Heart Rate Variability

Some further search hits:


https://www.cultofmac.com/550061/apple-watch-heart-rate-variability/

https://elitehrv.com/what-is-heart-rate-variability

https://medium.com/@marco_alt/how-to-make-sense-of-your-apple-watch-...

I just bought the Forerunner 945 - Garmin's latest. The HR readings from the optical sensor measuring at the wrist that I get, especially at rest, are pretty far off. I generally run/ride with Wahoo armband monitor...I have no evidence those readings are more accurate other than they seem closer to what I'd expect. No experience with apps using HRV as a training metric...

I have been using HRV for a few years now. I've seen it be used by a handful of pro athletes as well/

I don't believe an optical HR sensor is good enough. I would go with a high quality strap.

There are a few devices you put on your finger that are very accurate and a bit less intrusive than putting s HR strap in the morning

There is an app that takes HRV using the iphone camera and it had good correlation with the values from a HR strap

The trick to HRV is not worry about an individual score but rather a trend over days and being able to correlate it to other things such as training load, sickness, stress and for me the most common issue, a beer too many the night before.