Investigation of Possible Effects of Wearing Exoskeletons during Welding on Heart Rate

Abstract

This study aims to investigate the possible effects of wearing exoskeletons during welding on heart rate. Additionally, the validity of a measuring instrument for determining acute heart rate is to be assessed. N = 15 young healthy subjects with welding experience took part in the study. The study design defines a one-hour workflow that abstracts welding and grinding tasks. The sequence is based on the internationally recognized standard DIN EN ISO 9606-1 and reproduces authentic work sequences in constrained body positions. Each subject completed the workflow once with and once without an exoskeleton. Recorded measures were the heart rates measured by a wrist-worn smartwatch and by Impedance Cardiography (ICG). The average heart rate shows no statistically significant differences in the measurement series with and without exoskeletons. The temporal variation of the heart rate shows a statistically significant influence of wearing exoskeletons and provides a moderate to strong effect, corresponding to a Cohens d of d = 0.78. Only 28.57% of all data series obtained with a smartwatch were equivalent to ICG-data after analysis with t-test, Pearson’s correlation, and orthogonal regression. Using averaged heart rates to assess exoskeleton effects is not a suitable measure. A trend analysis using linear regression shows moderate to strong statistically significant effects in the time course of heart rates and provides an approach to evaluate exoskeleton-induced effects.