A:
Garmin Activity Trackers like the vívosmart have sensors that are designed to detect natural repetitive walking motion as steps and calculate sleep, distance and calorie data.
Within Garmin's line of vívo activity tracking products, (which included the vívosmart, vívofit, vívofit 2, and the vívoactive) only the vívoactive is GPS enabled for running, biking and golfing features.
Thanks for asking! *CG