about your blood pressure treatment.
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