HRV training at its best. Nice work from an Italian app studio. I have a passion for HRV monitoring and training to improve performance. Ive tested multiple apps, pc programs, and sensors, and this is a great monitor and trainer. Im happy to rate it 5-stars. Would love to see BluetoothSmart sensor integration in the next release. You can easily spend much more money for technology of this quality. Try 5-10 minutes of training every day for 6-weeks. One of the best counter-stress techniques that I know.