My heart rate monitor measures the heart rate through a chest strap and by touching sensors at the watch's face. I just thought that was a cool functionality for a sports watch and will be of good use to me when I exercise.
My Heart Rate Monitor
Since I dunno what it does 'coz I rarely see anyone with that gadget. It is just a cool gadget that does something cool. I decided to read up on it.
It turn out tracking your heart rate ensures that you are burning most calories when you are doing cardio exercise. To effectively do cardio exercises, your heart rate should be 50% to 60% of its maximum at warm up and 60% to 85% of its maximum when doing an exercise to be really burn fat and other calories.
Learn more by asking our friendly resources, Google.