This article explains the Hexoskin data channels used to measure respiration and ventilation, and their associated units of measurement.
Raw Data
The raw respiration data includes the following data channels:
- inspiration (a.u.)
- expiration (a.u.)
- respiration_thoracic (a.u.)
- respiration_abdominal (a.u.)
Each of these data channels reports values in arbitrary units (a.u.) related to the variation in the electronic signal in the respiratory bands.
Note: During inspiration, the respiratory bands expand and the arbitrary unit values decrease. During expiration, the respiratory bands get narrower and the arbitrary unit values increase.
Processed Data
The processed respiration data includes the following data channels:
- breathing_rate (rpm)
- tidal_volume (mL)
- tidal_volume_adjusted (mL)
- minute_ventilation (mL/min)
- minute_ventilation_adjusted (mL/min)
The breathing rate is calculated over the last 7 respiration cycles and is reported in respirations per minute (rpm).
The tidal volume shows the volume of air inspired in the last individual inspiration and is reported in milliliters (mL).
The minute ventilation shows the volume of air per minute inspired during the last 7 complete respiration cycles, reported in milliliters per minute (mL/min).
Note: Tidal volume and minute ventilation are obtained using a predefined conversion factor of 13.28 that is applied to the total respiration raw signal. This conversion factor is used to translate the arbitrary units (a.u.) of the raw respiratory signal into meaningful volumetric measurements.
The adjusted tidal volume and adjusted minute ventilation are calculated and reported in the same way as their standard versions, but the conversion factor is modified to take into account the user's weight and height.
Please refer to our API documentation here for more details.
Calibration
To further increase the precision of the ventilation data, you can perform a user-specific calibration using a reference device such as a spirometer. This calibration helps to personalize the conversion factor used to translate the raw respiratory signal into meaningful volumetric measurements of tidal volume and minute ventilation.
Here's a support article explaining how to conduct this calibration.
Important: For the calibration to be relevant, it must be repeated each time an individual puts on the Hexoskin shirt again.
If you have any questions regarding the Hexoskin respiration data, please contact support@hexoskin.com.
Keywords: respiratory metrics, conversion factor