Is it possible you're talking about blood oxygen saturation? http://www.cultofmac.com/320322/apple-watch-sensors-are-capable-of-measuring-blood-oxygen/ http://w

Is it possible you're talking about blood oxygen saturation? http://www.cultofmac.com/320322/apple-watch-sensors-are-capable-of-measuring-blood-oxygen/ http://www.cultofmac.com/320322/apple-watch-sensors-are-capa...