Runware presents the Runalyzer, the first patented heart rate monitor made for iPhone, iPad and iPod Touch, compatible with all analog chest straps and integrated with several apps in the App Store.
heart rate monitor
iPhone and iPad apps tagged "heart rate monitor."
Heart Monitor Keeps Track of Your Beats
New Zealand-based developer Bluespark has come up with a very simple and great idea - a heart rate monitor for the iPhone.
The app works with the built-in microphone on the iPhone 3G (older versions have to use the headphone cable mic) to listen and detect heart beats.