9 to 5 Mac, the tip sheet for all things Apple, tracked down a patent granted to Apple (via Patently Apple) for computing health measurements using the iPhone. According to Apple in the patent, “electrical measurements may be used to measure heart function, compute an electrocardiogram, compute a galvanic skin response that may be indicative of emotional state and/or other physiological condition, and/or compute other health data such as body fat, or blood pressure.” It would use the front-facing camera, light sensor and proximity sensor to emit light that would be reflected back to the sensors. Additional sensors mounted in the same area would also generate additional health measurements such as body fat and EKG, which is already measured by the Kardia Mobile/Alivecor attachment. The camera and light sensor alone, based on the patent and the article, would measure oxygen saturation, pulse rate, perfusion index and a photoplethysmogram (which can monitor breathing rate and detect circulatory conditions like hypovolemia). Another demonstration of Apple’s keen interest in the health field, but what features will show up on real phones and apps–and when?