HR Monitor Accuracy

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The following article is for watches with heart rate monitors, and doesn’t apply to Pebble Classic, Steel, Time, Time Steel or Time Round.

Note: if you haven’t set up Pebble Health yet, you’ll need to. Instructions can be found here.



Pebble HR watches feature an optical heart rate monitor, which we’ve tested against industry leaders, including wrist- and chest-based monitors. Please see below for specifics about our device’s accuracy, and for tips to get the best readings.

What affects accuracy? How you wear your watch is very important to accuracy (see “Wearing HR Watches” above), but other factors matter, too. For example:

  • Movement: extremely intense exercise can reduce accuracy due to excess movement
  • Watch straps: metal straps and those made of stiffer leather may not hold the monitor firmly in place, leading to poor readings.  Make sure your straps fits snugly!
  • Tattoos: dark tattoos may impair the optical monitor’s ability to read your heart rate
  • Water: while sweat or splashes of water aren’t a problem, optical heart rate monitors do not work underwater

Pebble devices with a heart rate (HR) monitor are intended to be a valuable tool that can provide an accurate estimation of the user’s heart rate. The HR monitor is designed to attempt to monitor a user’s heart rate on a periodic basis. The frequency at which heart rate is measured varies and depends on the level and activity of the user.

While the HR monitor technology is state of the art, there are inherent limitations of the technology that may cause some of the heart rate readings to be inaccurate under certain circumstances. These circumstances include the user’s physical characteristics, the fit of the device and the type and intensity of the activity. The HR monitor data is not intended to be used for medical purposes, nor is it intended to diagnose, treat, cure or prevent any disease or condition.

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