Tracking blood oxygen saturation (SpO2) is one of the most popular health features on wearables, and shifts in your SpO2 are often an early indicator of changes in your fitness and wellness.
Athletes and high-altitude sports enthusiasts use the blood oxygen saturation metric to monitor performance. And regular people use this metric to help identify health conditions, such as respiratory illnesses or breathing issues when sleeping, like sleep apnea. And looking at changes in your blood oxygen can also give you and your healthcare team important insights into various health-related problems.
Unlike other wearables, your Fitbit device uses its sensors to estimate your blood oxygen saturation (SpO2) while you sleep (for at least 3 hours) and does not currently offer an on-demand way to see your SpO2 in real-time.
So, if you wear your Fitbit to bed and don’t see a SpO2 percentage the following day or have other problems with getting your Fitbit to take SpO2 readings, such as getting the message that your Fitbit “couldn’t read SpO2,” this article is for you!
Sadly, these are common issues experienced by many Fitbit users. Keep reading to understand what Fitbit SpO2 is and some fixes to help you to solve this issue.
- 1 What is SpO2?
- 2 I’m not getting SpO2 values on my Fitbit. How do I fix it?
- 2.1 Verify you live in a supported country/region setting
- 2.2 Refresh your clock face data
- 2.3 Sync your Fitbit after sleeping
- 2.4 Reboot your phone and Fitbit device
- 2.5 Update the Fitbit app and allow it to refresh in the background
- 2.6 Check that your Fitbit runs its latest firmware
- 2.7 Uninstall and reinstall the SpO2 app and/or remove the clock face and re-add it
- 2.8 Fully charge your Fitbit
- 2.9 Check your permissions
- 2.10 Change your Fitbit position
- 3 Why is my Fitbit’s SpO2 giving me inconsistent readings?
- 4 Final thoughts
- Pixel Watch not syncing heart rate, activity, or sleep data to Fitbit app? Fix it
- 5 best smart scales that work with the Fitbit app
- Fitbit not tracking distance on bike rides or is inaccurate? Let’s get it working
What is SpO2?
After you breathe in oxygen, it enters your lungs and bloodstream.
The amount of oxygen in your bloodstream (oxygen-saturated hemoglobin relative to total hemoglobin) is your blood oxygen level or oxygen saturation level. This is called SpO2 (peripheral capillary oxygen saturation).
Your body needs a certain amount of oxygen to function properly. Normal daytime Sp02 levels are between 97–100 percent.
Nighttime SpO2 is usually lower than daytime SpO2. This is because your breathing rate is generally slower during sleep. SpO2 values during sleep can typically be as low as 90%.
If your SpO2 value is below 90%, that could be a sign of poor blood oxygenation. Good blood oxygenation is necessary to supply the energy your muscles and organs need to function correctly.
How is blood oxygen (SpO2) measured on my Fitbit?
On wearables like Fitbit, SpO2 is measured by Pulseimetry, a non-invasive method that works by emitting and then absorbing a light wave that is usually passed through your blood vessels in the skin area underneath the wearable device (or for other devices like the kind used in medical facilities, the fingertip.)
The light wave passing through the blood vessel gives the value of the SpO2 because the amount of oxygen saturation causes variations in the blood’s color.
Richly oxygenated blood reflects more red light than infrared light.
Your Fitbit device measures your SpO2 levels while you sleep using red and infrared sensors on the back of the device.
The sensors shine red and infrared light onto your skin and blood vessels and use the reflected light that bounces back to estimate how much oxygen is in your blood. You might see the red and infrared sensors blink for around 30 minutes after you wake up.
Why is Fitbit measuring SpO2 only during sleep?
The Fitbit SpO2 values are an estimate that your activity, altitude, and overall health can influence. Blood oxygen tends to increase during physical activity, which is why levels are measured during sleep.
Your body adapts to different oxygenation levels during physical activity by increasing your breathing rate. As your breathing rate increases, your blood oxygen levels can increase.
Fitbit SpO2 displays your SpO2 percentage detected during sleep as an average and the range of values collected.
The Fitbit SpO2 values can range from 80% – 100%. Fitbit SpO2 does not measure or display SpO2 values lower than 80%. Any measurement lower than 80% is shown as “<80%.”
Do I need to subscribe to Fitbit Premium to see my blood oxygen levels?
You do not need to subscribe to Fitbit Premium for your Fitbit to track and record your blood oxygen level while sleeping each night.
However, if you want to see how your SpO2 varies over time (its history and trends for one month+), you need to subscribe to Fitbit Premium.
- The free, basic Fitbit membership includes one week of your Sp02 readings.
- The paid, premium Fitbit membership includes one month of your Sp02 readings. You can also download a historical report for SpO2 readings older than one month. Fitbit premium has snore and noise detection, sleeping heart rate, and restlessness. You also get a daily readiness score and other advanced health reports and tools.
Install the SpO2 app or clockface
To see SpO2 readings, you need first to install the SpO2 app on your Fitbit device (Sense, Versa 3, Charge 4+, and Luxe ) or install a SpO2 clock face on your device (Ionic, Sense, Versa series.)
For the Sense series and Versa 3+, you can install a SpO2 clock face or the SpO2 app to collect this data. You do not need both.
- Install the SpO2 app via the Fitbit app’s App Gallery. Search for and install the SpO2 app or SpO2 Tracker app. Make sure you allow the app all permissions.
- Install the SpO2 watch face via the Fitbit app’s Clock face Gallery. Search for and install one of Fitbit’s SpO2 clock faces. Make sure you allow the app all permissions.
Where do I find my SpO2 data?
After getting a whole night’s sleep, open the Fitbit app, sync with your device (it can take up to an hour for your SpO2 values to appear after you sync your device), and choose the Today tab > Health Metrics tile (not in Sleep info) to see your last sleep’s SpO2 readings.
The Health Metrics tile is available with Charge 4+, Inspire 3+, Luxe, Sense series, and Versa 2+ devices.
When you use a SpO2 app or clock face, you should see your oxygen level for your most recent sleep right on your watch face or in the Today app on your watch.
If your sleep was interrupted (or you slept for over 3 hours multiple times during the day/night) and your sleep stage info is split into 2+ separate logs, your clock face shows the SpO2 percentage for the most recent sleep. It does not combine the logs or show more than one log.
When you use a SpO2 app or clock face, it does take some time (up to an hour) to appear after waking, so if you don’t see it right away, check again later.
About the Sleep tile’s oxygen variation
As mentioned above, you won’t see your SpO2 percentage in the Sleep tile’s sleep score breakdown. But you see a graph of your estimated oxygen variation, which shows any major fluctuations in your oxygen saturation while sleeping.
Estimated oxygen variation (EOV) estimates the changes in your blood oxygen saturation levels. It helps you see specific times overnight when your blood oxygen saturation levels vary, which might indicate breathing disturbances.
I’m not getting SpO2 values on my Fitbit. How do I fix it?
Are you seeing dashed lines on the clock face or SpO2 tile, a message that the SpO2 data couldn’t be read, or missing data in the Health Metrics tile in the Fitbit app on your phone?
Or perhaps some days you are getting SpO2 readings, and other days, you are not?
If you aren’t getting readings, here are ten fixes to help you solve this issue!
Verify you live in a supported country/region setting
- Ensure you have the region set to the correct country you currently reside in (don’t change this setting when visiting other parts of the world.)
- The SpO2 clock face feature is not available in all countries. If you don’t see it in the SpO2 Fitbit Clock face in the gallery under the clock taps, then it’s not available for your country or region.
Also, you may find that your Fitbit won’t record your SpO2 when traveling overseas in a country that doesn’t allow this feature. The feature should work when you get back to your home region. You don’t need to do anything to re-enable it.
Refresh your clock face data
Try refreshing your clockface’s data to the latest stats from Fitbit.
Open the Today app on your Fitbit and then go back to the clockface to see if it refreshes the SpO2 and other data.
Sync your Fitbit after sleeping
Your device must sync with the Fitbit app before the clock face or health metrics tiles update. You can wait for it to sync automatically in the background or manually force the app to sync to your device.
You can manually update the app by tapping the Sync Now button or pulling down the Today tab’s screen.
- Open the Fitbit app and choose the Devices icon at the top left.
- Under Connected to Fitbit, tap your Fitbit device.
- Scroll down and tap Sync Now.
You can also force a sync between your device and the Fitbit app using the Today tab by pulling down from the top of the screen.
It may take around an hour for your SpO2 values to appear after you sync your device with the app.
Clear the Fitbit app cache
While Android phones offer an option to clear the Fitbit app’s cache, you don’t find that option on iPhones. However, you can close the Fitbit app on your iPhone, which automatically removes some temporary files.
- For Android, clear the cache by going to Settings > Apps > Fitbit > Storage & cache > Clear cache.
- For Apple iPhones, close the Fitbit app by swiping up from the bottom of your phone until you see smaller app previews. Locate the Fitbit app and then swipe it up off the top of your screen.
Reboot your phone and Fitbit device
Some users have reported restarting their phones, and Fitbit devices have solved this issue.
- To reboot your phone, power it off, wait 20-30 seconds, then power it back on.
- To reboot your device, open the Settings app and choose Shutdown (wait for 20 seconds and press the side button to power back on) or Restart device > Restart. For exact steps by model, see this article.
Update the Fitbit app and allow it to refresh in the background
Keep the app up-to-date, so the app runs the latest version with all the bug fixes and algorithm updates.
To update the Fitbit app on your phone, open the App Store or Google Play app and search for Fitbit. If an update is listed, tap it.
Once updated (if applicable), verify that you allowed it to run in the background.
- For iPhones, open Settings > Fitbit and toggle on Background App Refresh.
- For Android, open Settings > Apps > Fitbit > Mobile data & Wi-Fi and toggle on Background data and Unrestricted data usage.
Check that your Fitbit runs its latest firmware
To see what version your device runs, open the Fitbit app > Devices icon > your Fitbit. The current firmware version number appears under your Fitbit’s name.
When there’s an update, you see a banner to update your tracker.
If you see an update banner in the Fitbit app, tap it and follow the steps to update your device’s operating software. When your Fitbit is new to you, allow up to 48 hours to install all necessary updates and features after initially setting your Fitbit up.
On some models, you can also find this information in the device’s Settings app and choose About or Device Info > System Info > Version.
Uninstall and reinstall the SpO2 app and/or remove the clock face and re-add it
Sometimes, removing the old version of the app or clockface and reinstalling it with the latest version gets your Fitbit to capture your SpO2 data again.
First, uninstall the app and then the clock face. Then add them back.
- To uninstall/reinstall the SpO2 app, open the Fitbit app > Devices icon > your Fitbit.
- Select Gallery. The app should default to the tap tab for your Fitbit.
- Under My Apps, locate the SpO2 Tracker or SpO2 app and select Uninstall and confirm.
- To uninstall a SpO2 clock face, change your current Fitbit’s clockface to a non-SpO2 clockface via the Gallery > Clocks. Once you change the clockface, choose your Fitbit device at the top tab and scroll to My Clocks and tap your SpO2 clock face. Scroll to the bottom and tap Remove clock face and confirm.
After removing the SpO2 clockface and uninstalling the SpO2 app, reinstall the app or the clockface via the Gallery > App tab. Make sure you allow all asked permissions.
Then, wear your Fitbit to bed for a few nights (sometimes, one night is sufficient to get your data, but you may need as many as three consecutive nights) and check if you get your blood oxygen information.
Fully charge your Fitbit
Charge your Fitbit device to make sure it’s able to collect data throughout your entire sleep session. You want your Fitbit to have at least 30% battery before bed.
You may have to charge your Fitbit more often when using a SpO2 clock face or SpO2 app.
Check your permissions
Ensure permissions are turned on. Turning off any SpO2 clock face or app permissions stops the feature from working.
Verify SpO2 clock face permissions
- Open the Fitbit app on your phone.
- Tap the Devices icon > your Fitbit.
- Choose Gallery and select your Fitbit device tab at the top (if it’s not already selected.)
- Tap your current SpO2 clock face, or under My Clocks, select the SpO2 clock face you use.
- Scroll down and select See all details.
- Tap Permissions.
- Turn on all permissions. If they are all on, toggle them off, wait a few seconds, and toggle them back on.
Change your Fitbit position
Try wearing your device slightly higher on your wrist and on the inside of the arm instead of the outside. Your device should be a snug fit but not constricting.
This is especially useful if you have tattoos or have a lot of arm hair (you could also shave your hair but wearing it on the inside is a lot easier!)
I find that wearing my Fitbit on the inside of my wrist/arm helps my Fitbit more consistently and accurately measure my SpO2, heart rate, and other measurements.
Why is my Fitbit’s SpO2 giving me inconsistent readings?
You may be getting inconsistent readings or days with missing data if you are not sleeping uninterrupted for more than 3 hours per night or the sensors are losing contact with your skin while sleeping.
This may be because you move a lot while sleeping, there is sweat between the band and the skin, or the band is too loose. In these cases, there is insufficient data about your oxygen saturation to give a SpO2 reading.
What can affect my Fitbit Sp02 reading?
Several factors can affect your body’s ability to maintain blood oxygen levels. A change in these factors can affect your SpO2 values.
- High altitude conditions can reduce your SpO2 because the air contains less oxygen if your SpO2 values are low, while at high altitudes, you can descend to a lower altitude to increase your SpO2 reading.
- Sleeping patterns and quality can reduce your SpO2 data collected. If you move a lot during your sleep or have trouble sleeping ( less than 3 hours), you might not get SpO2 data because data is only collected when you’re still.
- Health problems such as COPD, heart disease, and anemia can reduce the body’s ability to take oxygen into the bloodstream. Health conditions such as these can cause a lower-than-normal SpO2.
- External factors can also interfere with collecting your SpO2 reading, such as dirty skin, bright lights, skin temperature, darker skin tones, tattoos, and poor circulation.
If you have a health condition, you should not rely on Fitbit SpO2 for monitoring your condition or for any related medical purpose. You should consult your healthcare provider if you have concerns about your SpO2 or your health.
Sp02 is an excellent feature for monitoring your wellness and oxygen levels while sleeping. If you are healthy and are interested in seeing your SpO2 data, this Fitbit feature is for you.
The Pros & Cons of Using a Fitbit To Track Your SpO2 and Sleep Quality
- A convenient way to see your SpO2 data without using an additional device
- Easy to understand reading, with a percentage value and a range of the values collected.
- It may give you early warning of health problems and prompt a visit to your healthcare provider.
- SpO2 data is only measured when sleeping.
- Gives an average SpO2 reading and not immediate real-time live readings, unlike other wearables, like Apple Watch.
The Fitbit SpO2 feature is intended only for general wellness and is not a substitute for medical care.
If you have a health condition such as COPD and want to monitor your SpO2 buying a Pulseimetry finger device is more appropriate to give you current, accurate readings. Consult your healthcare team for any concerns or questions about your SpO2 readings.