The Polar A370 wrist tracker monitors activity, heart rate and calories burned throughout the day and sleep during the night. It also offers coaching and feedback on both workout and sleep performance, allowing wearers to understand how they can improve. Goal setting also means that if a user is inactive for too long, they’ll be given a soft reminder to raise their activity levels. The device also uses GPS to track pace and distance, and map routes. Plus, smart notifications help keep track of calls, messages, calendar and social media updates.