The heart rate sensor of Apple Watch it is very accurate
If you had doubts about the operation of the heart rate sensor of the Apple Watch, now the Cupertino company is ready to tell us how it works. In a new document on the website, Apple Describe exactly how your new smartwatch does to measure your pulse, how often it does it and what factors can affect the results, for the better and for the worse.
Sensors Apple Watch are based on LED lights
Similar to other technological fitness gadgets for fitness, the Apple Watch It is based on green LED lights and a method called photoplethysmography. The blood absorbs the green light and each pulse allows a peak in the blood flow that is read from the changes in the level of absorption.
When we exercise on Apple Watch Send green light hundreds of times per second to your wrist to measure the level of light absorption by photodiodes. When we are relaxed, the method of Apple Watch It is a bit different. Just as blood absorbs green light, it also reflects red light. Every 10 minutes the infrared LEDs of the Apple they are activated to measure the heart rate. When the red LED readings are not adequate, the Apple Watch It also uses the green LED method to contrast.
Studies have shown that the green LED method is more accurate for photoplethysmography, but the Apple Watch Do not always use this method, alternating with that of the red LED. Apple It did not give any specific reason for this function, although it could be a way to save battery power, which could be one of the weak points of the company's smartwatch.
The sensor may have failures depending on external conditions
While we now know better how the heart rate sensor works, Apple recognize that the sensor is not free from faults. Like other similar sensors, the reading can be affected by cold weather, irregular movements such as boxing or tennis, and also the position of the belt. Apple recommends the use of a strap that is tight but comfortable so that the sensors are well positioned when reading the heart rate.
It should be noted that many times technological devices simply indicate that they have heart rate sensors but do not explain their operation and do not prove that accurate readings are actually thrown. Apple, although it is not free from technical problems in this field of heart rate sensors, at least it took the trouble to indicate how the sensor works Apple Watch.