A free program for Android, by Yingding Wang.
Stila is the first Wear OS and Fitbit smartwatch/ fitness tracker app that not only tracks your heart rate but also shows you your stress level based on the data measured. The app determines your stress level by analyzing the heart rate patterns, and it can also track changes in your environment (e.g. by switching on a different mode, like walking, running, or cycling).
It works as follows: First, you need to buy a wearable device that can measure your heart rate (e. a wearable fitness tracker like a Polar H7 heart rate sensor, a Garmin Active HR, or a Wahoo Tickr T3 heart rate tracker). You also need to install the Stila app. When you wear the device and start the app, it will ask you to complete a quick survey. This survey consists of two parts.