The Day the Apple Watch Stopped My Heart

Well, not literally. But when my Apple Watch told me my heart rate had dropped 60 beats in just a few seconds, my heart more than skipped a beat.

Due to a small heart-health scare this past spring I now exercise regularly. The Apple Watch has become a key ally in that still relatively new routine. Typically that routine is either a brisk outdoor walk or spending some time on a elliptical machine in our apartment. If it is an outdoor walk I’ll walk a leisurely mile to a local park and then cue up a 30-minute or longer workout using the Apple Watch’s Workout app. I’ll glance at a notification if it comes in during the walk, but typically I don’t pay much attention to the Apple Watch along the way, letting the haptic feedback tell me when I’ve gone half-way or completed the workout.

Almost two weeks ago a notification came in while I was in the early stages of a brisk outdoor walk and after dismissing the notification I noticed that my heart rate was about 100 or so. That seemed normal as I was heading to my regular rate of around 120/130. Just then another notification came in. After dismissing it, I noticed that my heart rate had dropped within just a few seconds to 41. Yikes!

Before coming to a sudden stop in a panic, my walking pace had not changed substantially, certainly not enough to warrant such a precipitous drop in my heart rate. Whether it was from sheer panic or just the Apple Watch recovering from a momentary glitch, my heart rate jumped back up into the 120 range in short order. My blood pressure levels however did not calm down for quite some time.

Regardless of why, this momentary drop of 60 or so beats a minute was more than enough to set me on edge. You can take a look at how your Apple Watch tracks your heart data in Apple’s Health app. If you’re using the Workout app you can see when and with what frequency changes occur. You can also see how and when the Apple Watch measures your heart rate throughout the day when you are not using the Exercise app.

Examining that data, the drop was indeed sudden. Further examination of data told me that there were other days during other exercise sessions when this sort of severe fluctuation occurred, but with no discernible consistency.

Needless to say I checked with my cardiologist. I had just seen him the week prior to this incident and based on tests during that visit he believes the watch’s systems are at fault, not mine.

I’ve since tried to recreate the situation but can not duplicate such a wide swing. Looking back over the data I notice drops and spikes from the 130 range to a range in the 60’s with some frequency but not with any consistency. My typical resting heart rate is in the mid-60’s. About once a day or so, typically when not exercising and for no discernible reason, there will be a recorded level in the 40's. (Intriguingly, the photo at the top of this post was snapped this morning while editing.)

Whether hardware or software, there’s a glitch. My doctor and I are reasonably sure it isn’t a physiological glitch. If it is a hardware glitch it would be pretty disappointing to see that kind of failure six months into the life of the device. If software I would hope it could be corrected via an update.

After discussing this with Apple the only way to further diagnose the issue is to send the watch away for testing, which I’ll do in a day or so.