How Do I Convert Respiration Data (Arbitrary Units) Into Volume (mL)?
Hexoskin’s raw respiratory data is measured in arbitrary units based on ribcage movement. To convert this data into volume (mL), a formula and calibration procedure using a spirometer are required.
Hexoskin measures ribcage movement during breathing, and the respiration data is expressed in arbitrary units. To convert it to volume in mL, use this formula:
Volume (mL) = ΔRespiration × 13.28 × (Weight / 65)
To obtain absolute values, a calibration step is required using a spirometer. This involves recording a forced expiration with both the spirometer and Hexoskin at the same time. The volume measured by the spirometer is matched to the Hexoskin signal amplitude to calculate a personal conversion factor.
While Hexoskin provides precise data, accuracy varies between users. Calibration should be done for each user, every time the shirt is worn.