The heart rate sensor on the back of the Apple Watch is very accurate, a recent report has shown, on par with some of the most accurate heart rate monitors that are currently available. Unfortunately, it looks like Apple may have inadvertently crippled the heart rate functionality with its most recent software update.

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Soon after the Apple Watch received its Watch OS 1.0.1 update, some users noticed that their devices weren’t writing heart rate data to the Health app on the iPhone as often as they should, complaining about their experience on forums including MacRumors and Apple’s own support pages.

The device records your heart rate during intense workouts, but also periodically throughout the day. The Watch is set to record the user’s heart rate every 10 minutes during the day and also while the user is asleep, if he or she wears the watch. Once the Workout app is turned on, however, the device records heart rate continuously, offering you constant feedback during training sessions.

Users are now complaining that following the recent Apple Watch software update, the device sometimes fails to write data to the Health app. Instead of 10 minute intervals for non-Workout activities, some users have seen gaps between readings of up to two hours.

Apple Watch heart rate readings in Health app: During workout (left) and during regular use (center and right)

Since getting the Watch, I have used it to better monitor my workouts, but I have not always paid attention to readings inside the Health app. However, I can say that after the Watch OS 1.0.1 update I can also spot gaps in heart rate recordings, as seen in the image above.

One reason for cutting down the frequency of heart rate readings during the day is to increase battery life. But Apple hasn’t updated its Watch pages or the Watch 1.0.1 change log with information pointing along those lines. The Watch should still take heart rate readings every 10 minutes.

Apple has not acknowledged the issue yet, but it’s likely that this heart rate bug will be fixed in a future update.

Chris Smith started writing about gadgets as a hobby, and before he knew it he was sharing his views on tech stuff with readers around the world. Whenever he's not writing about gadgets he miserably fails to stay away from them, although he desperately tries. But that's not necessarily a bad thing.