Heart Rate Zones is a free Android app developed by HC Studios, falling under the Lifestyle category with a focus on Health & Fitness. The app allows users to input their threshold heart rate to calculate personalized heart rate training zones for various activities like road cycling, triathlon, running, and more. It offers 7 training zones, including Joe Friel training zones, catering to different exercise intensities.

To determine your threshold heart rate, the app provides two methods: a recommended 30-minute time trial where you monitor your heart rate, or a less accurate method of subtracting your age from 220 and calculating 85% of the result. Heart Rate Zones aims to help users optimize their training by providing tailored heart rate zones based on individual thresholds.