I do strenuous exercise most days, where "strenuous" means I'm close to my aerobic limit. I can tell I'm coming down with something a few days before I feel sick, because it nearly pushes me over the edge of what I can do. No technology, just "geez that was hard today".

I've seen others here report the same thing. It's interesting that it can also be picked up using technology monitoring the body's "at rest" metrics, but not that surprising.

As for who is buying it - the obvious candidate is businesses selling goods to nest-building new mothers. We've known this since Target gave away a daughter's pregnancy to her dad, via their ads: https://blog.othor.ai/the-target-pregnancy-prediction-analyt...

I see ample coverage of the "obsessively clicking refresh" aspects. But zero coverage of the "who's buying that fitness tracker data?" issues.

Did he send a notification to the father?