Optimize Apple Watch Heart Rate Readings

Have you see flatlines or choppy heart rate readings from your Apple Watch?


The most basic thing to check is to make sure you’ve enabled ALL your Apple Health permissions but if that hasn’t helped, or you have results that aren’t quite flat-lined for an entire workout, something like this: 


Here are some tips to get the best out of your experience and the cleanest heart rate readings we can get while tracking activities. Like most wrist based HRMs, the values are not quite as accurate as those of chest straps or the Scosche Rhythm+, but there are a few things you can do to help.

Tighten and check position of the Apple Watch

  • Check the positioning of your Apple Watch. The Watch should be snug, but still comfortable. You can move the Watch so it sits higher on your wrist (toward your elbow).

Close Apps Currently in the Background

  1. On the Watch, press and hold down the side button until the shutdown screen appears. Release the side button, then press and hold the Digital Crown to force quit the active app
  2. Force quite any other apps running on the iPhone as well

Restart Fitdigits app on Watch and iPhone – see Troubleshooting

In the end, a lot of factors play into results, but you should be able to be as fluid as the screen shot above!

Special notes:

  • Haptics will disrupt the optical heart rate sensor on your Apple Watch. When your Watch buzzes from notifications, it will not query HR for that moment, which can result in a brief dropout.
  • Like with other heart rate monitors, we recommend using one app at a time. Using Fitdigits along with the Heart Rate or Workout app will result in poor readings.

Happy tracking!

Apple Watch 

Installing the Companion App

Apple Watch Setup 

Optimize Heart Rate from the Apple Watch

Troubleshooting