Rahel Gilgen-Ammann, Theresa Schweizer and Thomas Wyss from the Swiss Federal Institute of Sport Magglingen published a paper about the RR interval signal quality of a heart rate monitor and an ECG Holter at rest and during exercise in the European Journal of Applied Physioly. 2019 Jul;119(7):1525-1532. https://pubmed.ncbi.nlm.nih.gov/31004219/ They compared the accuracy o fa Schiller …