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What is the green light in Apple Watch? How to disable it?

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  • 3 min read

Your Apple Watch is packed with sensors to monitor health data, all hidden behind a sharp screen that ensures you have all the information you need available at a glance. All these sensors have different ways of gathering data which means you might see some weird lights flashing from your watch from time to time. 

In this article, we’re talking about the mysterious green light you can see flashing under your Apple Watch from time to time, what it actually does and how you can disable it if you so desire. 

Also read: Walkie-talkie in Apple Watch not working: Quick Fix

Apple Watch’s green lights explained

The green light flashing on the back of your Apple Watch is there for a functional reason. You see, Apple Watches (and just about every other smartwatch on the planet) are equipped with heart rate sensors which use green LED lights and light-sensitive photodiodes to determine the wearer’s heart rate. 

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Why green lights you ask?

Because human blood reflects red light and absorbs green. By rapidly flashing green LED lights on your wrist and measuring how much of it gets absorbed, the watch can count your heartbeats per minute. However, this only works when the watch is actively measuring your heart rate during workouts, to calculate your HRV and Breath sessions. The rest of the time the watch uses infrared light to keep track of your heartbeat which the human eye can’t see. 

How to disable the green light?

While we don’t recommend it, you can disable the green flashing lights on your Apple watch. Just follow these steps. 

  • Open the Settings app on your Apple Watch and tap Privacy & Security.
  • Scroll down and tap Health.
  • Tap the Heart Rate option.
  • Tap the Heart Rate toggle to disable green lights. 

And that’s all you need to do to disable the green flashing lights. Do keep in mind that while your Apple Watch will still measure your heartbeat, active measurements might be a little inaccurate. 

Also read: What is the difference between 40mm vs 44mm Apple Watch?


Yadullah Abidi

Yadullah is a Computer Science graduate who writes/edits/shoots/codes all things cybersecurity, gaming, and tech hardware. When he's not, he streams himself racing virtual cars. He's been writing and reporting on tech and cybersecurity with websites like Candid.Technology and MakeUseOf since 2018. You can contact him here: [email protected].