Automated HRV Data Processing Protocol

HRV RR data, the length of time between normal successive heart beats, is transferred via Bluetooth® technology to the ActiLife software. It is then downloaded as a text file. The text file is saved as a CSV file and uploaded to Kubios HRV analysis software. Data is manually cleaned in the CSV file before uploading to Kubios. Participant information including age, height, weight, and sex is input in Kubios for accurate analysis. The final 5 minutes of the recording are used for analysis. Kubios uses a threshold-based artifact correction algorithm that compares every RR interval against a local average interval.³⁶ The correction level is adjusted for each participant because there are inter-individual differences in HRV, so using a fixed threshold does not work optimally for all participants.³⁶ The correction level chosen for each participant is the lowest level that correctly identifies artifact without over-correcting normal beats as artifact. Recordings with greater than 2% artifact are excluded from analysis because even a small number of edited RR intervals (<5%) can have a great influence on HRV results.^{37 (link)} Kubios utilizes Fast Fourier Transform to run frequency domain analyses.^{29 (link)} Research assistants spend an average of 15 to 20 minutes to score HRV data from each participant for the ongoing study.