Every once in a while I run across an app that totally surprises me. When I first heard of this app my first thought was: "no way, it must be a gag app".
But when I tried Instant Heart Rate by Azumio for the first time I was totally amazed that it actually worked, and it was pretty accurate.
It's the kind of app you want to have on your iPhone, even if just for showing off to your friends.
As you can tell by the name, what this app does is read your heart rate. In order to measure your heart rate with this app you need to put your finger over the iPhone's camera. Instant heart rate turns on the camera's flash and measures your pulse by measuring the light that gets through your fingertip. This technique is apparently used by medical pulse oximeters.
It's useful to have handy in case you want to measure your pulse and obviously as a fun application to show your friends.
Pretty cool use of the iPhone, you must admit.