How Do Smart Watches Measure Blood Pressure? How reliable is it?
Knowing that your blood pressure is within normal values can be very important for your health so that you can receive the necessary health support by informing you in case of any hypertension. Here, smartwatches appear as an important tool to give you blood pressure information at any time. But the situation is not what it seems
How Smart Watches Measure Blood Pressure, Which Technology Does It Use?
Smartwatches monitor heart rate, and therefore blood pressure, in two ways.
Electrocardiography (ECG) Technology
Electrocardiography is a technology that monitors the timing and strength of electrical signals that create a heartbeat with the help of a sensor. In smartwatches, the sensor measures the time it takes a single pulse to travel from the heart to the wrist. This is also known as Pulse time (PTT).
Smartwatches like Samsung and Fitbit use this technology, using a measure called pulse transit time, which is the time between the contraction of the heart and the time the pulse reaches a certain body part, such as the wrist.
Fitbit vice president of research Eric Friedman says it measures the pulse at a time similar to pulse transit time, but at a slightly different time than Samsung does.
Photoplethysmography (PPG) Technology
Photoplethysmography is a diagram that gives information about the change in the volume of blood flowing in an area of the body close to the skin and shows the graph and the relationship between the two variables.
Photoplethysmography uses high-efficiency light sensors to show changes in blood pressure, detecting volume changes in blood flowing in arteries. Changes in volume can cause fluctuations in heart rate so that varying blood pressures are recorded.
This method requires calibrating the smartwatch initially and every four weeks with a standard blood pressure monitor to ensure the accuracy of values.
Why is it difficult to measure blood pressure with a smartwatch?
Although the current sensor in smartwatches is good enough to detect skin temperature, heart rate, and oxygen levels in the blood, it cannot show the same success in blood pressure measurements.
To measure blood pressure, doctors or other healthcare professionals will use a Blood Pressure monitor that temporarily blocks blood flow in the arm, and then measure at what pressure the blood will begin to flow back. The problem with most smartwatches is that they can’t compress and block blood flow.
Entrepreneurs continue their research to measure blood pressure accurately with smartwatches and to ensure that the measurements are at a level that can be used in medicine. Leveraging machine learning-based technologies, some companies and researchers are using photoplethysmography (PPG).showed that the sensors can be used for high-accuracy and reliable blood pressure measurements as long as the analyzes are done in one go and are not used for blood pressure.
For decades, the gold standard of blood pressure measurement was based on blocking blood flow, and optical sensors could be great for detecting heart rate, but they’re still in their infancy for monitoring blood pressure.
Some Smart Watches That Measure Blood Pressure
OMRON HeartGuide
Japanese medical device giant Omron has made the Omron Heartguide the first clinically wearable blood pressure monitor approved by the Food and Drug Administration. A sleek and elegant smartwatch, specifically for monitoring blood pressure data, it essentially creates a new category of fitness-focused smartwatches. The watch has an inflatable wristband inside the band that allows it to take blood pressure measurements at the wrist using the traditional tightening method. Unlike those that measure blood pressure with current technology, Omron’s HeartGuide is highly specialized. It is even marketed as “a wearable Blood Pressure monitor in the innovative form of a wristwatch.”
The Omron Heartguide is a smartwatch designed for use in healthcare, although its smartwatch features are still limited.
HalfSun Fitness Tracker
This attractive fitness tracker provides real-time information about heart rate and blood pressure, connected to a phone app. With this tracker, it is very important to keep the wrist extremely still while taking a reading. Blood pressure is all about getting enough sleep, and this piece comes with a sleep monitor that updates every 24 hours.
more Fitness Activity Tracker
It offers a full suite of health monitoring options, including measuring blood pressure, real-time heart rate, sleep monitoring, and more. Users can also receive a personalized and detailed in-app report that gives them a complete picture of their blood pressure and other health data.
more Fitness Activity Tracker is a fitness band with a Blood Pressure feature. This fitness tracker has a 1.14″ IPS HD color display. It has ECG and photoplethysmography (PPG) monitoring that continuously monitors your heart health and makes accurate measurements.
It also has Oxygen Saturation (SpO2) sensor, which gives the most oxygen saturation in the blood, and Heart Rate Variability (HRV) monitoring features. You can say it is a complete health monitoring device that accurately displays all the health-related data.
Yamay Fitness Tracker
This is a fairly traditional fitness tracker that includes a pedometer and calorie tracker. But it also uses state-of-the-art heart rate and Blood pressure sensors that can provide you with timely data on the state of your health.
Tracking your blood pressure is a way to track a critical aspect of your health in ways that can be not only empowering but lifesaving. According to a 2018 study published by the National Center for Biotechnology Information, “With Standing Blood Pressure monitoring, it is possible to take measurements several times a day. This will help to monitor the world’s biggest health problem and predict cardiovascular diseases.
Samsung Galaxy Wach 4
Samsung’s latest smartwatch , Galaxy Watch 4, also comes with a blood pressure monitoring feature. It has EKG, SpO2, and continuous heart rate monitoring.
This watch runs on Google Wear OS, which provides access to all Google services. You can also download apps from Play Store as the watch comes with 1.5GB RAM and 16GB ROM. It requires regular calibrations with digital blood pressure monitors.
According to The Wall Street Journal, it will reportedly inform people about trends in blood pressure — whether it’s increasing or decreasing — rather than a raw measurement that requires the calibration step used by Samsung. The Blood pressure monitoring feature on Watch 4 is not available in Turkey.
BP Doctor Pro
YHE, a Chinese startup, launched BP Doctor Pro in 2021. The device included a miniature inflatable wrist cuff. Experts state that the quality of the smartwatch’s materials and the accuracy of blood pressure measurements are high.
Huawei Watch D
Huawei has recently launched the Huawei Watch D, which seems to combine the best of both worlds. A stylish and heavy smartwatch with an inflatable blood pressure bracelet.
Huawei Band D will have a small pump that inflates a double-layer airbag inside the band. In this way, it works similarly to a standard blood pressure cuff, taking a reading from tightening the watch strap to the wearer’s wrist.
Apple Watch
The Apple Watch 8 does not have this feature. It may come as a surprise that it cannot measure blood pressure, although it has many other health features, such as being able to detect blood oxygen levels and having an app that can generate an EKG similar to a single-electrode electrocardiogram. But reading blood pressure accurately is much more complicated, and Apple is still researching how to do it to match the sleek design of its products. According to Mark Gurman, Apple won’t add a Blood Pressure monitor for the Apple Watch until 2024 at the earliest.
Should We Rely on Smartwatches to Measure Blood Pressure?
Experts are still unclear about how reliable the smartwatch-measured blood pressure can be. They note that accurately measuring blood pressure is both more important and more difficult than tracking heart rate and rhythm.
How much should we rely on smartwatches to measure blood pressure, the answer to this question is not yet clear. Accurately measuring blood pressure or any health parameter often requires professional equipment.
Cuffed standard blood pressure monitors and digital blood pressure monitors closely monitor blood movement. These monitors are also recommended by doctors for fast, reliable, and accurate data. Using a smartwatch to monitor blood pressure levels is still in development.
Smartwatches use the PAT or PTT method to monitor the time it takes for the pulse to move from the heart to the wrist. uses. Also, this method requires occasional calibration with standard Blood Pressure monitors. And if the person is doing any vigorous activity, it is not so accurate as readings can often vary more. EKG smartwatches are more accurate compared to smartwatches that use optical heart rate sensors.
The analysis, published in July, found that blood pressures calculated by the Samsung device showed “moderate to strong agreement” with pressures measured by an FDA-approved cuff.
Navar also hopes to see publicly available data on devices made by companies like Fitbit and Apple. “We’ve seen companies hold themselves to a higher standard, and I think the clinical research community is demanding that.”
Experts say, however, that the data available so far is not enough to be sure of blood pressure monitoring via a smartwatch. They think that it cannot be recommended for someone with hypertension to use it to monitor or treat high blood pressure.
As a result, doctors and researchers state that it is not yet possible for us to rely solely on smartwatches to monitor our blood pressure for medical purposes, but we can use them to get a general idea.
