There is an error in the blood pressure measurement function of the smart watch

Issue 1236

There is an error in the blood pressure measurement function of the smart watch

Text | Li Pengge is responsible for editing | Wang Ye

The cover page executes the | Wang Ye planned | Liu Keli Proofreading | Liu Fangzuo

Smart watches that can measure blood pressure have long appeared, but the accuracy is not very high. It is difficult to say whether the recently highly called Huawei smart watch can break this deadlock, after all, the standard between the smart devices and medical devices of life is still a lot worse, and the maximum error can be 19.5mmHg.

At present, smart devices measure blood pressure in 3 ways

1. The pulse waveform of the wrist area is collected by the photoelectric sensor (PPG) to determine blood pressure. This is the cheapest and least accurate option.

2. Measured by the way of pressure pump pressurization, the price is expensive, and it is expected that Huawei may adopt this method.

3. Photoelectric + ECG comprehensive algorithm, on the basis of photoelectric signal, add metal sheet to collect ECG signal to estimate blood pressure.

At present, the listed smart bracelet has errors

None of the above methods can completely replace the measurement of the sphygmomanometer, in other words, it is just a reference value. Some data show that there is a large error in the measurement data of smart watch bracelets currently on the market. The smallest error value of shrink pressure (high voltage) is 6.4 mmHg, and the maximum error is 19.5 mmHg. The diastolic (low pressure) is similar, with the smallest error value of 5.7 mmHg and the largest reaching 12.4 mmHg. The medical standard is no more than 12.4 mmHg.

Smart watches/bracelets are not medical devices

At present, there is no certain testing standard for such health products in the industry, but it is best to believe in medical equipment for measurement accuracy. Generally speaking, the device that detects blood pressure with sensors needs to be calibrated regularly, and watches with active blood pressure measurement will also be tested for their battery life.

Compared with medical-grade wearable devices, in the case of air pressure pumps, the full power state can only be measured more than 10 times, and real-time blood pressure monitoring cannot be realized, and finally rely on the sphygmomanometer at home. At present, it is certain that Huawei's first smart watch that can measure blood pressure has passed the medical device registration test, which is still worth looking forward to.

Written in the back: Smart watches that take into account battery life and blood pressure measurement accuracy are theoretically somewhat conflicting. Blood pressure monitoring through pulse detection clearly remains to be seen, at least not in terms of accuracy. Whether the way the pneumatic pump will disturb the user is also difficult to say, relying on a separate watch to get accurate blood pressure values, should you believe it?