I have stresslocator but it is uncomfortable and clunky and does not have accelerometer for movement detection so end up wearing my smart watch as well. Fitbit and others hate announced new software for their devices allowing for o2 sat detection. Please integrate!
AFAIK Fitbit and Garmin are the only ones featuring SpO2 meters on smartwatches. But sadly neither of those have a public access to the sensor data for 3rd party developers.