Only for users with an Apple Watch Series 6 or above that allows blood oxygen measurements, an SpO2 tile will appear if you have background measurements enabled. If you do not measure sleeping blood oxygen then this till will not be visible.
SpO2 represents the percentage of the haemoglobin in your red blood cells that are carrying oxygen from the lungs to the rest of your body.
The white gauge needle shows your average from all the measurements of SpO2 during sleep. The blue range behind the gauge needle indicates the minimum and maximum measurements captured during the sleep session. The outer inlay represents your 7 day averages, with a black mark showing the 7 day average, and the range showing the 7 day minimum and maximum averages.
Studies have shown that the average SpO2 during sleep in healthy individuals is 95% to 97%. This drops lower with age to between 93-97% for those over 60. The colour parts of outer gauge (dark red, light red, orange and green) represent these ranges.
An SpO2 report can also be viewed in the Clock tab under the Wellness section.
Note: unless background measurements are enabled in the below points, you may not see the tile appear in the Today view
Setting Up SpO2
(1) Enable Blood Oxygen Permission
Blood Oxygen in the health permissions needs to be on to see SpO2 in AutoSleep. To check:
Go into the Health app (white icon with red heart), tap on Sharing tab, tap into Apps, then click on AutoSleep
Find AutoSleep in the list and make sure that Blood Oxygen is turned on for Read and Write permissions
(2) Enable Blood Oxygen Measurements
Its important to ensure the following steps are setup correctly to allow your Apple Watch to measure your blood oxygen while you sleep.
Open the Apple Watch settings app (you can find it on your iPhone by looking for a black icon with an image of a Watch, see below)
2. Blood oxygen measurements only occur during sleep if the Track Sleep with Apple Watch setting is turned on. While in the Watch app, scroll down and tap into Sleep, you will see a switch to enable called 'Track Sleep with Apple Watch'. See below:
3. Next while still in the Watch app, scroll down and tap on 'Blood Oxygen':
4. Now the important part, make sure all the toggles are switched on, especially the 'Allow Background Measurements'. It should look similar to the image below, depending on your region the switch names may alter a little.
Note: Apple restricts measuring blood oxygen if the age in Health is under 18 years. This can sometimes catch out users who may have swapped iPhones with their children and have not updated their date of birth.
Sleep SpO2 Details
On the Today view, tap on the Sleep SpO2 tile to view more details and trends.
Tap on any of the metrics below the sleep rings to open more information and see trends.
Tap on the Average or Range links to open your trends over a period of time, including maximums, minimums and rolling averages. An SpO2 Report will display showing your current average along with a 7 day and 28 day average so you can accurately track your measurements. You can tap any part of the graph to display a pop-up box with additional information.
SpO2 Measurements on the Sleep Graph
We have found that the Apple Watch will collect anywhere between 10-20 SpO2 measurements a night, depending on your sleep duration, activity and Watch positioning. SpO2 measurements during the sleep session can be seen in the below image as the green squares. Refer to the Sleep graph to see all your SpO2 recordings during the night.
Sleep SpO2 Compared to Daytime SpO2
When you wake up, we recommend performing a manual SpO2 reading using the Blood Oxygen app. This will record a daytime baseline which can be seen in the AutoSleep SpO2 Report on the Sleep page. This lets you compare a daytime average against your sleep average.