​Fitbit Charge 4 will now show oxygen saturation on the wrist

See blood oxygen saturation on the wrist
Wareable is reader-powered. If you click through using links on the site, we may earn an affiliate commission. Learn more

A new update for the Charge 4 is rolling out, which will let users view blood oxygen saturation from the wrist.

The update – spotted by 9to5Google – is part of a large package of new Charge 4 features that we reported on last month, with Charge 4 users also able to see a week’s worth of the company’s health metrics without a Premium subscription.

The Charge 4 already tracks blood oxygen levels at night in the Estimated Oxygen Variation feature, which is part of the advanced sleep tracking offering in Fitbit Premium.

That graph will show evidence of drops in blood oxygen in comparison to your personal baseline during sleep, and is essentially sleep apnea detection. However, despite having an SpO2 sensor from launch, there’s been no way to quickly check blood oxygen levels from the wrist.

Now Charge 4 users can see their oxygen saturation as a percentage on the wrist by swiping up from the home screen.

However, like the Fitbit Sense and Versa 3 which received the SpO2 watch face from launch, your oxygen saturation will only be shown from the last night’s sleep.

That means you still won’t be able to spot-check blood oxygen levels, as is the case on the Apple Watch Series 6 and even budget devices such as the Amazfit GTS 2 and Huawei Watch GT 2e.

That does somewhat undermine its usefulness for things like checking levels when at altitiude or perhaps when sick (although we would recommend using a medical grade SpO2 sensor in this instance). But blood oxygen during sleep is more reliable, and a useful tool in identifying some common sleep disorders.

The update 1.100.34 is rolling out now, so if you’re a Charge 4 owner look for the prompt to update in your Fitbit app.


How we test

James Stables


James is the co-founder of Wareable, and he has been a technology journalist for 15 years.

He started his career at Future Publishing, James became the features editor of T3 Magazine and T3.com and was a regular contributor to TechRadar – before leaving Future Publishing to found Wareable in 2014.

James has been at the helm of Wareable since 2014 and has become one of the leading experts in wearable technologies globally. He has reviewed, tested, and covered pretty much every wearable on the market, and is passionate about the evolving industry, and wearables helping people achieve healthier and happier lives.

Related stories