An Accuracy study of the Swiss Federal Institute of Sports in Magglingen showed that the Accuracy of a Holter ECG is lower during exercice than a Polar H10 chest strap: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiKos3IhuH4AhWF_bsIHfGlD2kQFnoECAIQAQ&url=https%3A%2F%2Fwww.ppdb.ehsm.ch%2Finf2%2Frm%2Ff.php%3Ff%3D20200416162130_5e9869eab833b.pdf%26n%3DGilgenAmmann_RRIntervalSignalQuality_2019.pdf&usg=AOvVaw23MOAobT8so8HFGAdgdcPo A schematic of electrodes and HR chest strap placements on participant is shown in the paper. It shows, that the Holter ECG has long …