How to measure HRV

Chest straps like the Polar H10 are the gold standard for HRV measurement. Wrist-based devices (e.g., Apple Watch) aren't perfect but are surprisingly decent for raw data — if you use them correctly.

Most dedicated HRV apps (HRV4Training, Elite HRV) are clunky. Apple Health has a good UI but collects HRV data randomly throughout the day, making it practically useless.

What we need is to take measurements at a consistent time each day, away from stressful moments, e.g., right after waking up.

The measurement protocol with Apple Watch:

1. Each morning, immediately after waking up, sit still and measure as follows:
2. Use the Mindfulness (fka Breath) app on Apple Watch - the breath exercise lets you manually trigger an HRV reading.
3. Use Athlytic, which can pull only these manually triggered measurements and ignore everything else from Apple Health.
   1. Confirm in its settings that this behavior is enabled (it's on by default) and ensure it has read access to the beat-by-beat measurements from the Apple Health app.
   2. For the HRV calculation method, switch to rMSSD instead of the default SDNN.

Ref: https://marcoaltini.substack.com/p/apple-watch-and-heart-rate-variability