What the Green Lights Do on Your Apple Watch + Ways to Disable Them

Why Your Apple Watch Has Flashing Green Lights

The green lights on your Apple Watch are the heart rate sensors. These lights periodically flash when you're wearing your Apple Watch to measure your heart rate. These lights can be disabled by turning off the watch's heart rate sensor. There's no way to keep the heart rate sensor on and also turn off the green lights. According to Apple, this is called "photoplethysmography," which works around the fact that blood is red and absorbs green light. The amount of blood flowing in your wrist increases and decreases with the beating of your heart. This also affects how much green light is absorbed from the sensors on the back of your Apple Watch, which is how it can measure your heart rate.

Disabling the Lights via Your Apple Watch

Press the Digital Crown and select the Settings app. The Settings app has a gray icon with gears on it.

Select Privacy & Security > Health. This will open privacy settings relating to what health metrics your watch can gather.

Toggle off heart rate. This will disable the green light sensors on the bottom of your Apple Watch.

Disabling the Lights via Your iPhone

Open the Watch app. The Apple Watch app has a dark gray icon with an image of an Apple Watch on it.

Select Privacy. You may have to scroll down to see this option.

Toggle off heart rate. This will disable the green light sensors on the bottom of your Apple Watch.

Fixing Green Lights That Constantly Flash

Check your Workout or Mindfulness app. You may have an active workout or breathing exercise going. If so, the green lights on your Apple Watch may flash due to your watch needing to check your heart rate more often. And as such, the green lights could continue to flash after you remove your watch. To end a workout or breathing exercise, open the corresponding app and swipe right, then tap the End button.