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How to use the Apple Watch 6 Blood Oxygen app

Apple Watch blood oxygen app
(Image credit: Future)

The Apple Watch blood oxygen app, available to those with the Apple Watch Series 6, can be used to administer at-home SpO2 readings. Similar to finger-based pulse oximeters, Apple's flagship smartwatch can give you a sense of your body's oxygen saturation without you needing to get your blood drawn in a lab.

Many of the best smartwatches also offer blood oxygen readings, but the Apple Watch is the most popular of the bunch. And as the Series 6's exclusive feature, you might be wondering how to use the Apple Watch Blood Oxygen app if you've recently acquired Apple's latest flagship.

Although the Apple Watch earned its category-leading reputation by making things easy, reviewers and users alike have run into some issues with fielding accurate blood oxygen readings. We've had more success, but we've also spent several weeks now brushing on Apple's blood oxygen app guidance and understanding which variables impact our readings. 

Here's our guide on how to use the Apple Watch Blood Oxygen app, including what we know about the reading accuracy and tips on what do if you're experiencing unsuccessful measurements.

Is the Apple Watch Blood Oxygen app accurate?

First thing's first: The Apple Watch Blood Oxygen app is NOT approved by the FDA. Unlike the Apple Watch's electrocardiogram (ECG) reader, the Blood Oxygen app doesn't have the public health stamp of approval, meaning it cannot diagnose you based on your readings. Apple even provides a disclaimer within the app that its Blood Oxygen measurements are not intended for medical use. 

The Apple Watch Blood Oxygen app offers a brief blood oxygen synopsis and explains how readings of 95%-100% are considered average, although factors like high altitude and non-life-threatening sleep conditions could result in abnormal readings. 

Below-average readings can also be a symptom of a lung condition such as silent hypoxia, a life-threatening condition that can escalate the effects of respiratory illness. 

If you field a low blood oxygen reading, but have no irregular respiratory symptoms, your reading might not be accurate. We explain some factors that could be causing that below. That said, if you're experiencing shortness of breath, coughing or wheezing and are concerned about your blood oxygen reading, you should reach out to your doctor.

How to use the Apple Watch Blood Oxygen app

In order to use the Apple Watch Blood Oxygen app, you must have the Apple Watch Series 6. Neither the Apple Watch SE nor Apple Watch Series 3 support SpO2 readings. 

1. Open the Blood Oxygen app on your Apple Watch. If you plan to take readings regularly, it could make things easier for you to place the Blood Oxygen app complication on your watch face.

apple watch blood oxygen app

(Image credit: Future)

2. Rest your arm and wrist on a flat surface, and make sure your Apple Watch is facing up. Apple says you can rest your arm on your lap, too, but we've found more success by using a flat surface. Prepare to keep your arm still.

Apple Watch blood oxygen app

(Image credit: Future)

3. Click start measurement. Keep your arm steady for 15 seconds.

Apple Watch blood oxygen app

(Image credit: Future)

4. Wait 15 seconds. If your Apple Watch was able to get a reading, you should see your blood oxygen level. Hit the information icon next to your reading to learn more about the Apple Watch blood oxygen app, or hit done to finish.

apple watch blood oxygen app

(Image credit: Future)

Apple Watch Blood Oxygen app not working? What to do about unsuccessful measurements

There are a couple of factors that may cause the Apple Watch Blood Oxygen app to read, "Unsuccessful Measurement," when you take a reading. Although your Apple Watch won't tell you which of those factors you need to adjust, here are some tips for getting the app to work properly.

1. Don't move during the reading. Even if you wiggle your fingers or adjust your arm, you could experience an unsuccessful reading. Be sure to get your arm and wrist into position prior to pressing start.

apple watch blood oxygen app

(Image credit: Future)

2. Make sure your Apple Watch is snug on your wrist. The back of your Apple Watch should be touching your wrist. If your Apple Watch is loose on your wrist, tighten your Apple Watch band. Apple's stretchy Braided Solo Loop and standard Solo Loop are great for a secure fit, so long as you have the right size

Apple Watch 6

(Image credit: Future)

Even under the right conditions, your Apple Watch may not be able to get a reliable blood oxygen measurement every time. Tattoos, high heart rate and skin perfusion could also result in unsuccessful readings. Experiment with different factors and placements on your wrist to find what works for you. 

Check out our guide on how to use the Apple Watch for more tips and tricks on making the most of your smartwatch.