How Sports Wristbands Measure Our Heart Rate

The miniaturization of technology has allowed over the years that our electronic devices may have a greater number of uses in less space. The sports wristbands are already able to measure the heart rate of the user , and they do so using a simple sensor usually located on the inside of the device.


Through the sensors that incorporate sports wrist accessories, our watch or wristband is able to detect our movement or measure our heart rate. Taking into account that these products are increasingly popular, and with the launch of the Samsung Gear Fit 2 in Spain so recent, this time we will tell you how sports wristbands are able to measure our heart rate .


To begin, we must put ourselves in context remembering that the heart rate meter is a component that is appearing more and more devices. While Samsung began to include it in its high-end terminals from the Galaxy S5  (today is not too popular in mobile phones ), it is the wrist accessories (wristbands, smart watches) that pay more attention to the heart rate sensors, which is justified with the orientation of these devices towards physical activity.


But how does the heart rate meter of our phone or wearable work? A sensor of this type are formed by a series of  photodiodes (sensors that emit light, neither more nor less)  that fulfill different functions. On the one hand there are diodes whose main function is to emit infrared light, while the other diodes will be responsible for receiving the light that is reflected.


What do we mean by the term “reflected light”? As you know, the heart rate meter should be placed near our skin. This short distance between the sensor and our skin makes it possible for light to be able to reach the veins. Once the sensor starts up, the light  emits a back reflection that indicates to the bracelet the level of blood in that particular place .


By pumping our heart blood several tens of times a minute, in each second the blood level of the Operation of a heart rate sensorparticular area we are measuring varies. And so, heartbeat after heartbeat, the processor of our watch or bracelet is able to determine the beats per minute of our body.


The very pumping of our heart’s blood causes the reflected light to vary at every moment. These changes allow our device to make an estimated measurement of our beats per minute, all with a fairly acceptable level of accuracy.


It is not nearly as accurate as a hospital machine , but for sports sessions there is no better tool available to any user. And to make it work even better, tips such as taking the wristband as tight as possible to the wrist , not placing the sensor on tattoos ( what Apple had headaches with this issue ) or cleaning the sensor are often essential to get results closest to reality.


From the operation of diode pulse meters some developers have created applications that measure the pulsations with our mobile, even if the phone does not have the necessary component. To achieve this, they use the LED flash of the camera as a light emitter , while the camera acts as a receiver of the same.


Measuring the pulse from the mobile is more thought for occasional use; If you want precision and constant registration, the sports bracelet is the ideal product


The applications to measure the heart rate with our mobile make us place the finger on the camera; from there, they activate the LED Flash and start measuring. Incredible as it may seem, these applications achieve a fairly acceptable accuracy (within what fits).


At the time I write these lines, I checked my heart rate with the Huawei Watch in one hand and the Nexus 6 in the other , there being a margin of error of one beat per minute in my results. If you are curious to discover the reliability of these measurements, and if you also have a watch with a pulse meter, you can try these applications on your own smartphone.