The Institute for Intelligent Systems Research and Innovation, Deakin University, Waurn Ponds, VIC 3216, Australia used a gtec medical device with 64 channels which costs more than 50 000 USD to validate the accuracy of the Polar OH1: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217288 and published a paper in PLOS ONE about it. No follow up papers followed in higher …