In an independent validation study published in "Applied Physiology, Nutrition, and Metabolism", University of Waterloo researchers showed that Hexoskin smart shirts closely tracked the laboratory standard methods for cardiac, breathing and activity measurements.
Here's the abstract from the study:
We tested the validity of the Hexoskin wearable vest to monitor heart rate (HR), breathing rate (BR), tidal volume (VT), minute ventilation (VE) and hip motion intensity (HMI) by comparison with laboratory standard devices during lying, sitting, standing and walking. Twenty healthy young volunteers participated in this study. First, participants walked 6 minutes on a treadmill at speeds of 1, 3 and 4.5 km/h followed by increasing treadmill grades until 80% of their predicted maximal heart rate. Second, lying, sitting and standing tasks were performed (5 minutes each) followed by 6 minutes of treadmill walking at 80% of their ventilatory threshold. Analysis of each individual’s mean values under each resting or exercise condition by the two measurement systems revealed low coefficient of variation and high intra-class correlation values for HR, BR and HMI. The Bland-Altman results from HR, BR and HMI indicated no deviation of the mean value from 0 and relatively small variability about the mean. VT and VE were provided in arbitrary units by the Hexoskin device; however, relative magnitude of change from Hexoskin closely tracked the laboratory standard method. Hexoskin presented low variability, good agreement, and consistency. The Hexoskin wearable vest was a valid and consistent tool to monitor activities typical of daily living such as different body positions (lying, sitting, and standing) and various speeds of walking.
Click here to access the complete paper: http://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2015-0140