Fitbit Charge 4 Health & Fitness Tracker Awake or asleep.
- Built-in GPS, the Charge 4 lets you see your pace and distance when exercising outside
- It tracks runs, rides, and hikes.
- Charge 4 is capable of much more than that.
- Working hand-in-hand with your fitness tracking is the built-in 24/7 heart rate monitor, which can track calorie burn and let you know when you're in personalized heart rate zones. Based on your age and resting heart rate, it can tell you when you're in the fat burning, cardio, or peak heart rate zones.