Wearable technology has come a long way in recent years. Smartwatches can now measure blood oxygen saturation (SpO2), a vital sign showing the oxygen level in your blood. While you can’t directly install SpO2 on your smartwatch as they come as an inbuilt feature, you can install an SpO2 clock face and app.

How Smartwatches Measure SpO2 Levels

A smartwatch’s capabilities are no longer limited to showing the time. With new innovations, a modern watch can measure your blood oxygen saturation levels (SpO2).

How does it do this? The SpO2 sensor passes red and infrared light into the body part that’s incontact with the watch and measures how much is absorbed. This tells how much hemoglobin there is in your bloodstream, which is necessary to breathe and sustain life. A higher level of hemoglobin means that your blood has a good supply of oxygen.

In fact, smartwatches with this technology can perform simple functions, like pulse rate measurement, heart-rate monitoring, and stress detection. They are also capable of measuring SpO2 levels without the need for an additional probe. There is a big advantage of using a smartwatch over other devices like a pulse oximeter: you can take the readings anytime, anywhere—provided that you have your watch on.

How to Install SpO2 on Your Smartwatch

There are different smartwatches on the market today, and all may have their own installation processes and apps. Let’s look at the three most popular options: Fitbit, Apple, Garmin, and Samsung Galaxy.

1. Fitbit Smartwatches

The Fitbit SpO2 smartwatch is intended for measuring oxygen levels passively during sleep. This means Fitbit devices are not recommended for real-time or continuous SpO2 monitoring.

How to Install the SpO2 Clock Face

Tap the Today tab from the Fitbit app.
Tap the profile picture, then your device image.
Select the Gallery option, then tap on the Clocks tab.
Search for SpO2.
Browse the clock faces available, and tap on the one that you want.
Select install, allow permissions, and follow the instructions for a successful installation.

Ensure your watch runs on the latest software version by installing updates, and do the same to the Fitbit app on your phone.

Some SpO2 clock faces are only available in certain countries. If you don’t see the feature on your smartphone, it may not be available in your region.

How to Install the SpO2 App

Some devices may come with the SpO2 app automatically installed. If you find that yours needs to be added, follow these steps:

Select the Today tab from the Fitbit app.
Tap on your profile picture, then select your device image.
Select the Gallery option.
Search for SpO2.
Tap SpO2 or SpO2 Tracker, then install.

Here’s another way to check your SpO2 levels on your Fitbit device:

In the Fitbit app, choose the Today tab.
Tap the button for Sleep.
Tap the sleep log date you want to view. This opens your Estimated Oxygen Variation graph for that date.

How to Check SpO2 levels

To view your recent SpO2 levels on your smartwatch SpO2 clock face, do the following:

Wear your watch overnight, and sync it in the morning.
Check your watch face to see your average resting SpO2 level.

Note that you should install the SpO2 clock face to access your readings on your Fitbit device. Also, give your smartwatch at least one hour to reflect the SpO2 measurements after syncing.

2. Apple Smartwatch

The Apple smartwatch allows you to customize your watch face. You can change the face, add complications to the clock face, and add a watch face to your collection.

How to Add an Apple Watch Face

Hold the touchscreen.
Swipe left until you reach the end.
Tap the plus sign (+) to add a new watch face.
Turn the Digital Crown to scroll through available options. You can browse specific collections for more watch faces.
Once you choose your watch face, tap Add.
From there, you can customize it to fit your style.

How to Change an Apple Watch Face

Hold the touchscreen of your watch and swipe until you reach your choice, then tap it.

How to Set Up the SpO2 App and Background Readings

Apple’s SpO2 smartwatch allows you to spot-check and track your oxygen levels when sleeping. You can find the SpO2 feature on Apple Watch Series 6 or later versions and iPhone 6s or later versions.

Open the Health app on your iPhone.
Follow the instructions displayed on the screen.

Do the following if there isn’t a setup prompt:

Select Browse.
Scroll to Respiratory.
Select Blood Oxygen, then Enable.
Open the app on your Apple Watch to check your blood oxygen saturation once setup is complete.

How to Take SpO2 Measurement Using an Apple Smartwatch

The Apple Watch Blood Oxygen App allows you to measure your SpO2 anytime, anywhere. However, you will need to stay still for at least 15 seconds to get the correct readings.

Here are the steps:

Ensure your watch fits snugly on your wrist; the back of your watch should touch your hand.

Open the app on your watch.
Ensure that your wrist is flat and that the watch faces up.
Hold still and tap Start.
Wait 15 seconds to complete the measurement.
Check the results displayed on the watch screen.
Tap Done.

The Apple smartphone with SpO2 has a background feature that allows it to measure your blood oxygen levels when you’re still. The number of readings will depend on the time you were not active.

Furthermore, the Apple watch allows you to take blood oxygen measurements during sleep, but only when you enable the sleep option.

Here’s how to view your health information on Apple.

Your iPhone’s health app stores all of your SpO2 readings. Do the following to access it:

Open the Health app from your iPhone.
Select the Browse tab > Respiratory > Blood Oxygen.

3. Garmin Smartwatch

Some Garmin smartwatches have SpO2 features, although they are available in select countries.

How to Install a Garmin Watch Face

Go to your Garmin Connect app on your phone.
From the side menu, select Connect IQ™ Store.
Select Watch Faces on the drop-down Menu.
Choose and tap on a watch face from the list.
Tap on Download, and you will notice that your phone is syncing with your watch.
After the download, you will see the new watch face on your watch.

How to Change Your Garmin Watch Face

From the watch face, hold down the B icon.
Tap Watch Face.
Swipe right or left to see available watch faces.
When you locate your desired watch face, tap on the touchscreen to apply your new watch face.

Note that you can use the above steps to install apps on your Garmin smartwatch.

How to Spot-Check SpO2 Using Garmin Watch

The Garmin smartwatch comes with a SpO2 feature called Pulse Ox. It allows you to take spot-checks and SpO2 during sleep.

Go to your Garmin watch menu.
Ensure your wrist is flat, then select the Pulse Ox widget.

How to Enable SpO2 Tracking All Day or During Sleep

From the Garmin Connect app, navigate to Menu.
For Android, select the icon on the top left. For iOS, select More on the bottom right.
Select Garmin Devices to choose your watch if you have other devices installed.
Tap Activity Tracking.
Select Pulse Ox.
Switch between Tracking or All-Day Tracking

How to View Spot-Check and All-Day Readings

From the clock face, scroll Down to the Pulse Ox widget.
Allow a Spot Check measurement.
Select Start to view All-Day measurements.

To View Sleep Pulse Ox Measurements

From the Garmin Connect app, navigate to Menu.
Select the icon on the top left for Android and More on the bottom right for iOS.
Select Health Stats.
Tap Sleep.
Select Pulse Ox from the three tabs displayed.

4. Samsung Galaxy

Samsung has different smartwatches that offer SpO2 features. The Samsung Galaxy Watch 4 and Galaxy Watch 5 series can spot-check and track blood oxygen levels during sleep.

How to Install Watch Face for Samsung Galaxy Smartwatch

There are two ways you can download a watch face for your Samsung Galaxy Smartwatch: using an app or from your watch.

Using the Galaxy App

Open the Galaxy Wearable app from your phone and tap Watch faces.
Swipe until you get one you like, then tap it.
To download more clock faces, choose one from the Get More Watch Faces option at the bottom of the screen.

Using the Watch

Touch and hold the current watch face to activate the Edit mode.
Select the watch face you want by swiping left and tapping on the Add Watch Face option.
Swipe left until you see More Watch Faces. Tap on it to open the Play Store.
Browse and choose the one you like, then tap Install.

How to Add the Blood Oxygen Tile

From the home screen, swipe left through the available options.
Tap on Add Tile and scroll to locate Blood Oxygen.
Select Blood Oxygen to add it to your tiles.

How to Take Spot-Check Measurements

Swipe from the watch’s home screen until you reach the Blood Oxygen tile.

Tape Measure.
Swipe left to follow the instructions.
Tap OK.

How to Enable SpO2 Measurements during Sleep

Swipe up on the home screen to get to the Menu.
Select Settings, and scroll down to find the Samsung Health option.
Tap Samsung Health, and scroll down to Blood Oxygen Level during Sleep.
Tap on it.

You can connect your Galaxy smartwatch with the Samsung Health app to access SpO2 readings across Samsung devices.

What Are the Factors That Affect SpO2 Measurement?

A few factors can affect the accuracy of SpO2 measurements taken with a smartwatch.

Skin pigmentation: Recent studies show that dark skin pigmentation affects the accuracy and performance of smartwatches. The signaling process does not work well with darker skin tones.
Changes in your skin: Patterns, inks, and tattoos can reduce the effectiveness of SpO2 smartwatches by blocking light from the sensor.
Perfusion: Perfusion refers to blood flowing to organs or tissue. The SpO2 sensor can’t get an accurate reading if there is insufficient blood flow.
Motion: The watch will get inaccurate measurements if you move around a lot.
Skin temperature: Too cold or too hot body temperature can lead to inaccurate oxygen levels.
Posture: Holding your wrist incorrectly can affect your SpO2 metrics.

Which Is More Accurate for SPO2: A Smartwatch or an Oximeter?

Smartwatches are more convenient and comfortable to wear but are usually less accurate than oximeters when measuring oxygen saturation in the blood. Oximeters are more accurate but can be bulky and uncomfortable to wear for extended periods.

Will Using the SpO2 Feature Affect the Battery Life of My Smartwatch?

Yes, using the SpO2 feature can affect your device’s battery life. The effects on battery life will vary depending on the device and other factors. You may charge your device more, especially if you turn on All-Day or Sleep tracking features.

Final Thoughts

Installing the SpO2 watch face and apps on your smartwatch is easy if you follow the instructions correctly. These smartwatches are essential for monitoring your fitness and wellness levels. They can also alert you on potential health conditions, such as pulmonary embolism or sleep apnea.

Smartwatches with SpO2 are often marketed as providing accurate readings of blood oxygen saturation. However, most of them are not cleared by the US Food and Drug Administration (FDA), meaning they are not to be used for medical purposes. Use your pulse oximeter, especially if you have an underlying condition that might reduce your blood oxygen saturation.

How To Install SpO2 On Smartwatch