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Understanding the Science Behind How Smartwatches Measure Blood Pressure

smart watch measure blood pressure

High blood pressure, or hypertension, is a common health issue affecting millions of people worldwide. According to a study published in the American Heart Association Journals, more than half of U.S adults have uncontrolled high blood pressure. If untreated, this condition can result in serious health issues like heart disease, stroke, and kidney failure.

Keeping track of blood pressure levels is crucial for managing hypertension and its potential risks. This usually entails frequent trips to the doctor or other medical specialist. This method, though, can be cumbersome and inconvenient. Fortunately, advancements in technology have paved the way for more accessible and user-friendly methods of monitoring blood pressure – enter the smartwatch.

What is a Smartwatch?

A smartwatch is a wearable device designed to provide a range of features that extend beyond just telling the time. It resembles wearing a small computer on your wrist. You can receive notifications, manage music, and even make calls right from your wrist thanks to these gadgets’ ability to sync with your smartphone.

Apart from these features, a key advantage of smartwatches is their ability to track fitness and health. Your blood pressure, sleep patterns, calorie burn, and yes, even your heart rate, can all be tracked by these devices. 

How Does a Smartwatch Measure Blood Pressure?

Innovative technologies are used by smartwatches to measure blood pressure. Here is a detailed look at the techniques used:

Photoplethysmography (PPG)

This technology uses light to measure blood flow. The PPG sensor, typically found on the underside of a smartwatch, emits green LED light into the skin. Human blood absorbs green light, so when your heart beats, it pumps blood into your wrist, which then absorbs more of the green light. In between beats, less light is absorbed. By analyzing the light reflection, the sensor determines your blood flow rate, which can then be used to estimate blood pressure. An example of this technology can be seen in Fitbit devices.

Pulse Transit Time (PTT)

Some smartwatches use PTT to estimate blood pressure. With this technique, the time it takes a pulse wave to get from the heart to the blood vessels in the wrist is measured. Because the artery walls are stiffer when blood pressure is high, the pulse wave moves more quickly. Conversely, when blood pressure is low, the pulse wave travels slower. By measuring PTT, smartwatches can estimate the user’s blood pressure. Omron’s HeartGuide smartwatch employs this technology.

Heart Rate Data

There’s a correlation between heart rate and blood pressure, so some smartwatches use heart rate data to infer blood pressure. These devices use sensors to track heart rate and algorithms to translate that data into estimated blood pressure readings. For instance, Apple Watch uses its heart rate monitor in conjunction with other sensors to provide health data.

Bioimpedance Analysis

Some devices, like the InBody Band, employ a method known as bioimpedance analysis. With this method, the impedance or resistance of body tissues to the flow of a small electric signal is measured. The amount of blood in your arteries changes as your heart beats, causing variations in this electrical resistance. By tracking these changes, the smartwatch can estimate your blood pressure.

Machine Learning Algorithms

Advanced smartwatches use machine learning algorithms that learn from your daily patterns and activities to provide more accurate blood pressure readings. Over time, these algorithms can identify patterns related to your lifestyle, such as how your blood pressure changes during physical activity or stress, and adjust the readings accordingly.

Accuracy of Smartwatches in Monitoring High Blood Pressure

Smartwatches have revolutionized health monitoring, offering users the ability to check vitals, including blood pressure, at their convenience. But how precise are they, particularly when it comes to keeping an eye on high blood pressure?

While smartwatches offer a convenient way to monitor blood pressure trends, it is important to remember that they are not medical devices and should not be used to identify or treat any health issues.

Several variables, including the technology being used, where the watch is worn on the wrist, and the specific activities being carried out while measurements are being taken, can affect how accurate a smartwatch is at monitoring blood pressure.

A study from the National Library of Medicine showed that while smartwatches might offer useful information about heart rate and general trends in blood pressure, they were not as accurate as traditional cuff-based monitors for precise blood pressure measurements.

So, while smartwatches can provide valuable insights into your overall health trends and help you stay aware of your blood pressure levels, they should not replace regular check-ups with a healthcare professional or the use of medically approved blood pressure monitors for accurate readings.

Final Thoughts: The Benefits of Smartwatches in Monitoring Heart Health

The way we monitor our health has been completely transformed by smartwatches, which serve as a constant companion and record all of our vital signs. While they may not replace professional medical devices for measuring blood pressure, they still play a significant role in promoting awareness and proactive health management.

These devices provide continuous monitoring, allowing users to understand their heart rate patterns during various activities throughout the day. This data can be instrumental in identifying irregularities or changes in heart rate trends, which could be indicative of underlying health issues.

Furthermore, extra features like activity tracking, sleep analysis, and stress level detection are frequently included with smartwatches. These aspects are all interconnected with heart health. For example, regular physical activity can help lower blood pressure, good quality sleep is essential for heart health, and high stress levels can cause a spike in blood pressure. Hence, by keeping track of these areas, smartwatches contribute to a holistic approach to heart health.

In addition to heart rate and blood pressure, some advanced smartwatches can also detect atrial fibrillation (an irregular and often rapid heart rate) and send alerts about potential cardiovascular issues.

In conclusion, while smartwatches might not offer medical-grade blood pressure readings, they serve as an excellent tool for monitoring heart health, encouraging healthier habits, and potentially alerting users to significant health changes. They don’t, however, take the place of the requirement for routine checkups with a healthcare professional, so keep that in mind. The best course of action is to use the smartwatch as an additional tool in addition to expert medical guidance and treatment.


  • Diane Silva

    Diane is a travel enthusiast, content creator, and master storyteller, capturing her adventures through captivating blogs and engaging vlogs. With a passion for the great outdoors and a love for literature, she brings a unique perspective to the travel world. Whether she's exploring hidden gems or discussing the latest trends, Diane is your go-to source for all things travel and beyond.