Heart Relay: Watch HR to Bike

About

Heart Relay turns your Apple Watch into a Bluetooth chest strap. Your watch measures, your iPhone broadcasts, and your bike computer or training app sees a regular heart-rate sensor. After the ride, bring the FIT file back into Apple Health with route, heart rate, distance and calories. HOW IT WORKS Heart Relay advertises the standard Bluetooth Heart Rate Profile. Anything that accepts a chest strap will find it as "Heart Relay": Hammerhead Karoo, Wahoo ELEMNT, Garmin Edge, Zwift, Rouvy, MyWhoosh, Peloton, Concept2 and many more. The iPhone has no ANT+, Bluetooth is all you need. Once connected, lock the iPhone and put it away. The connection stays. HEART RATE FROM THE IPHONE (iOS 26) AirPods Pro 3 or a chest strap paired in iOS deliver heart rate straight to the iPhone, on their own or together with the watch. ZONES, ALERTS, VOICE • Five Karvonen zones from age and resting heart rate, pulled from Health if you like • Zone colour and zone hearts on iPhone and watch • Zone changes as haptic, tone or voice, set separately for watch and iPhone • Heart-rate announcements on change, on wrist raise or on double tap • Choose language and voice; music ducks briefly and comes back DURING THE RIDE • Start and stop from the iPhone or the watch • 13 activities, indoor or outdoor • Live Activity with heart rate, zone and elapsed time on the Lock Screen and in the Dynamic Island, with a stop button • Keep the workout in Health: ask, always or never FIT IMPORT INTO HEALTH Open the ride from your bike computer as a FIT file, share it to Heart Relay or drop it into the Files app. Heart Relay writes the workout, route, heart rate, distance, cadence, power, speed, laps and weather into Health. Calories come from the file, from power or from heart rate. Duplicate rides are detected. YOUR DATA STAYS YOURS No account, no cloud, no ads, no tracking. Heart Relay has no server. Everything happens between your watch, your iPhone and your bike computer. Try everything free for 7 days, then unlock once. No subscription. REQUIREMENTS iPhone with iOS 17 or later, Apple Watch with watchOS 10 or later, and a receiver that supports Bluetooth heart-rate sensors. AirPods Pro 3 and chest strap as a source need iOS 26. Questions or feedback: hello@tekneio.com