A free program for Android, by ANT.

ANT Heart Rate Grapher is a free graph-based app for displaying the data from a heart rate monitor. It can graph and show data from any type of ANT+ heart rate monitor, as long as it has an ANT+ radio. The app allows you to choose the type of graph you want to view: simple graph, line graph, or pie graph. You can add any number of data points to the graph, which makes it very easy to see changes in heart rate over time.

To use the app, you will need to install the ANT Heart Rate Grapher app from the Play Store. You will also need to connect your heart rate monitor to your phone. The app will then automatically start collecting the data from your device. If you want to stop collecting data, you can disable the automatic collection in the settings of the app.