The only scientifically validated HRV application that does not require an external sensor. HRV4Training helps you optimize your goals and avoid overtraining by measuring heart rate variability and providing personalized information about your fitness. HRV4Training does not require a heart rate monitor, because you can accurately assess your HRV with the phone's camera. About compatibility with your phone: the application will immediately detect if your phone is compatible so you can always get a refund if it is not.
(4.3 and up)
Ice Cream Sandwich (4.0.3 - 4.0.4),Jelly Bean (4.1 - 4.3.1),KitKat (4.4 - 4.4.4),Lollipop (5.0 - 5.1.1),Marshmallow (6.0 - 6.0.1),Nougat (7.0 – 7.1.1),Oreo (8.0-8.1)