An advanced smartwatch that helps you tune in to your body, the Fitbit Sense is built to guide you toward better health with sleep and fitness tracking, an ECG app, SpO2 and stress management. Track your time in light, deep and REM sleep; use Smart Wake alarm to wake up during the optimal stage of sleep Use built-in GPS during runs, hikes, rides and other outdoor workouts to see pace and distance—without your phone After outdoor workouts, see a workout intensity map in the app that shows your heart rate changes along your route With a compatible ECG app right on your wrist, assess your heart for atrial fibrillation (Afib) a heart rhythm irregularity—and easily share results with your doctor The Fitbit ECG app is only available in select countries, pending applicable regulatory clearances; not intended for use by people under 22 years old Tracks SpO2—the level of oxygen in your blood—to help you learn when there may be an indication of changes to your wellness EDA Scan app detects electrodermal activity which may indicate response to stress; Fitbit app tracks stress trends and helps you reflect on your mood and try mindfulness tools Stay informed with heart rate notifications when Sense detects that your heart rate is above or below your threshold On-wrist temperature sensor tracks your skin temperature each night so you can see how it varies Water resistant to 50 m so you can wear it in the pool, shower and beyond Includes a 6-month free trial of personalized guidance and advanced insights from Fitbit Premium for new users Free trial is for new Premium users; must be activated within 60 days of device activation; valid payment method required; cancel before trial ends to avoid subscription fees Use your voice with Google Assistant or Amazon Alexa Built-in to check the weather, set reminders, control smart home appliances and more Battery lasts 6+ days—plus, fast charging gives you a full day's charge in just 12 min. (varies with use and other factors; up to 12 hrs. with continuous GPS)