Which heart rate monitor should you get

The HRV Health apps only work with H9 and H10 Polar heart rate monitors: which one should you get?

The Polar H9 and H10 heart rate monitors are the only commercially available consumer devices that provide data that is accurate enough to measure heart rate variability. 

The H10 costs is almost 50% more than the H9, so are the additional features worth the additional price. There are four features that differentiate the H9 from the H10:

  • The H10 can connect to two devices simultaneously, the H9 only one;
  • The H10 has the Pro strap, with a larger connecting surface area;
  • The H10 has an accelerometer;
  • The H10 can record an activity without being linked to your iOS or Android device;
  • The H10 records ECG readings, the H9 does not.

If you use the HRM exclusively for measuring HRV with the HRV Health app, then getting the H9 is fine. If you want to use the HRV Health’s new ECG functionality you will need the H10. 

We will use the accelerometer feature in future releases of the app, but only to check that user movement has not compromised the integrity of the data. Our recommendation: get the Polar H9 if you only require HRV readings. If you wish to do ECG readings as well, get the H10.


  1. The heart rate monitor is ON while connected to the strap and should always be removed from the strap after use.
  2. The heart rate monitor must be worn the right way up. Wearing the device upside down will produce incorrect results, for both the HRv and the ECG readings.

We have recently become aware of a problem with the Polar H10 heart rate monitor. When the battery level is low, the HRV metrics are wrong, and produce results are similar to those of when a person is suffering from a heart condition. We recommend that if you obtain unusually high RMSSD figures, you check the status of your battery using the Polar Beat app. If the battery is low, replace the battery, and take another reading.

This issue can also occur when the Polar strap becomes defective. Polar advises that the strap be washed after, and that the sensors are moistened before use. When the strap becomes defective, these washing the strap and moinstening the sensors makes not difference and the problem can only be resolved by replacing the strap. 

We have reported these issues to Polar, and they are looking into them.