The Pixel Watch 3 has been unveiled as Google’s new flagship wearable and has a surprise life-saving feature not seen before on any smartwatch .
Google is calling it ‘Loss of Pulse Detection’ and says it’s a “first-to-market smartwatch feature intended to detect pulselessness”. This could potentially save lives as the watch can call the emergency services when it detects an issue.
Half of loss of pulse events are unwitnessed, says Google, so the Pixel Watch 3 could make all the difference, especially when time is of the essence. The feature can detect a loss of pulse from cardiac arrest, poisoning and respiratory arrest.
How does it work?
Google says it works by using the Pixel Watch 3’s multi-path heart rate sensor (which many wearables have), along with an AI-based algorithm. When signs of pulselessness are detected, the smartwatch activates additional sensors to check for a pulse and movement.
“If no signs of pulse or motion are detected, it begins an initial check-in, escalating to an audio alarm and 20-second countdown.”
“Then, a call to emergency services is automatically placed on an LTE smartwatch or connected smartphone, sharing critical context with the operator, like GPS location and that the person is showing signs of pulselessness”, says the firm.
Can you trust it?
We’ve learned quickly that AI isn’t necessarily trustworthy but Google insists that the feature has been rigorously tested in lab and clinical conditions and the algorithm tested for hundreds of thousands of hours to reduce the risk of false detection.
Real-life patients in a cardiac electrophysiology lab also wore the Pixel Watch 3 as part of the testing. They underwent procedures requiring induced ventricular fibrillation, providing a real-world situation to test the algorithm on humans. It was also tested using a tourniquet.
Loss of Pulse Detection has received regulatory approval – but only in some markets. See below for the list of launch countries, which doesn’t include the USA where the FDA (Food and Drug Administration) has not cleared the feature.
- Austria
- Denmark
- France
- Ireland
- Netherlands
- Norway
- Sweden
- Switzerland
- United Kingdom
The Pixel Watch 3 goes on sale 10 September, starting at £349/$349.99.
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Author: Chris Martin, Managing Editor, Tech Advisor

Tech Advisor Managing Editor Chris got his break as a reporter at infamous site The Inquirer and has been with us for more than 12 years. With a BA degree in Music Technology, audio is his specialism, but over the years he has reviewed all kinds of gadgets, from smartwatches to mesh Wi-Fi to coffee machines.
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