Overnight spO2 is Interesting but why is it not displayed in the app? So you can see changes over time... : r/fitbit
101 Guide for Fitbit Charge 2
How to enable the SpO2 monitor on your Fitbit | iMore
Amazon.com: Fitbit Sense 2 Advanced Health and Fitness Smartwatch with Tools to Manage Stress and Sleep, ECG App, SpO2, 24/7 Heart Rate and GPS, Blue Mist/Pale Gold, One Size (S & L
Fitbit Charge 4 update shows SpO2 data on the band itself, tracks skin temperature - GSMArena.com news