I have the Apple Watch and I hardly ever check the stats but every few months it pings me with something like "Over the last 5 days, your resting heart rate dropped" which was a period I was on holidays, made me wonder if it was the lack of access to coffee, or just a more inactive period where I sat in a car most of the time.

The long term data can be interesting. Moved apartments and saw my elevation climbed stat went up as the local area was not so flat