I found the following 2 pieces (and their underlying studies) very interesting.
New Study Reveals Holes in Wearable Device Scores
Adjust Your Training According to your Feelings
While studying different things, they both seem to have a similar conclusion. Develop your own sense of how tired you are and adjust your training based on your internal feelings. Studies have shown that this is more accurate than other measurements/readiness scores.
This is not really surprising to me. I have tracked HRV for some time. It is interesting to look at, and at times confirms some of my feelings. But would never use it as the sole source or a go/no go decision for training.
What this says specifically for Whoop…well, not surprised at that either.