In the last article, we mainly talked about the meaning of HRV and the importance of HRV analysis to our health management. In this article, we will focus on how smart wearables use technology to monitor and analyze HRV. Professional smart watches on the market such as Apple, Huawei, Veepoo RIG, etc. can achieve accurate HRV monitoring and provide users with HRV analysis. Today we will take Veepoo RIG smart watch as an example to introduce how it realizes HRV monitoring.
Technical principle of smartwatch HRV monitoring
The working principle of smartwatches is mainly based on the method of electrocardiography, which detects R waves in QRS complexes and calculates the time between R waves (RR interval; Figure 1). It can detect heartbeats with 1 ms accuracy (1000HZ), providing very accurate HRV analysis for most people of different body sizes and age groups. The wearable devices use the principle of optical monitoring, that is: the blood, fat muscles, and bones in the human body reflect and absorb light differently, so when the LED in the watch emits green light through the tissues and arteries in the skin, due to the arteries There is blood flow in it, and the absorption of light will change. Converting optical signals into electrical signals is precisely because the absorption of light by arteries changes while the absorption of light by other tissues is basically unchanged. The obtained signals can be divided into DC signals and AC signals, and the AC signal is extracted to reflect the blood. Flow characteristics to obtain calculated heart rate values. The Veepoo RIG smartwatch uses PPG or photoplethysmography to optically detect heartbeats by measuring blood flow waves from the wrist or ear, and then calculates the heartbeat interval or IBI.
Watch wearing and monitoring method
The way the watch is worn will have a great impact on the accuracy of data monitorin，as most smart watches use optical technology for monitoring,Taking Veepoo RIG as an example, let's take a look at the correct way to wear the watch and monitor the operation.
How to wear
When wearing the monitor, it should be close to the skin. Because it uses the principle of LED green light emission, if it is not close to the skin when wearing it, the energy of the light may be weakened, affecting the penetration rate.
The watch should be worn two centimeters behind the ulnar styloid process of the wrist. According to several experiments by the Veepoo team, the smart watch is worn two centimeters behind the ulnar styloid process, the penetration rate of light to the skin will be better, and the data accuracy will be higher.
It is difficult for HRV monitoring to accurately capture HRV monitoring data during the day, because HRV monitoring detects the heartbeat value with an accuracy of 1 ms (1000HZ), which may be dominated by exercise heart rate during the day, and the time interval during the day is too short. So Veepoo RIG's HRV monitoring starts at night along with sleep.
1. You need to connect with the app.
2. After waking up, log in to the APP homepage and pull down the page to synchronize data to view HRV analysis.