When it comes to smart watches, most of the most common perceptions of it are that they can read information, interact with mobile phones, and monitor heart rate and sleep. But those who know a little bit about the market know that now smart watches have developed in the direction of health monitoring. Therefore, compared with the same common functions, most of the powerful brands in the market are galloping on the track of smart watch health monitoring. With the emergence of more and more health detection smart watches, the public has gradually doubted their accuracy, so whether their detection data is accurate, and whether they all meet the standards of medical instruments? Let me answer the question for you.

One. Are heart rate and blood oxygen tests accurate?
In fact, many smart watch manufacturers are playing this slogan, and many users are worried about whether the detection is accurate or not. The current level of science and technology, these two things can be said to be very close to the level of medical instruments, but it cannot be said that they are completely the same as the results measured by medical instruments, but the deviation between the two is not large, and they can be used as a standard to measure their physical condition.

Let's now figure out how the watch measures both. Compared with other measurement methods, the biggest advantage of PPG is that this method has very low requirements for the contact between the sensor and the skin, even if it is loose enough that the sensor is not in direct contact with the skin, because too close sensor contact will bring obvious discomfort to people, and users prefer wearable devices that can be worn loosely.

PPG Detection Principle:
When a wavelength of light beam hits the skin surface of the fingertips, the contraction and expansion of blood vessels with each heartbeat affects the transmission of light (e.g., light passing through the fingertips in transmitted PPG) or reflection of light (e.g., light from near the surface of the wrist in reflected PPG). When light passes through the skin tissue and is reflected back to the light-sensitive sensor, the light is attenuated. The absorption

The disadvantage is that it is a little too "indirect", and it is easy to be disturbed by the environment in the process of collecting transmitted or reflected light signals, such as the fit degree when wearing, the wearer's own movement, body sweat and other factors that may affect photoelectric detection, and it still relies more on the algorithm to give the value, and the "estimate" component is higher.

Therefore, some smart watch products are equipped with small airbags and pressure sensors for specific blood pressure measurement needs, and use a more traditional oscillometric method close to clinical methods to accurately measure blood pressure.

The watch is mainly equipped with two detection technologies, the other one is ECG detection. When ECG is applied to smart watches, there is a big gap in scale with the monitoring methods of large devices and multiple patch electrodes that we commonly see in hospitals. The principle is to collect bioelectric signals, and the potential differences and changes in different parts of the human body can be processed by algorithms to restore a variety of values, including heart rate.

The measurement method of ECG principle on smart wearable devices is more accurate than PPG, but the coverage is relatively smaller, and the ECG itself can reflect a lot of human health data, but the current application on smart watches obviously cannot reach the sensitivity and processing power of hospital professional equipment. Therefore, the only data that can be used as an accurate and referenced ECG is heart rate.

Most of the bracelet watches on the market that only measure heart rate use green light. Some products look like red light, but in fact, this product is red light + infrared, but infrared light can't be seen. These products measure both blood oxygen and heart rate, and blood oxygen measurement must use both red and infrared light. Often on the market with green light to detect blood oxygen, the data out is basically the data stored in the system, screened out of the similar and presented, not real and reliable, only the detection of blood oxygen with red light + infrared is the real data, we have to distinguish this feature, so as not to cut leeks for some businesses.

Many people think that the health detection of smart watches is not accurate enough at all, so they think it is an IQ tax. When you measure it by the standard of medical devices, smart watches are obviously not enough, because there are very few smart watches in the world that can achieve this level. Isn't the original intention of the emergence of smart watches to facilitate the lives of the public and alleviate some of the burdens on everyone's lives, even if many detection data cannot be completely accurate, but basically can be used as a reference standard. When we choose this product, the product itself cannot fully meet the needs of the public, we only need to choose it according to our own purposes, not too harsh.