The Fitbit Sense is an advanced smartwatch designed for health and fitness tracking, focusing on stress management, heart health, and sleep quality. Key features include an ECG app for atrial fibrillation assessment, all-day stress tracking with a daily score, detailed sleep tracking with a personalized profile, and built-in GPS for workouts. It also includes notifications, a long battery life, and a user-friendly interface with features like Fitbit Pay, Amazon Alexa, and Google Wallet. 

• Heart Health: An ECG app is available for on-demand atrial fibrillation assessment, and the device can send irregular heart rhythm notifications. It also tracks your heart rate 24/7 and provides a Cardio Fitness Score.
• Stress Management: Tracks all-day body response, provides a daily stress management score, and includes mindfulness sessions to help manage stress.
• Sleep Tracking: Tracks sleep stages (light, deep, and REM) and provides a nightly Sleep Score and a personalized sleep profile.
• Workout Tracking: Features built-in GPS, automatic exercise tracking for over 40 exercise modes, and a Daily Readiness Score to help you optimize your workouts.
• Other Health Metrics: Tracks skin temperature variations, SpO2 (blood oxygen) saturation, and menstrual health cycles.