Polar a370 is a sleek and sporty water resistant fitness tracker that helps you stay on the pulse 247 with continuous heart rate monitoring advanced sleep tracking and polars unique workout features get to know your heart learn how your heart behaves in the twists and turns of your everyday life polar a370s wrist based heart rate monitor tracks your heart rate 247 so youll get a complete overview of your daily activity polar a370 shows you how many calories youve burned reveals your