Smartwatches to not fullfill the requirements of gold standard for heart rate measurements, which are: If these requirements are not full-filled, it has to tested if the smartwatches deliver reproducable and accurate data. So how to proceed? An refer to a paper of the Swiss Federal Institute of Sport Magglingen SFISM: https://pubmed.ncbi.nlm.nih.gov/31004219/#full-view-affiliation-1 2. Then Peter …