A smartwatch can already count steps, track a run and tell you when your heart rate looks unusual. Google now wants its Pixel Watch to do something far more consequential: recognize when its wearer may be in a breathing crisis and cannot call for help.

The new feature, called breathing emergency detection, is rolling out to the Pixel Watch 4 and newly announced Pixel Watch 5 in selected European markets. It is designed for rare but serious situations in which blood oxygen levels fall dangerously low, potentially after choking, severe pneumonia or an accidental drug overdose. If the wearer becomes unresponsive, the watch can automatically contact emergency services and alert chosen emergency contacts.

That is an ambitious promise, and one that puts Google’s wearable firmly into a different category from routine fitness tracking. The company is not positioning the Pixel Watch as a replacement for medical care or a diagnostic device. Instead, this is meant to solve a painfully simple problem: in a crisis, the person who needs help may be unable to ask for it.

Google says the system uses an AI-based algorithm that analyzes readings from the watch’s heart-rate sensor, motion sensors and barometer, or altitude sensor. The goal is to identify a severe, sustained oxygen-related event while separating it from everyday moments that could look superficially similar, such as sleeping quietly or sitting still.

The safeguards matter because an automatic emergency call is a high-stakes action. Before escalating, the Pixel Watch checks for a low-motion state and looks for rapid changes in altitude that might suggest another explanation. It also avoids triggering after the user has been asleep for more than 30 minutes, a deliberate limitation intended to reduce false alarms tied to sleep apnea. Google cautions that the feature may still not detect every emergency, and says it is not intended for people with pre-existing respiratory conditions or for diagnosing or treating a medical condition.

If the algorithm flags a possible emergency, the watch does not immediately dial emergency services. First, it produces a strong vibration and displays a full-screen alert. If there is no response, an audible warning begins along with a 30-second countdown. Only after the wearer does not dismiss that escalation will the connected phone or an LTE-enabled watch place an emergency call. An automated message tells the dispatcher that a breathing emergency was detected, that the wearer is unresponsive, and shares their location; configured emergency contacts can receive an alert as well.

It is a carefully staged design, and it reflects the uncomfortable trade-off behind nearly every health-and-safety feature on a wearable. A system that is too cautious could miss a moment when seconds count. One that is too aggressive could send emergency services to someone who simply fell asleep on the couch. Google says it worked with internal medicine physicians, cardiologists, anesthesiologists and emergency-care specialists, then tested the algorithm in supervised clinical settings and against hundreds of thousands of hours of real-world data.

The feature also continues a shift in smartwatch safety design from passive monitoring to active intervention. Health dashboards can be useful over weeks and months, but they do little for someone who has suddenly lost the ability to use their phone. Google’s existing Loss of Pulse Detection feature follows a similar philosophy, looking for signs of pulselessness and escalating to emergency help when the wearer does not respond. Breathing emergency detection extends that idea to a different kind of emergency: one where oxygen deprivation may precede a complete collapse.

For now, though, the most important limitation is geography. Google has launched breathing emergency detection in Austria, Denmark, France, Germany, Ireland, the Netherlands, Norway, Sweden, Switzerland and the UK, with support limited to Pixel Watch 4 and Pixel Watch 5 users in supported regions. The United States is not included at launch. Reporting around the announcement notes that the feature has not received FDA clearance, and Google says it is working to bring it to additional countries over time.