Google’s Pixel Watch 3 Loss of Pulse Detection Feature Receives FDA Clearance

The FDA granted clearance to Google’s Pixel Watch 3 for its Loss of Pulse Detection feature, which detects when the wearer has experienced a loss of pulse.¹ The first-of-its-kind feature, which was initially announced in August 2024², automatically prompts a call to emergency services for potentially life-saving care if the watch detects the wearer as unresponsive, according to Google.¹

Image credit: Renhue | stock.adobe.com

Loss of pulse is defined as the absence of a detectable pulse that usually results in loss of consciousness and requires urgent emergency intervention. This can occur from a variety of causes, including—but not limited to—cardiac arrest, respiratory or circulatory failure, overdose, or poisoning. When the heart beats, the blood volume in the user’s arm changes, and while wearing the watch, Loss of Pulse Detection uses optical heart rate sensors on the back of the device to detect the wearer’s heart rate.^2,3

If a pulse isn’t detected while wearing the Pixel Watch, it will vibrate and check in to see if the user needs assistance. If movement or a pulse is detected, the check-in is automatically dismissed; however, if nothing is detected after about 15 seconds, the watch will play a loud sound and begin a countdown. If the user does not need assistance, they are able to dismiss the countdown on the watch’s face. If a response is not provided during the countdown, the watch will attempt to place a call to emergency services, and if the call connects, the watch plays an automated message that shares the wearer’s location and informs the emergency call operator that a pulse wasn’t detected and no response was received.^2,3

This feature, according to Google, was developed with cardiologists and specialists to determine how a loss of pulses might manifest on the watch, and from there, artificial intelligence and digital signaling processing were used to detect the time-sensitive events. Loss of Pulse Detection was tested in a diverse group of people to assess its efficacy across different gender, ethnic, and racial groups.^2,3 Interestingly, Google reported that the development also included hired stunt actors who simulated real-world scenarios in which a person may lose their pulse. In these scenarios, the actors wore tourniquets to artificially induce pulselessness, then simulated the types of falls that mimicked a person who suddenly lost their pulse.⁴

“Loss of Pulse Detection is part of our broader effort to make Pixel Watch a guardian of your health and safety,” a representative from Google said in a news release. “It joins other features like Irregular Heart Rhythm Notifications, which can check for signs of atrial fibrillation; Safety Check, which allows you to set a timer on your device when you feel unsafe to then send your location to a loved one if you don’t respond; and Fall and Car Crash Detection, which can check in and call for help if you fall or are in an accident.”⁴

Although Loss of Pulse Detection serves as a safety tool, Google emphasized that the feature does not serve as a diagnosis, indicate the presence or lack of an underlying health issue, or suggest a need for medical care. Users should always talk to a health care professional about their health concerns.³

Currently, Google expects to roll out the Loss of Pulse Detection feature in the US at the end of March 2025; however, it is currently available on Google Pixel Watch 3 for users in 14 countries, including the UK, Ireland, France, and Italy, as well as others. Google noted on a webpage that additional countries will be added as regulatory clearances are obtained.³

REFERENCES

1. Google — The Keyword. Loss of Pulse Detection has received U.S. FDA clearance, and is now available on Pixel Watch 3. News release. February 26, 2025. Accessed March 3, 2025. https://blog.google/feed/pixel-watch-3-loss-of-pulse-detection-fda/

2. Google — The Keyword. Loss of Pulse Detection: A first-of-its-kind feature on Pixel Watch 3. News release. August 13, 2024. Accessed March 3, 2025. https://blog.google/products/pixel/pixel-watch-3-loss-of-pulse-detection/

3. Fitbit Help Center. Sleep and wellness: What is Loss of Pulse Detection on my Google Pixel Watch?. News release. Accessed March 3, 2025.

4. Cardiovascular Business. FDA clears Google smartwatch tech that calls 911 when a user’s heart stops. News release. February 27, 2025. Accessed March 3, 2025. https://cardiovascularbusiness.com/topics/clinical/heart-health/fda-clears-google-smartwatch-tech-calls-911-when-users-heart-stops