You may occasionally notice that your Apple Watch emits a green light from its back. This may be alarming if you’re a new user, but there’s really no need to worry — it’s all part of the watch’s design.
Apple Watch uses green LED lights and light-sensitive photodiodes to detect blood flow. The technology helps to measure and calculate the user’s precise heart rate. You can turn off this feature by going to Settings > Privacy > Health > Heart Rate > and toggling it off.
The green light on your watch’s underside is normal. But if you prefer, you can turn it off in your settings. Let’s take a closer look at what the green light does, how to turn it off, and also what other colored lights on your watch mean.
What Does the Green Light on the Apple Watch Mean?
The green light on your Apple Watch is normally for health-monitoring purposes and, at times, it comes on when using the Find My app.
When Exercising
A green light normally means your watch is trying to measure your heart rate. Your watch does so using the optical sensors found at its back. The data calculated is stored on your watch.
You’ll notice that the watch will light up during physical exercises. It will track your heart rate and update you on the screen. Such exercises include dancing, cycling, running, and HIIT.
Using Find My App
Another scenario in which the light may come on is when you use the Find My app to try and locate your Apple Watch. Your watch will produce a pinging sound in the process. In addition, its back will light green to help you locate it.
You cannot disable the green light in this scenario.
How Does Your Watch Read Your Heartbeat?
Apple uses advanced technology (photoplethysmography) for this process. The optical heart sensor will light up when it’s in contact with your skin and detects blood.
Naturally, blood reflects red light and absorbs green. That’s why Apple Watch uses green light to detect blood flow through the wrist.
How to Turn Off the Green Lights on an Apple Watch
Most users will prefer to keep the green lights functioning, since they’re part of an incredible feature that monitors your heart rate and alerts you in case of a problem. This information can also be useful to your medical professional when diagnosing you.
Even so, Apple has provided you with the option of disabling the feature if you find it a nuisance.
One option is to manually end your workout when you’re done, which will disable the light. After a workout, swipe right on your watch’s screen and tap End Workout.
You can also disable the feature permanently. When you do so, your watch won’t measure your heart rating during a physical session.
Let’s take a look at how to disable the lights directly from your watch and from your iPhone.
Using Your Watch
Here’s how to permanently disable the green light using your watch:
- Go to Settings.
- Select Privacy.
- Tap Health.
- Choose Heart Rate.
- Disable the option to track your heart rate.
Using Your iPhone
If you don’t have access to your watch, you can also disable the feature using your iPhone. Here’s how to do it:
- Open the Watch App.
- Go to the My Watch tab and select Privacy.
- Tap Heart Rate.
- Disable the permission.
Reverse this process if you want to turn it back on.
What Do the Red Lights on the Apple Watch Mean?
Aside from the green light, new Apple Watch models — from the Apple Watch Series 6 (on Amazon) and up — also feature a red flashing light on their backs.
Like the green light, this one is also for health purposes. The red light measures your oxygen levels in the blood. It indicates how well your lungs provide oxygen to the blood.
You can disable the red-light feature if you don’t find it useful. There are two ways to do it.
Using Your Watch
- Go to Settings.
- Tap the Blood Oxygen menu.
- Disable Blood Oxygen Measurements.
Using Your iPhone
You can also disable the feature using your iPhone:
- Open the Watch App.
- Select Blood Oxygen.
- Disable Blood Oxygen Measurements.
The Final Word
In summary, the green light on your watch measures your heart rate, while the red light checks for oxygen in your blood. Neither of these lights poses any danger or causes harm to your health. On the contrary, they are excellent features to help you keep your health in check.
We’re confident that we’ve answered all your questions on the topic. Feel free to reach out if anything is still bugging you. You can also read our article How to Ping Your Apple Watch From Your Phone and Vice Versa to learn how the pinging feature works.