When Does Apple Watch Read My HRV?

While you wear Apple Watch it is constantly monitoring your heart rate and other data. If you are still and relaxed for a while, it will take your HRV reading.

You can view the raw data on your iPhone by opening Apple Health, browsing to Heart > Heart Rate Variability, and tapping Show All Data, then you can drill even further to each day and see when readings where made (if you want you can keep drilling down to the individual readings and the “beat-to-beat” measurements)

Ideally wearing your Apple Watch overnight will ensure you have good readings for the morning, and your recommendation is accurate. Many people do this, and then just charge it for a while first thing in the morning when they are getting ready.

You can also force Apple Watch to take an HRV reading by using the Breath App - just 1 minute will be fine :)