If you’re trying to hit a target heart rate while exercising, then you’ve probably entered the hell that is biosensor apps. I dislike a lot of these apps because they require some form of extra junk that need to be plugged into your phone and then strapped to your body.
The Cardiio app has a clever solution for this problem, though. It stares at your face.
The technique is actually quite simple and even brilliant. As your heart beats, your face fills with blood and, ever so slightly, changes the amount of light your face absorbs. As a result, the Cardiio app just looks at the light reflecting off your face and looks at how quickly it changes to determine your pulse. Apps that had you lay your finger across the camera lens use a similar technique, but this doesn’t require you to smudge fingerprints all over a lens.
The best part? You just need your iPhone’s camera. There are some tradeoffs. The iPhone camera is not spectacular, so to get the right measurements, you’ll need to be in a very well lit area.
But that’s easy to take care of, and hey, it beats having something strapped to your chest.
Cardiio [Official Site]