Accuracy of Apple Watch series 8

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Level 1

4 points

Accuracy of Apple Watch series 8

Has anyone else discovered errors in the monitoring of aFib and the Apple watch seemingly inaccurate readings?

I have an Apple Watch series 8 and use it among other things to provide feedback on health issues. For the last 3 months the data has been showing that it estimates I am in aFib 35% of the time or more, which is unusual for me.

After visiting my cardiologist and going through a 2 week monitoring by a medical grade device, there was no similar readings, while my watch continued its estimates.

Posted on Nov 24, 2025 10:12 AM

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Answer 1

Nov 24, 2025 1:12 PM in response to dodgerms

Have you tried any troubleshooting? I'd start by unpairing and re-pairing the watch.

See also:

Get the most accurate measurements using your Apple Watch - Apple Support

As far as I can tell, I'm not getting inaccurate readings for aFib. It has never showed that I'm in aFib which could mean that I am but it's not recognizing it. I'm assuming it's correct as I've never had any symptoms and no doctor has picked anything up.

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Answer 2

dodgerms Author

Level 1

4 points

Nov 24, 2025 8:00 PM in response to IdrisSeabright

thank you so much for your reply to my request about my Series 8 watch.

I have gone through the link you provided in its entirety, and I receive what is apparently all good information daily. ( I have been wearing this watch for likely two years without hiccups).

I also went through the 7 items listed as well as the link regarding calibration. All those issues are not issues with this watch, other than the unusual aFib readings.

At this point and without any comments from others, including any monitoring reply from Apple, I am thinking something is defective in the sensor. I suppose my next step would be to send the watch to Apple for investigation and repair. It is out of warranty at this point in its life.

Again, thanks for your interest and input.

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