The heartbeat of children is abnormal.

The rice bracelet 6NFC also adds the function of "abnormal heartbeat". The device can continuously monitor the heart rate, and users can pay attention to their own health in advance when receiving the reminder of abnormal heart rate, which is quite accurate.

Mi band's heart rate test method is PPG. In fact, many smart watches with heart rate test may use PPG method, such as AppleWatch and moto360, and even some apps use the same method to measure, such as heart rate. Its principle is also very simple: it is to distribute photosensitive photodiodes to irradiate blood vessels through LED lamps for a period of time, and measure the heart rate according to the change of blood absorbing green light.