The migration from simple stop watches to working out with computers on our wrists began with heart rate, and even now, most of the data measured by Garmin's fleet of scary-smart gadgets has something to do with that metric. Access everything your new watch can do and learn how hard your heart works during different activities, whether you're working towards heart rate-based training or are just curious, with Garmin's HRM-Run. It pairs with the brand's newer devices and features an acclerometer to keep track of how fast you're moving inside or out on the roads. Whether you're barrel-chested or petite, the soft, stretchy strap will adjust to fit around your rib cage, and once you have it adjusted, the strap will stay out of your way while you work up a sweat.