SpO2 data messages store the blood oxygen saturation readings of the pulse oximeter, during spot checks, at night or all day.
Moment the message refers to, in UTC. FIT stores it as seconds since the FIT epoch (December 31, 1989, 00:00:00 UTC); decoders usually expose it as a regular date.
Blood oxygen saturation (SpO2) reading.
readingConfidenceUint8Confidence of the reading.
modeEnumHow the reading was taken: spot check, continuous, periodic or off wrist.
offWristspotCheckcontinuousCheckperiodicmesgNumStringGlobal message number identifying the kind of message. Decoders use it to know which profile to apply to the data.