The person next to you
might need your help right now.
handsforhearts uses Apple Watch's continuous biometric monitoring to detect cardiac arrest, then broadcasts a Critical Alert to every nearby iPhone — turning strangers into lifesavers in under 90 seconds.
Three steps. One life saved.
From detection to CPR in under 90 seconds — all automated, all hands-free for the victim.
Apple Watch Detects
The Watch continuously monitors heart rate, HRV, SpO₂, and motion. An on-device ML model detects the combined signatures of cardiac arrest in real time.
Multi-signal consensus: HR drop + zero motion + SpO₂ decline
Critical Alert Fires
The victim's iPhone broadcasts a Critical Alert via APNs to every opted-in device within 100 meters. It bypasses Do Not Disturb and Silent mode. 911 is called simultaneously.
Reaches all opted-in iPhones nearby — no internet required as fallback
You Respond
Tap the alert to open a live map with the victim's exact location updating every 2 seconds. See how many others are responding, and access guided CPR instructions instantly.
GPS live-tracking · responder count · guided CPR · 911 coordination
A 10-second cancellation window prevents false alerts. Multiple sensor signals must confirm before broadcasting.
See it happen in real time.
This is exactly what appears on a bystander's screen during a cardiac emergency.
Passive protection, always on.
Your phone sits in your pocket, completely normal. handsforhearts runs silently in the background, location shared only when an emergency is active.
No battery drain. No constant notifications. Until they matter.
Every second counts.
Cardiac arrest is survivable. The window is narrow. The gap between life and death is usually measured in minutes — and whether a stranger knew what to do.
What happens in the minutes after cardiac arrest
handsforhearts targets bystander response under 90 seconds — well within the survivable window.
Be ready when
it matters most.
The app is in development. Learn CPR now so you're ready the moment a life is on the line.
handsforhearts is a supplementary tool. Always call 911 in an emergency. CPR guidance follows American Heart Association guidelines.