After installing the recent Watch OS update 1.0.1, a number of Apple Watch owners have found that the device’s heart rate monitor has stopped working. Under general use, the Apple Watch should monitor your heart rate when in the background, taking readings every 10 minutes to update the health app on the device. However, with the 1.0.1 update, the monitor may only work when directly instructed to do so, and when put in the background it will pause and stop taking readings.
While some users are noticing heart rate collection stopping in the background, others are noticing the readings are simply sporadic, where the device will pause for a while, and then collect a number of data points at once, followed by seemingly regular and expected 10-minute intervals, and then more sporadic behavior.
This problem will likely affect your ability to use the heart rate monitor as a reliable health metric, and unfortunately there is little that you can do to fix or overcome it. Restarting and otherwise resetting the device does not seem to affect this problem, so the only option for affected users is to use the monitor in the foreground.
This issue will require a software patch in order to fix, so if you are affected then you will have to give Apple’s engineers time to address it. Alternatively, if you have not yet updated to Watch OS 1.0.1, then consider avoiding the update for now, especially if you use the heart rate monitor. As with other Apple devices, there does not appear to be a way to downgrade the Apple Watch to a prior version of its operating system software.
In the past when such immediate problems have become apparent, Apple has issued supplemental updates within a couple of days. We will have to wait and see when Apple will address this specific problem, but the fact that the Watch is a new and hot product for Apple right now means that affected users are in luck. Apple wants this product to be flawless, and for any problem will be interested in collecting samples and data to address it as soon as possible, so it should not be long before the heart rate monitor is working again.
Apple quality control muffs another one.