Can the watch and app monitor o2 levels while I sleep and give me a report of ups and downs?

Hello SFtoad,

We see you have a question regarding blood oxygen monitoring on your Apple Watch, and we can help out.

This page here will help to see where you can find the info on that, particularly in the "View your Health information" section: How to use the Blood Oxygen app on Apple Watch Series 6 or Series 7

As the noted section will mention, "You can also filter and view measurements taken only while sleeping or in a high-elevation environment."

If you happen to have further questions or any issues with the Blood Oxygen app, you can reach out here to Apple Support's Advisors that specialize in that area: Get Support

Cheers.

SFtoad,

You're very welcome! It's always our pleasure to help out.

Take care.