Validation of Hexoskin Biometric Shirt to Cosmed k4b2 Metabolic Unit in Adults During Trail Running

Abstract

The development of new wearable biometric technologies have increased in recent years. The Hexoskin biometric shirt is a wearable technology designed to monitor biometric measures including heart rate (HR), ventilatory rate (VR), minute ventilation (VE), steps, and energy expenditure (EE). It is unknown whether the Hexoskin produces valid results for these measures in real-world applications. PURPOSE: To validate biometric measures using the Hexoskin against the Cosmed k4b2 portable metabolic unit during trail running. METHODS: Participants (N=26) completed a self-paced one-mile trail run wearing the Hexoskin and the Cosmed unit. Biometric measures (HR, VR, VE, steps, and EE) were recorded each minute by the Hexoskin and breath-by-breath by the Cosmed. Data for HR, VR, and VE were analyzed in 6 one-minute intervals, the first three minutes (min: 1, 2, 3) and the last three minutes (min: 1’, 2’, 3’). Data for steps and EE were analyzed for the entire one-mile trail run. RESULTS: All Hexoskin and Cosmed data were analyzed using intraclass correlation with significance at p<0.05 level. Only one HR measure, the second to last minute, showed significant correlation (HR 2’: ICC=0.342, p=0.041). All other HR measures were not significantly correlated (HR 1: ICC=0.029, p=0.443; HR 2: ICC=0.115, p=0.283; HR 3: ICC=-0.11, p=0.552; HR 1’: ICC=0.253, p=0.102; HR 3’: ICC=0.045, p=0.412). All VR measures at all time points were significantly correlated (VR 1: ICC=0.744, p<0.001; VR 2: ICC=0.626, p<0.001; VR 3: ICC=0.936, p<0.001; VR 1’: ICC=0.926, p<0.001; VR 2’: ICC=0.897, p<0.001; VR 3’: ICC=0.796, p<0.001). The remaining variables (VE, steps, and EE) were not significantly correlated at any time point (VE 1: ICC=-0.195, p=0.835; VE 2: ICC=-0.020, p=0.540; VE 3: ICC=-0.039, p=0.577; VE 1’: ICC=0.144, p=0.237; VE 2’: ICC=0.118, p=0.279; VE 3’: ICC=0.091, p=0.325; steps: ICC=0.154, p=0.222; EE: ICC=-0.058, p=0.614). CONCLUSION: Our results indicate the Hexoskin provides valid real time measures of VR and HR in the second to last minute of activity. Hexoskin validation results for all other measures (HR, VE, steps and EE) may improve with improved Hexoskin biometric shirt HR detection methods.