A free app for Android, by Cardiogram Inc..
Cardiogram is the world’s best-selling wearable heart rate monitor app for the Apple Watch and other Wear OS watches. It is free to download and use, and you can also download the companion Cardiogram Wear OS app for your phone to get a heart rate reading from your phone.
Cardiogram provides you with a complete view of your heart rate and its trends over time. You can also see how many calories you burned in the last week, as well as track any other metrics you care about, such as blood pressure, oxygen saturation, and sleep quality.
Cardiogram also tracks your heart health in real-time, allowing you to see how it changes over time. You can use the app to view your heart rate in the last 24 hours, as well as see how many beats per minute you had last night. You can also use the app to view any trends or changes you’ve seen in the last day, week, month, or year.