2019 was the year the Polar OH 1 has been released & the most interesting papers about smartwatches where published we know. DC reviewed the Polar OH1 on March 20, 2019: https://www.dcrainmaker.com/2019/03/polar-oh1-plus-optical-hr-sensor-in-depth-review.html A PLOS ONE paper about the Polar OH has been published in May 23, 2019: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217288 And the other papers which where interesting … Continue reading 1500. The last scientific paper about smartwatches which is worth mentioning for us personally was published in 2019