Why is my watch vibrating with a heart rate alert?

The Amazfit Cheetah 2 Pro triggers a vibration alert if it detects that your heart rate has remained above or below a specific limit for 10 minutes while you are in a resting state. This safety feature is designed to monitor for unusual cardiovascular changes when you are not exercising. You can customize these high and low heart rate thresholds or disable the alerts entirely in the 'Health Monitor' section of the Zepp app.