A new app from the Rock Health accelerator program is called Cardiio and its an app that turns your device's camera into a biosensor to measure your heart rate by measuring light reflected off your face. Here's how they explain it:

“Every time your heart beats, more blood is pumped into your face. This slight increase in blood volume causes more light to be absorbed, and hence less light is reflected from your face. Using sophisticated software, your iPhone’s front camera can track these tiny changes in reflected light that are not visible to the human eye and calculate your heart beat!”

The technology was developed by spouses Yukkee and Ming-Zher Poh at MIT’s Media Lab. You can view your heart rate on a daily, weekly and monthly graph and users can see how their heart rate compares to others' and view potential life expectancy.

The app is available for $4.99 in the App Store for both iPhone and iPad.