The raw respiration signal has arbitrary units, the mL values are calculated on the TidalVolume and MinuteVentilation only (please refer to this link).
We do a general calibration using the weight and height of the user, but it is not a complete calibration per se. Looking in the user’s profile, you can see the calibrated_coef value.
A coefficient applies a multiplication factor to convert Raw data into adjusted value in Liter. You can change that coefficient to fit any calibration using an API call. We plan to revisit this calibration method. Calibration may require an external device for a real gold standard reference, such as a spirometer.
Keywords: respiratory metrics, conversion factor