Has anyone had a problem with the oxygen monitor not working while you're asleep.
Solved! Go to Solution.
One of my colleagues confirmed what Nickh101 said in their updated OP: BUH9 update for the Watch should have this feature now:
They've advised that once the update is installed, update the Samsung Health app and make sure it's turned on.
And another user here: https://eu.community.samsung.com/t5/wearables/galaxy-watch-4-classic-oxygen-sleep-not-working/m-p/38... has also confirmed the feature works for them now.
Same here, Watch 4, blood oxygen works fine manually but does not record whilst sleeping even though selected on in the SH app.
The US community has a thread similar to this, hopefully it gets sorted in an update soon.
You have to open the Samsung Health app on the watch and scroll down to settings and go to "Measurements" and under "Blood oxygen during sleep" you pick "Measure constantly" - by default it's set to "Don't measure" even if you set it up everywhere else.