Apple Watch wearers may sometimes notice a green light on the back of the wearable device. While this is completely normal, it’s worth understanding why they’re there, what they do, and how to turn them off. The Apple Watch is still the best smartwatch for iPhone users, but it may take some time to get used to all the features. The use of green lights is one such example. The back of your Apple Watch periodically lights up with bright green lights, and if you’re not sure what they are, they can be quite alarming.
The green light on the Apple Watch seems ominous, especially considering it’s on the back of the device and will most likely go unnoticed by the wearer most of the time. The fact that the green light sometimes comes on even when the watch is not being worn adds to their mystique. Still, these lights are only used to measure people’s heart rates. Essentially, the Apple Watch uses these green LED lights to detect blood flow and then uses that to help determine the actual heart rate. Sometimes, when the watch takes more frequent heart rate measurements, the green LED light becomes more active.
How to turn off the green light on Apple Watch
There’s no real reason to turn off the green lights since they’re used to measure heart rate. However, sometimes the watch may make measurements unintentionally. For example, if the watch is not being worn but the green light is on, it may be because a workout is still in progress. During this time, Apple Watch will seek to monitor heart rate more frequently and cause the lights to activate more frequently. Simply stopping the exercise will also prevent the green light from activating.
If the user wants to completely disable the green light, the only option is to turn off the heart rate sensor completely. To do this, simply open your Apple Watch’s Settings app and navigate toprivacy,’ followed by ‘healthy.’ Here the user will find the click “heart rate‘ and disable the feature. Again, this will completely prevent the Apple Watch from taking measurements, and users will need to enable the feature (and the green light) if they want to measure heart rate again.
How to measure heart rate with green light
The Apple Watch uses green light to measure heart rate because blood absorbs green light. A green LED light is paired with a light-sensitive photodiode to detect the amount of blood flowing through the wearer’s wrist. A higher heart rate translates into more blood flow, which results in more green light absorption. Although it may not be obvious, the Apple Watch’s green light flashes hundreds of times per second, and the optical heart rate sensor can measure a user’s heart rate from 30-210 beats per minute.
Apple Watch’s optical heart rate sensor can also use infrared light to measure heart rate in the background and provide heart rate notifications. The green light, on the other hand, is used to measure the wearer’s heart rate during workouts and when using the Breathe app. In addition to heart rate, the Apple Watch can also capture an electrocardiogram, but this is done by placing your finger on the Digital Crown.
What is the red light on Apple Watch?
In addition to the green light, Apple Watch users will occasionally notice a red light on the back of the smartwatch. Like the green light, the red light also indicates another health tracking feature, in this case blood oxygen monitoring. Apple Watch Series 6 and later can measure the wearer’s blood oxygen (SpO2) level. The bright red light works similarly to the green light, using photodiodes to calculate oxygenation levels in the wearer’s blood.
If blood oxygen and background readings are enabled on Apple Watch, the wearer may notice a red light while in bed because measurements are calculated while sleeping. If this problem occurs, users can do this by opening the Settings app on Apple Watch and clicking “Turn off background measurements.”blood oxygen‘then close’sleep focus‘ and ‘in theater mode.’ Apple Watch users can take a manual blood oxygen reading at any time by opening the Blood Oxygen app and following the prompts.
Source: Apple