In the LabChart HRV Module, the normalized units for LF are calculated with the following Equation:
100.0 * LF Power / (Total Power - VLF Power)
This means that we multiple the low frequency power (us^2) by 100.0. We then divide by the result of total power (us^2) minus the very low frequency power (us^2)
The normalized units for HF are calculated with the following Equation:
100.0 * HF Power / (Total Power - VLF Power)
If you have further questions or concerns about this, please contact your local Technical Support Representative by completing the online form located HERE.