Segmented-Beat Modulation Method-Based Procedure for Extraction of Electrocardiogram-Derived Respiration from Data Acquired by Wearable Sensors During High-Altitude Activity

High-altitude sports are affected by hypoxic stress-related alterations and, consequently, may trigger severe events such as sport-related sudden death; thus, into-the-jield monitoring of respiration is essential. A Segmented-Beat Modulation Method (SBMM)-based procedure was previously proposed to extract electrocardiogram (ECG) - derived respiration (EDR) . The aim of this study is to validate SBMM-based procedure for EDR extraction in data acquired by wearable sensors during high-altitude physical activities. Respiration signal (RES) and ECG were recorded using BioHarness 3.0 by Zephyr from 3 expeditioners, while performing a trek up to 4, 556m of altitude. EDR{\it was} extracted from ECG by SBMM-based procedure. RES and EDR were segmented into 60-second windows and characterized in terms of breathing rate ( BR_{RES} and BR_{EDR} , respectively). BR_{RES} and BR_{EDR} were compared by absolute difference (\vert \delta\vert) , concordance correlation coefficient (CCC) and linear regression analysis. Results confirmed EDR goodness, proved by low values of \vert \delta\vert (2[1;4]cpm) , satisfactory CCC(0.62 ; P-value < 0.05 ) and good fit of regression line (BR_{RES}=0.91\cdot BR_{EDR}+4.47cpm) . In conclusion, SBMM-based procedure is a good method to extract EDR from data acquired by wearable sensors during high-altitude physical activities.