How does the 3 zone lights work on the Sensr 4.0?

The Sensr 4.0 will blink blue if a user’s heart rate is 119 BPM or lower. The Sensr 4.0 will blink green if a user’s heart rate is 120-179 BPM. The Sensr 4.0 will blink red if a user’s heart rate is 180 BPM or higher.