The Blood Oxygen app on your Apple Watch can allow you to measure the oxygen level of your blood on-demand directly from your wrist. But note that these measurements are for general fitness and wellness purposes, not for medical use.
What is blood oxygen?
Your blood oxygen level represents the percentage of oxygen your red blood cells carry from your lungs to the rest of your body. Knowing how well your blood performs this vital task can help you understand your overall wellness.
The majority of people have a blood oxygen level of 95 – 100%. However, some people live a normal life with blood oxygen levels below 95%. Slightly lower values while sleeping are expected, and some users might experience values below 95%.
Here’s what you need to use the Blood Oxygen
° Make sure that the Blood Oxygen app is available in your country or region. You will be able to see this during the setup process
° Update your iPhone 6s or later to the latest version of iOS.
° Update your Apple Watch Series 6, or Series 7, Series 8, or Ultra to the latest version of watchOS.
° Note that the Blood Oxygen app is not available for use by people under 18 years old. You can confirm or set up your age in your Health Profile.
How to set up the Blood Oxygen app
° On your iPhone, open the Health app.
° Follow the onscreen steps. If you don’t see a prompt to set up, tap the Browse tab, then tap Respiratory > Blood Oxygen > Enable.
° After you complete setup, open the Blood Oxygen app on your Apple Watch to measure your blood oxygen levels.
If you still don’t see the Blood Oxygen app on your Apple Watch, you can search the App Store on your Apple Watch for Blood Oxygen and download it.
The Blood Oxygen app is installed during the setup in the Health app. If you deleted the Blood Oxygen app, you can install it again from the App Store on your Apple Watch if you’ve completed the Blood Oxygen app setup.
How to take a blood oxygen measurement
You can take a blood oxygen measurement at any time with the Blood Oxygen app. To do so:
° Make sure that your Apple Watch is snug but comfortable on your wrist.
° Launch the Blood Oxygen app on your Apple Watch.
° Stay still, and make sure your wrist is flat with the Apple Watch facing up.
° Tap Start, then keep your arm steady for 15 seconds.
° Wait. The measurement takes 15 seconds. At the end of the measurement, you will receive the results.
° Tap Done.
How to view the results
All blood oxygen measurements, whether on-demand or in the background, are saved in the Health app on your iPhone.
° Open the Health app.
° Tap the Browse tab, then tap Respiratory > Blood Oxygen.
You can also filter and view measurements taken only while sleeping or in a high-elevation environment.
(This how-to is based on my experiences and info on Apple’s support pages — where the images sometimes come from.)