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Fitbit enables SpO2 monitoring on five wearables

One new metric to keep an eye on

For years, some of Fitbit’s most popular devices have had a hidden ability, and today the company has unlocked it for five eligible wearables.

Estimated Oxygen Variation – also known as “peripheral capillary oxygen saturation” or SpO2 – has today rolled out to all Charge 3, Ionic, Versa, Versa Lite and Versa 2 models after a limited trial last month. 

It’s just those five, unfortunately – the sub-£100 Fitbits just don’t have the required sensors. The new feature uses the red and infrared sensors on the back of each wearable to estimate how much oxygen there is in your bloodstream while you sleep. 

That all sounds very technical – and of course it is – but all the layman really needs to know is that for a typical, healthy person, said saturation level is between 95% and 100%. That means if it falls below this level, then you may have stopped breathing or have other lung-related issues that could benefit from a professional medical opinion. 

At a less severe level, variations in SpO2 tend to be small and infrequent. Larger variations overnight suggest that you’re having breathing disturbances while you sleep, possibly sleep apnea. 
As Fitbit says within the app: “Blood oxygen saturation normally fluctuates, but high variations can be linked to breathing issues. Estimated oxygen variation approximates the changes in your blood oxygen saturation.”

Despite these links to health, Fitbit is quite careful to state that the sensor is not intended for medical purposes. One non-medical purpose, incidentally, is the ability to check you’re acclimatising when training at altitude.

Although the feature is only just arriving now, it has been known about for quite some time, and Fitbit was excited enough about the potential to include it in the press release for the release of the Ionic way back in 2017. “The introduction of a relative SpO2 sensor for estimating blood oxygen levels opens the potential for tracking important new indicators about your health, such as sleep apnea,” the company wrote.

It’s worth noting that Fitbit isn’t the only company to offer SpO2 analysis. Garmin wearables including the Vivosmart 4 and Forerunner 245 have it in, and you can even get it super cheap if you buy the Honor Band 5, which comes in at just £30.

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