Apple released the first update for the Watch OS this week with the intention of introducing improvements to Siri and third-party apps and fixing security issues. However, Watch OS 1.0.1 has gravely affected the heart rate sensor for a number of users.
Watch owners took to the Internet to point out the problem, posting on MacRumors' message boards and Apple's support forums. According to posts, the heart rate monitor has been taking infrequent readings as opposed to the usual once-every-10-minutes schedule the watch used to follow as recorded by the iOS's Health app. Real-time tracking is enabled though during workout and exercise.
Sometimes an updated Watch would stick with its default; sometimes it would take an hour or so for the next heart rate reading. According to Apple's website, the default interval should still be every 10 minutes, as the update has not been particularly designed to tweak the frequency of heart rate readings.
Could the gaps in the intervals in heart rate readings be due to the Watch not being worn or the wearable being turned off? Users have clarified in the forum posts that the gaps they have experienced don't coincide with such.
Fortunately, the Watch still records heart rates in real time during workouts as it normally does and when Glance has been set up to manually check heart rates.
As the issue is fitness-related, it is likely that only users of the Apple Watch's fitness features will notice it. However, given that health and data form a big part of the wearable's marketing, it will be important for Apple to fix the issue at the soonest time possible.
Some users have said the problem may be due to a change Apple introduced in an effort to boost battery life by sacrificing the frequency of heart rate readings. Others countered that this can't be the case because for some users the heart rate readings don't update unless manually checked. Other users also reported inaccuracies in heart rate readings given usual stats from before.
Hard resetting the Watch, resetting it back to factory and re-installing the OS don't seem to help with the issue. Users can report this problem or others they might encounter due to the Watch OS 1.0.1 update by leaving Apple with a feedback.