The first heart rate monitor which makes use of Bluetooth is being developed by Dayton Industrial. This is a low energy heart-rate chest belt which employs the Nordic µBlue nRF8001 Bluetooth 4.0 chip and promises to be a forerunner of more such smartphone-based health and fitness monitoring apps.
It is possible to pair this device with any Bluetooth 4.0 equipped smartphone. The low energy heart-rate belt is designed to run for up to 1.5 years if used for about one hour per day from a CR2032 coin cell.
Source-Medindia