It's difficult to keep up the App Store these days as there are just so many cool apps to talk about. However, this one demanded some attention. It's a heart rate monitor and it uses the iPhone's built-in microphone to detect your heart beat.

 
This is one of those cases where something so simple is really pretty smart. All you have to do is hold your iPhone to your chest or under your jaw with the headphone microphone. The iPhone app then "listens" to your heartbeat and takes a measurement of it.

This is a great idea for those that have a goal heart rate or wish to keep track of it while on the go. This is also a good thing to have for pregnant women, who need to keep their heart rate under a certain level when exercising.

[via Ubergizmo]