I’ve recently seen a spate of reports of individuals whose “life has been saved” by the Apple Watch. Reading these articles generally reveals that it was actually the onset of atrial fibrillation that was detected. While that is very important and promptly addressing atrial fibrillation can allow treatment to prevent devastating strokes, I have yet to see true evidence of saving lives. Until they build in a defibrillator, I suspect most of the health benefits from this type of remote monitoring will be identification of bradycardia, atrial fibrillation and other cardiac arrhythmias. A large study on the value of arrhythmia monitoring with the watch, The Apple Heart Study, has had its rationale and design published but the results remain to be reported. Versions 4 and 5 of the Apple Watch can take a single lead EKG, but I have not seen any reports where changing morphology is used to detect hyperkalemia or QT prolongation or ischemia. There is a paper in preprint on using the Apple Watch to take standard and precordial leads, by placing it on the leg or changing the finger used to record. It remains to be seen if this rather cumbersome approach has practical utility in a busy medical practice.

So far glucose monitoring is not available, although there are monitors available that can be read on the watch. There have been rumors that a future watch will include noninvasive glucose monitoring, but Apple wisely does not comment on products in development. If such a feature is eventually launched, one could predict it would be of value in our elderly patients. 

Another health application of the watch is fall detection. Again, series 4 and 5 watches have an accelerometer and other sensors that combine to be able to detect falls. After a fall you can initiate a call to emergency services or dismiss the alert. It can call emergency services from almost anywhere in the world. If you are unresponsive after 60 seconds, the emergency call is placed automatically. Emergency contacts are then notified and sent the location. This feature is automatically turned on if you indicate during the watch set up that you are age 65 or older. It can be manually turned on at any age. I could not find any papers reporting on the clinical utility of this fall detection feature although I can think of situations for community dwelling patients where it has great potential value. 

Additional features that have potential health benefits include step tracking, which is quite accurate when compared to manual count from video recordings at a variety of walking speeds. This can be used to track activity and allow monitoring of walking as an exercise. There is also location tracking (“Find My”) available to share with friends or family. This can be useful in alleviating anxiety for distant concerned family members. 

So far, I haven't found watch apps or complications that are specifically medical. Of course, I love clicking on a complication to read my email on my watch, but likely the only medical implication is to worsen my eyesight. Overall, I think wearable technology like the Apple Watch shows lots of promise for medical utility, but as of now there is not much hard evidence that the current devices and software have enough medical utility to support us recommending them to our patients. The technology is still very young, and I look forward to seeing what the future developments bring.