Thanks. Been thinking about getting one, just to track sleep. But I'm not convinced if Fitbit is better than the sleep apps that don't rely on heart rate. Did you go with Fitbit because you were not satisfied with the apps that don't rely on heart rate monitoring? Or did you just happen to already have Fitbit?“Fitbit estimates your sleep stages using a combination of your movement and heart-rate patterns. When you haven’t moved for about an hour, your tracker or watch assumes that you’re asleep. Additional data—such as the length of time your movements are indicative of sleep behavior (such as rolling over, etc.)—help confirm that you’re asleep. While you’re sleeping, your device tracks the beat-to-beat changes in your heart rate, known as heart rate variability (HRV), which fluctuate as you transition between light sleep, deep sleep, and REM sleep stages. When you sync your device in the morning, we use your movement and heart rate patterns to estimate your sleep cycles from the previous night. “