Google is using artificial intelligence (AI) to save lives, successfully implementing Loss of Pulse Detection in the Pixel Watch 3.
Initially announced in 2024 for the Pixel Watch 3 in the European Union, Google shared on Feb. 26, 2025, that it received clearance from the U.S. Food and Drug Administration (FDA) to implement the “first-of-its-kind feature” and begin its rollout in the United States at the end of March.
In a previous blog post, Google explained that a loss of pulse happens when the heart suddenly stops beating. The condition can affect people at any age and may be caused by various issues, including primary cardiac arrest, respiratory failure, circulatory failure, overdose, or poisoning.
When such a situation occurs, the watch automatically prompts a call to emergency services, potentially providing life-saving assistance.
“For three years, Pixel Watch has given people peace of mind with safety and health features like Car Crash Detection, Fall Detection, Irregular Heart Rhythm Notifications, and the ECG app and Safety Check,” Google said. “Loss of Pulse Detection is a great addition to these potentially life-saving tools.”
Here’s how it works: The opt-in feature combines signals from the Pixel Watch 3’s sensors, AI, and signal-processing algorithms, employing the watch’s Heart Rate sensor and green light to monitor a user’s pulse, per Google.
When signs of a loss of pulse are detected, infrared and red lights activate to gather additional pulse signals while the motion sensor checks for movement.
An AI-based algorithm integrates data from the pulse and movement sensors for confirmation, prompting a check-in on the watch to see if users respond.
During the check-in, the watch will ask if everything is OK while also monitoring for movement. If there is no response and no motion detected, the Watch 3 takes the situation to a higher level of alert by sounding an audio alarm and initiating a countdown.
If the countdown goes on without a response from the user, the LTE watch or the connected phone automatically contacts emergency services with a location and an automated message indicating pulselessness.
The blog post notes that Google partnered with stunt actors to simulate real-world loss of pulse events and validate that its technology works. The company also sought expert feedback and ideas, including emergency medical service providers, dispatchers, and paramedics.
“Our goal is to make a difference and contribute towards saving lives,” Google said. “While Loss of Pulse Detection won’t detect every loss of pulse event, we believe it can make a meaningful difference, providing help when it counts most to people and their loved ones.”
