Awake or asleep, the Charge 4 Health & Fitness Tracker from Fitbit is designed to provide you with all-day health and fitness tracking. Featuring built-in GPS, the Charge 4 lets you see your pace and distance when exercising outside, along with a map of your workout.Alerts you with a buzz when you reach your target heart rate zones when exercising, and will celebrate when you earn extra zone minutes outside of working out.When exercising outdoors, the Fitbit app on the Charge 4 can show you the heart rate zones you reached throughout your entire route.