Blood oxygen saturation (SpO2) estimates the amount of oxygen in your blood as a percentage of the maximum it could contain.
This is measured per minute.

The "Minute SpO2" files contain the SpO2 measured per minute during sleep.

Values per row:
- timestamp: the time when SpO2 was measured
- value: SpO2 value
- confidence: An estimation of how much confidence we have in the SpO2 measurement
- coverage: The number of seconds in the last minute that were used in the calculation
- valid: False if low confidence
- unused: whether is used or not in the summary computation