Tech Tips: Why does the green light keep burning in the smartwatch? The secret has been revealed, you will also be shocked after reading it

Nowadays, many features like smartphones are also available in smartwatches. Smartwatch can be operated from calling to messaging. Therefore, nowadays people prefer to buy smartwatches instead of buying common watches. If you are also a smartwatch user, then you must have noticed that when you remove the smartwatch from your wrist, a green light lights up for a few seconds on the back of the smartwatch.

Be it Apple’s expensive smartwatch or the smartwatch available in the budget-friendly segment, green light is used in every smartwatch. But now the question is, why green light is used in budget-friendly smartwatches as well as in expensive smartwatches worth thousands of rupees? There is a scientific reason behind this. Let us now know about it in details.

This is how a smartwatch measures the user’s pulse.
The simple answer is that it is easy to detect the pulse with the help of green light. Actually, the science behind it is very complex. Smartwatches use a process called photoplethysmography to measure pulse. This technology measures the amount of blood in tissue and skin. As blood reaches the skin and other body parts, capillaries expand and contract with the heartbeat. During this process, the smartwatch shines light onto the skin and records how much light is reflected back. This number then appears on the screen in readable format.

What does the green light actually do?
Blood contains hemoglobin, which turns red when it comes in contact with oxygen. It absorbs maximum light and reflects light of a specific wavelength. Anything red absorbs green light completely. That is why when a capillary is filled with blood, it completely absorbs green light. This makes it easier for the smartwatch to track when the capillary is full of blood and when it is empty. Additionally, green light cannot penetrate the skin as deeply as light of other colors. Therefore, the smartwatch takes readings from the body surface and records accurate measurements.

How are other colors of light used?
It’s not just smartwatches that use green light. Along with green, the company also uses other colors of light to measure other things. The smartwatch uses red light to measure blood oxygen. This measurement is based on a completely different process. Therefore, green light is not used in it.