Get the power of continuous heart rate monitoring with Fitbit’s slimmest design yet. This sleek device tracks your heart rate all day, including during workouts, so you can accurately measure calorie burn and find the right workout intensity for your goals. It even compares your resting heart rate trends to your activity to show how exercise improves your health. With sleep stage tracking, you can effortlessly monitor your time spent in light, deep, and REM sleep for a better night’s rest. Plus, automatically track your steps, distance, calories burned, and active minutes with up to 7 days of battery life.