How does a fitness bracelet measure blood pressure? Accuracy and operating principle

How does a fitness bracelet with blood pressure measurement work?

The device is equipped with touch sensors. They consist of piezoelectric elements that generate electricity when pressed. The greater the resistance of the piezo fibers, the stronger the signal. And vice versa.

The sensors measure the pulse on the wrist (the sensitivity of the sensors depends on the material of manufacture). The pulse wave presses on the piezoelements. Electronic signals appear. The software accepts them. Next, the information is processed and appears on the screen in the form that is familiar to us.

Almost all wrist gadgets display data on a display. However, there are models that lack this function. In this case, you can find out your blood pressure on your smartphone using a special application.

Top 3 devices that accurately measure blood pressure

WearFit F1 bracelet

1. Accurate measurement of heart rate and blood pressure.
2. Convenient body shape.

1. Discharges quickly.

Prices:

Bizzaro F550

1. Bright screen.
2. Measurement results can be sent by mail.

1. A little expensive for its functionality.
2. Discharges quickly.

Prices:

FitCloud CK11S bracelet

1. Fits snugly to the hand.
2. The case is durable and comes in several colors.
3. Affordable price.

1. Synchronization with the phone is lost when the signal is lost.
2. The display is unclear.
3. For an accurate indicator, you need the average of several measurements.

Prices:

How to measure blood pressure on a fitness bracelet?

Manufacturers of fitness bracelets have made the process of measuring blood pressure simple and comfortable. Owners of wrist gadgets do not need to make complex calculations or master special skills. Anyone, even a child or an elderly person, can check their blood pressure using a fitness bracelet.

You can take measurements in several ways:

1. Use a special application. Download the branded program for the bracelet to your smartphone or tablet in advance. Launch the application, open the “Blood Pressure” tab, use the “Measure” option. Function and section names may vary because each program is unique. However, the essence of this method is clear. Each manufacturer offers to measure blood pressure using an application, and it is very convenient. In the program you can view statistics for the day, week and month in the form of a graph.
2. Use the bracelet itself. On the gadget screen, select the desired function. Scroll through the options until you reach the pressure measurement. You can simply touch the screen or control the device using buttons. Select a metering option and activate the process by touching or pressing the control button.

The sensors will read information for 20-60 seconds. After this, the system will process the signals and provide an instant result. It will be displayed on the bracelet screen or saved in the proprietary application. You can measure your blood pressure several times during the day and view the results in the evening. Some models support automatic measurement at a certain interval.

Mechanism of operation

To correctly assess your performance, before starting work, you need to enter true data about height, weight and age into the fitness tracker.

The bracelet for measuring pulse and blood pressure works based on the photoplethysmographic method. In 1867, the French researcher E. J. Marey developed a method for recording pulse fluctuations in the optical density of tissues. The device measures the volume of blood flow by analyzing reflected infrared rays. The technology is tactless and non-invasive.

How to correctly measure blood pressure using a fitness bracelet?

If you want to get a reliable result, follow the basic measuring rules:

• Avoid active physical activity half an hour before measuring your blood pressure;
• During measurement, press the product firmly against your wrist (the stronger the pressure on the piezoelements, the better the signal);
• Do not talk or laugh while taking readings - take a sitting position and calm down;
• Relax the hand on which you are measuring the pressure as much as possible.

You can take measurements in other conditions, for example, immediately after a run. However, make a note of when and under what circumstances the readings were taken. The fact is that the fitness bracelet displays blood pressure results in a graph. You can track how the numbers changed throughout the day, week and even month. And if you always measured your blood pressure at rest, and once after running, this case will stand out from the overall picture. And this will be noticeable on the graph.

How to choose a smartwatch with blood pressure measurement

The market offers a huge number of smartwatch models. How to figure out which of them are really worthy of attention and which are not, if the set of functions they all have is almost the same? For answers to the most frequently asked questions regarding these “semi-medical” gadgets, Komsomolskaya Pravda turned to the chief commodity expert of the independent examination company Inves Consulting, Alexey Sigachev, and the head of the cardiology department of the hospital named after. V.V. Vinogradov of the city of Moscow, candidate of medical sciences Denis Medvedev.

How accurate is the device?

Fitness bracelets are not medical devices. Almost all manufacturers recommend using the obtained data only for informational purposes, but not for making changes in the treatment process or taking medications.

The legislation does not define the permissible error in measuring pressure. There are no official statistics on the accuracy of such devices. So the accuracy of the readings is up to the manufacturer. Some neglect this issue, while others, on the contrary, pay special attention to it. The abundance of fitness bracelets includes quite a few fairly accurate devices. Among them, for example, are products from the HerzBand and GSMIN brands.

According to unofficial statistics, the average error in blood pressure measurement is 20% with a deviation of 10-15 mmHg. Art.

Top 10 best products of 2021 according to KP

Omron Heart Guide

Omron Heart Guide Photo: Omron

Omron is a well-known manufacturer of professional measuring equipment, and the smartwatch it produces is a real blood pressure monitor that can be worn on the arm.

This thing is purely medical, in which the other smartwatch features (counting steps, displaying messages received on the smartphone) are just a decoration for the main function - measuring blood pressure. Yes, regarding this model we are talking about measurement, not calculation. This is the only smartwatch on the market with a cuff: when measured, the strap is inflated with air and inflated like a “shoulder band” from a regular blood pressure monitor.

Main characteristics

Advantages and disadvantages

Accuracy of pressure measurements, quality of materials, and the watch also has medical certificates

Lack of smart alarm, microphone and speaker

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The best fitness bracelets:

Gadgets for a healthy lifestyle

Samsung Galaxy Watch 3

Samsung Galaxy Watch 3 Photo: Samsung

The universal gadget Samsung Galaxy Watch 3, which is available in two versions (in steel and titanium cases). The “skill” of measuring pressure by the manufacturer has been perfected. Although the watch cannot be called a professional blood pressure monitor (by the way, the technical data sheet for the device strongly recommends that its readings should not be considered sufficient to make a diagnosis), according to user reviews, the Samsung Galaxy Watch 3 calculates blood pressure quite accurately. The maximum error is 5-7 units. It’s no wonder that this watch is the company’s flagship product today. True, it is not recommended to measure blood pressure with them on the go; to obtain the most accurate data, sit on a chair, place your hand on the table so that your wrist is in line with your heart and go ahead! This smartwatch will not let you down. They have a very large range of convenient functions. For example, in order to respond to a message received on the phone, the device only needs Wi-Fi. The watch connects to the smartphone automatically, including via 4G.

Main characteristics

Advantages and disadvantages

Leather strap, design, ability to make calls using the watch, lightness, a large number of functions

Using the ECG and blood pressure measurement functions is only possible with Samsung phones; users report that the application is difficult to understand

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HerzBand Elegance S5

HerzBand Elegance S5 Photo: HerzBand

This is one of the most accurate smartwatches that can measure blood pressure in the budget segment. According to user reviews, the error in the indicators is never more than 10 units. For a gadget that only “pretends” to be a medical device, this is an excellent result.

But the HerzBand Elegance S5 is still more of a biometric device than a watch that duplicates a smartphone. This model not only displays notifications about messages coming to the phone: it measures pressure both on command (if it detects deviations, it will give a signal) and in constant mode, and also analyzes sleep, the daily activity of the “owner”, and so on.

At the same time, the smart watch looks very elegant: the case is made of a special lightweight alloy, which makes it almost weightless.

Main characteristics

Advantages and disadvantages

Accurate sensors and tonometer, do not slow down, metal body, fit comfortably on the hand

Magnetic charging without a latch - it flies off, at a distance of more than 5 meters the connection with the smartphone is broken

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Asus Vivo Watch BP

Asus Vivo Watch BP Photo: Asus Vivo

The large body of the Asus Vivo Watch BP makes this smart watch something like a small copy of a smartphone with all the bells and whistles. The function of measuring pressure in them is rather an attempt by the manufacturer to expand the list of capabilities of the gadget and make it meet the trend for a healthy lifestyle. They are called “smart watches with a medical twist.” 20 seconds - and the gadget will measure the “owner’s” pulse and pressure and enter the data into memory in order, if necessary, to make recommendations on what to do to normalize well-being.

Like other smartwatches, Asus Vivo Watch BP monitors the user’s body condition around the clock and does it more or less accurately. This model will not be able to replace a professional blood pressure monitor, but it will be able to track serious pressure surges.

Main characteristics

Advantages and disadvantages

Long battery life, large numbers, simple interface

Small display, inability to replace the strap, lack of signal when readings increase, malfunctions of the pressure measurement system: it often “flies off” and the gadget has to be recalibrated

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GSMIN WP 41

GSMIN WP 41 Photo: GSMIN

Perhaps one of the best budget models. The stylish GSMIN WP 41 smart watch with a removable silicone strap will look harmonious with both a sports uniform and a formal suit. The rectangular, smooth plastic body without buttons makes them look like some kind of mini-communicator from a science-fiction film about the future.

The GSMIN WP 41 watch can be called a personal trainer and therapist who will monitor the health of its “owner” 24 hours a day, and if the smartwatch sensors detect that he has been sitting too long, the gadget will signal the need to warm up. The watch measures blood pressure and pulse both by command and automatically. GSMIN WP 41 can be programmed so that the gadget displays readings on the screen at a certain interval. Having collected data using an accurate PPG sensor and LEDs, the smart watch calculates the pressure in 2.5 minutes. Not very fast. But why rush when it comes to health?

Main characteristics

Advantages and disadvantages

Does not allow water to pass through, looks compact on the hand, has a smart alarm clock, bright screen

The pedometer can “fool” and count hand waves instead of steps, the watch can lose connection with the phone

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How to find out the measurement error?

A tonometer will help you find out the accuracy of the fitness bracelet measurements. First, use a medical device and record the result. Then measure the pressure with a wrist gadget. Compare the readings.

When doing this experiment, follow the rules:

• Measure the pressure only on your left or right hand, preferably in the same place. Please note that the pressure is higher at the wrist than at the area just above the elbow.
• Do not change your position after measuring with a tonometer. Every movement (even laughter and loud speech) affects the state of the circulatory system and blood pressure.
• Please take into account the measurement error of the tonometer. Read the indicator in the passport of the medical device in advance.

The most accurate measurement of pressure is a mechanical tonometer equipped with a phonendoscope. But such equipment is rare and requires skills to use.

Oxygen measurement in Honor Watch ES

In Honor smartwatches, the oxygen measurement function is located in the main menu and is simply called SPO2. Before starting the measurement, a laconic advice is given not to move and to turn the watch dial towards you, after which 3 seconds are given to prepare.

Honor Watch ES measures oxygen and heart rate simultaneously. If you sit still, everything will take 15-20 seconds, if you move - 45 seconds. The screen shows a circle that slowly fills with red liquid. If there were too many movements, after that the watch will remind you not to move and offer to repeat.

Prev.Next

After the measurement, data on the oxygen level and pulse are displayed, and if you remain in the same menu, the indicators change for some time. For example, during the first measurement, the final result first fell from 100% to 97%, then rose to 99% and was fixed there. The second control measurement showed a drop from 95 to 93% and an increase back to 94%.

The Honor Watch ES sensors did not respond to holding the breath, as well as to its increased frequency, showing a result of 98% in both cases.

What determines the accuracy of indicators?

The performance of different fitness bracelets may vary. What is the reason? Some are more accurate, others are not. What does this depend on?

• Cost and brand of the gadget;
• Compliance with the rules when measuring blood pressure;
• Quality of signal interpretation with special software;
• Degree of sensitivity of piezo fibers.

It’s not a fact that an expensive fitness bracelet will be the most accurate. Products for 5,000 and 10,000 rubles may not differ in anything except the brand. But bracelets from the budget segment are unlikely to show the exact result. Products costing 2,000 rubles are unlikely to be suitable for informative measurements. But if you need approximate rather than specific figures, you can choose the economy option.

On the market of wrist gadgets, you can easily find a model that is suitable in price, design and functionality. The number of bracelets that measure blood pressure is increasing every day. New brands are appearing and product functionality is expanding. There are decent models from different price categories. The most important thing is to find a suitable bracelet.

The essence of the work

The oxygen concentration in the blood is easily determined by such a device.
Sports bracelets are equipped with a number of additional functions. The wrist device helps to track the dynamics of changes in various indicators of the stability of the body. Accessories are used to determine blood pressure and pulse, oxygen concentration in the blood, count steps taken and calories burned, and also help assess sleep quality. The design of bracelets ranges from strict classics to futuristic models.

How to achieve maximum accuracy when using the tonometer function

When using a fitness bracelet to measure blood pressure, you must first calibrate the device. Ideally, you need to have an accurate medical cuff-type tonometer, with which you need to measure guaranteed accurate pressure readings in a calm state of the body. After this, you need to enter the following information into the special mobile application for the bracelet:

• accurate pressure readings in a normal resting state of the body;
• age;
• floor;
• weight.

Correct calibration is an important condition for increasing the accuracy of the fitness bracelet when measuring blood pressure. In addition, it is important to adhere to several rules:

1. Fix the bracelet strap closer to the forearm, 2-3 cm from the bend of the hand.
2. When measuring, do not speak or make sudden movements.
3. Fix the strap tightly so that the device fits snugly against the skin.
4. Place your hand at heart level, for example, place it on a tabletop.

Of course, a fitness bracelet cannot be called a full-fledged blood pressure monitor, because it gives a certain measurement error. Under no circumstances should it be used as a substitute for a medical device. At the same time, the sports device has its advantages. First of all, it is very lightweight, so you can carry it with you. It can be used to monitor approximate pressure readings during training. Having even such indicators, you can decide on the advisability of increasing or continuing current loads.

In addition, it is worth noting the huge advantage of bracelets in their ability to record measurement readings in a special application. This allows you to track your body's condition throughout the day. If you install automatic pressure measurement at a certain frequency, then such gadgets will be able to report a critical health condition.