Marco Altini, PhD on X: "Here is some heart rate variability (HRV) data collected using Garmin's Fenix 7, which offers an HRV spot check TLDR: Well, do not rely on this device
Garmin Previews HRV Status on the Fenix 6 Series Watches | DC Rainmaker
HRV Analysis | Garmin Connect IQ
Garmin fēnix® 7 – Standard Edition | Multisport GPS-smartwatch
How to use the HRV status feature on your Garmin watch | Tom's Guide