The app makes Apple Watch to vibrate when your current heart rate goes out of specified bounds. This is helpful when you are doing a fitness and don't want to look on your wrist for checking heart rate from time to time.

App retrieves heart rate information from Apple Watch sensor via the Health app.

Note: in the background, app works only for one hour due to system limitations. To use it during long training, you need to reopen it at least one time per hour.

This is app has the following functionality:
- Vibrate when your heart rate is out of specified bounds;
- Specify heart rate bounds on your own;
- Calculate optimal heart rate bounds by using the Karvonen Formula;
- Delay vibrating for 1-15 minutes from workout start.