Tucked away in some Garmin watches is a sensor that enables blood oxygen monitoring around the clock, with the company referring to this as 'Pulse Ox'.
You may have seen the feature appear in menus or in Garmin Connect's My Day, and there are some basics relating to blood oxygen readings (or SpO2 readings, as they're sometimes referred to) to understand in order to really get the most out of them.
Below, we've run through everything there is to know about the Garmin feature, including which watches it's available on and how you can enable it during sleep.
What is Garmin Pulse Ox?
Pulse oximetry is a reading that aims to establish how much oxygen is flowing in your bloodstream compared to its maximum capacity.
Delivered as a percentage figure (with higher percentages being more favorable), this is determined by shining light into the skin and measuring how much light is absorbed.
Garmin's particular method of pulse oximetry examines smaller vessels in the skin, which is known as peripheral oxygen saturation (SpO2).
Anything between 90% - 100% saturation is considered normal by the Mayo Clinic, with anything less than this considered low.
For those at altitude or involved in an activity, this figure will often be temporarily lower than their usual average, and this figure can also be affected by compromised blood flow.
And while Garmin watches aren't designed to be used as diagnostic tools, one of the primary uses for Pulse Ox is to monitor during sleep, given the relationship between low blood oxygen saturation and conditions such as sleep apnea.
How to take a Pulse Ox reading
There are three ways to receive Pulse Ox data from your Garmin watch, as detailed below.
When 'Manual Check' is enabled, this means the feature won't be draining battery life in the background.
Instead, it will lay dormant until you decide to perform a manual spot-check from the watch's Pulse Ox widget.
That figure will then show (along with how long ago it was taken) until you take another manual reading.
An average figure will also show if you decide to take multiple readings within the space of five minutes.
Monitoring your blood oxygen during sleep only is a bit of a middle ground, allowing you to still receive Pulse Ox from your night but not have the feature drain battery during the day.
As we mentioned above, it's also especially useful for those wanting an indication of whether they may suffer from sleep apnea.
With this mode turned on - which can be performed by heading to the Pulse Ox widget and finding the 'Pulse Ox Mode' within settings - your Garmin watch will measure SpO2 levels every minute during sleep.
This will begin and end based on the sleep/wake times set within Garmin Connect.
For those who want around-the-clock insights into their SpO2 levels, turning on 'All Day' via your Garmin watch is the best option.
Like with the other modes, you'll be able to do this from 'Pulse Ox Modes' within the settings of the Pulse Ox widget on your device.
Interestingly, when this mode is turned on, your watch will take readings less often when it detects a lot of movement (such as when you're exercising).
Just be cautious about the battery drain when this mode is enabled.
Is Garmin Pulse Ox accurate?
With Pulse Ox now available on most Garmin watches, more and more people are understandably wondering whether the blood oxygen saturation data is accurate.
Given the fact that readings are taken from the wrist - and the fact that the feature is only designed to provide an estimation - there are plenty of limitations to it.
The wearer's physical characteristics, the fit of the watch and even the presence of ambient light can impact readings, meaning that there's plenty of room for Pulse Ox readings to be inaccurate.
In our experience, however, Garmin's watches are some of the more consistent blood oxygen estimators, with some devices fluctuating wildly from day to day.
As far as blood oxygen estimations go from the wrist, we think Pulse Ox is pretty accurate.
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