How long does PulseOx tracking work during sleep?

It works 24/7 and detracts one day of battery use if you choose to enable it. However...

Garmin ecosystem is still VERY early and there are HR sensor problems and bugs every where... I would wait a couple of years, atleast until every device is Airplane mode enabled from setting (it works if you only sync with pc) before strapping one of these things on my wrist.

In this market, I would reccomend Galaxy Active 2 instead, some of the same quirks (cant count stairs) But it has a fully baked OS that wont make you crazy.... BP and ECG coming, probably VO2 max as well. And a great sleep widget that works for sleep as well as naps(!)

I've got both and the Galaxy active 2 is much more reliable in the sensor department, the os look and feel is great, plus the passform on my wrist and no monthly updates that disrupts the functioning of the device. It is a much calmer purchase...

This is just my two cents after 11 months with the V4 and 9 months with the galaxy active 2.

I should note that I never connect these devices to a phone, my experience is without making changes to the os or install any applications, to make sure they are running without additional software complications.

There is also a discussion that has more info at https://forums.garmin.com/sports-fitness/healthandwellness/f/vivoactive-4-series/235468/new-sleep-widget-on-vivoactive-4

Yes it does have a 24/7 mode... and also it has the feature to record only during sleep which is a user defined window of time. SO yes, it works through your whole sleeping period.

It's not on constantly, but at least during sleep tracking, it stays on quite long, perhaps a couple minutes, and it works at set intervals. Not sure at which intervals though.

For me it works quite well, but I see no point in it for my personal use. Your criteria might be different. 

It does chew through considerable more battery. If I were guessing perhaps almost double your nightly average without PulseOx.

Agree that it does impact battery. To me it seems worth it for sleep because I have found that if I wear the watch overnight and have it turned on for sleep I end up at around 70% battery each morning. Then, it charges fairly fast so if I charge it while I shower and dress it is back to 100% by the time I put it back on.

30% overnight? Thats way too high...

At most I get around 10-11% consumption from 22:00 to 6am

It's 30% in a 24 hour period that includes PulseOx overnight. That includes email notifications for my work email which are a bit intense :(. And AOD. I am coming from a Samsung Active 2 that would get down into the 40% range by morning and took 2 hours for a charge. For me the VA4 is perfectly fine.

Oh ok

I was asking about the period because the vivosmart4 just records the first ~4h of sleep and then just stops.

So you can't really use it. 

Like I said, tracks for the entire user defined sleep period, but in intervals of every 30 min or so. 

I have seen other threads that also say it is only 4 hours but I do get tracking all night too. Was there maybe an upgrade that changed this?