There is an optical heart rate sensor beside the camera on the back.
A heart rate sensor on the back combines with movement tracking for fitness monitoring.
The Gear Live also has a heart rate sensor built into the back for fitness tracking and is waterproof.
"A heart rate sensor, for instance, is much better suited to the underside of your wrist where you would normally measure a pulse".
Maybe the phone has a temperature sensor, or a heart rate sensor, we could guess whether the user is tense... .. said Sung, talking to TechRadar.
The 360 has a heart rate sensor on the back, while steps and activity are counted by an accelerometer for fitness tracking.
The smartwatch has a built-in heart rate sensor, but instead of being an optical sensor it uses a capacitive one.
Expert view: The heart rate sensor doesn't add much, but the bright screen and comfortable fit make it a solid Android Wear watch.
It looks more like a traditional watch with a completely round 1.3in screen and has a heart rate sensor on the back, unlike its square brother.
It runs Samsung's Tizen software, which means Android apps are not compatible and has a 2in curved screen with a heart rate sensor on the back.
The workout app uses the heart rate sensor and the accelerometer to track walks, runs, cycling, rowing, stair stepping and elliptical workouts.
