The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Brendan Kennedy:
Do you workout with interval training? Is keeping track of your intervals during your workout more difficult than the workout itself? No matter what your fitness level, Heart Rate Trainer is for you. Heart Rate Trainer allows you to easily ADD, EDIT and PLAYBACK your interval training workouts. In the app you can define warm up, workout and cool down intervals. For each interval you can specify your target heart rates and their duration. During playback you can see your intervals rendered in elapsed or remaining time.