Xiaomi introduced Mi Health app last year, and since then it has been the primary application to find all the health-related information the Mi devices are gathering - heart rate, steps, BMI, exercise goals, Health Scores, etc.
According to XDA-Developers, the v2.7.4 version of the app will now be able to actually measure your heart rate using nothing but the camera of your phone and no additional sensors or hardware.
The feature is rather simple to use - you put its index finger on the camera lens and wait until the progress bar gets to 100% (just don't forget to clean the lens after that or you'll get smudged photos). You should then select whether it was a General Status, Resting Stare, or was After Exercise. There will also be a Test report, revealing whether the heart rate is slow, normal, or fast.
Collected over time, the data will show in the app’s dashboard, easily allowing users to keep track of their heart rate. Sadly, this app is still not available on the Google Play store so you can only use it if you sideload the APK.
totall bs,let uncle Trump takes out Xiaomi too
Lots of apps on Play Store already do this. Xiaomi is just putting in their default app.