Glossary · Health
SpO2 (blood oxygen)
SpO2 is the oxygen saturation of the blood. Smartwatches and smart rings estimate it with light sensors on the skin.
What does SpO2 (blood oxygen) mean?
The sensors shine red and infrared light into the skin and measure how much of it comes back. From this, the device calculates how much oxygen the blood carries.
What is mainly interesting is the trend during the night. Noticeable drops can point to breathing pauses during sleep. The values depend heavily on how tightly the watch fits and are no substitute for a medical measuring device.
A general explanation of the term, not from a video. How it plays out on a specific device in everyday use is covered in the reviews below.
