HRV Expert

Free tool

Chest-strap HRV test

Connect a chest strap, sit still for two minutes, and get your RMSSD and other HRV numbers worked out from the time between your heartbeats.

What you need

  • A chest strap that sends beat-to-beat (RR) intervals over Bluetooth, such as the Polar H10 or H9, Garmin HRM-Pro or Wahoo TICKR. Most watches and arm bands send heart rate only, which is not enough.
  • Chrome or Edge on a computer (Windows, Mac, ChromeOS or Linux) or on an Android phone, with Bluetooth switched on.
  • Safari, and every browser on iPhone and iPad, cannot connect to a strap. On an iPhone, try the Camera HRV test instead, or enter a number from your app in the HRV checker.
Recording length

Your browser shows a list of nearby straps. Pick yours. The test then waits 15 s for the reading to settle before it starts recording.

How to take a good reading

  1. Measure at the same time each day, ideally soon after waking, before coffee and exercise.
  2. Wet the strap's electrodes and wear it snug, just below the chest muscles.
  3. Sit or lie down and rest. The test waits 15 seconds for your heart rate to settle before it records.
  4. Breathe normally, keep still and do not talk until the recording ends.
  5. Close other apps that connect to the strap. Many straps talk to only one app or device at a time.

The test removes beats that look like missed or extra beats before working out your numbers. If too many are removed, it shows no result rather than a wrong one.

Read more

Everything is processed on your device. Your heartbeat data is never sent to a server. If you are signed in, you can choose to save the result to your readings; only then are the RMSSD, mean heart rate and time sent. Privacy