I'd love it if the first generation Apple Watch had an oximeter. But I don't think it will (despite all the sensors on the back). The reason is the FDA. Measuring your pulse rate is something that has been done for centuries if not millennia. But pulse oximetry is very recent, and the bureaucrats are willy waving to show that they're in charge. See e.g. this article that discusses the topic. http://mobihealthnews.com/29956/building-the-case-against-ap...